100 CFU/ml Water

Literally signifies one hundred colony forming units (CFU) per milliliter of water. Bacteria usually require a minimum number of individual organisms to be located in a given region in order to produce a colony. The minimum number of bacteria is called a colony forming unit. The bacterial burden or infective potential of a sample of water is often listed as the number of CFU in each ml. One common cutoff is 100 CFU per ml of water.

AIDS

Acquired Immunodeficiency Syndrome. The main illness caused by the human immunodeficiency virus (HIV). AIDS is acquired when the HIV retrovirus-infected blood or fluids is transmitted to the mucous membranes or bloodstream of an unaffected individual. HIV destroys a specific cell in the immune system known as CD4 positive T type white blood cells and the immune system starts to fail. Once the number of these CD4 cells drops below a certain value OR a patient develops an AIDS-related disease, the infected person is considered to have AIDS, rather than simply HIV infection. Pneumocystis pneumonia and Kaposi’s Sarcoma are two examples of opportunistic infections that occur almost exclusively in patients with AIDS.

Activity

Activity refers to the type of microorganism(s) that a disinfectant can kill, inhibit, or inactivate. Possible terms that describe the activity of a disinfectant are bactericidal, yeasticidal, fungicidal, mycobactericidal, tuberculocidal, limited virucidal (virucidal against enveloped viruses), virucidal and sporicidal.

Adenovirus

Double-stranded DNA viruses that lack an envelope, are medium in size (roughly 100 nm), and are icosohedral in shape. So far over 50 different adenoviruses have been identified that cause human disease. These viruses are well known causes of respiratory illnesses but can affect the gut, eye, ear, throat, and skin. Less common sites of infection are the urinary bladder and the meninges of the brain. There is no curative treatment for adenovirus infection. Reducing the spread of adenoviruses involves contact and droplet precautions and meticulous infection control practices.

Aerosol

Ultrafine particles or droplets of liquid that are dispersed and carried in the air. May refer to industrial or medical products that are contained under pressure and intended to be inhaled, used topically, or meant to cover a wide area or volume. Theoretically, any substance of an appropriately small size and carried in the proper aerodynamic disturbance could become an aerosol. An aerosol may also carry infectious material as can occur in dental procedures involving rotary instruments or expelled by sneezes and coughs. An aerosolized pathogen can carry on the air and contaminate surfaces or infect individuals.

Air removal test

A diagnostic test for prevacuum steam sterilizers that verifies the ability of the device to create a vacuum in the chamber. A common air removal test is the Bowie-Dick card air removal test. This credit card shaped device completely changes color in the presence of a vacuum or partially changes color if there is a seal leakage, inadequate steam penetration, or vacuum pump failure. Another air removal test device is the DART-type device that operates by the same principle.

Airborne Infection

The spread of aerosolized pathogens from a carrier animal/person to a susceptible host. The pathogens are carried through the air on small droplets (100 µm to 2 mm diameter) introduced by forcible exhalation (e.g., speaking, coughing). Generally, these droplets must be inhaled or inoculated to cause infection in the host.

Airborne transmission

One of the main modes of travel for microorganisms. Airborne transmission requires that the infectious particle be carried through the air and remain in the air for extended periods of time. This is usually accomplished when the infectious particle is less than 6 micrometers in diameter or the microorganism is carried on dust particles. Airborne transmission is distinguished from droplet transmission in that droplets are large enough to be affected primarily by gravity while airborne particles generally are not.

Alcohol-based hand rub / disinfectant

A liquid, gel, or foam containing ethanol, isopropanol, and/or n-propanol intended to disinfect the skin on the hands by direct contact. The alcohols have germicidal activity against Gram-positive and Gram-negative bacteria, mycobacteria, fungi as well as most viruses (best against enveloped viruses).

Alcohol-based hand sanitizer

Liquid gel or foam containing ethanol, isopropanol and/or n-propanol, designed to disinfect the skin of the hands through direct contact. Alcohols exert a germicidal activity against Gram-positive and Gram-negative bacteria, mycobacteria, fungi and most viruses (especially against enveloped viruses).

Alcohols

Class of organic molecules in which a hydroxyl group (–OH) is covalently bound to carbon. The hydroxyl group participates in hydrogen bonding to a certain degree making alcohols with small carbon chains (e.g. ethanol, isopropanol, and n-propanol) soluble in water. Alcohols can be chemically converted into various organic molecules (e.g. dehydrated to form alkenes). The ability of alcohols to denature proteins makes them useful as antimicrobial agents. Their speed of action is fast and in concentrations between 60 and 95%, alcohols efficiently inactivate Gram-positive and Gram-negative bacteria, mycobacteria, fungi as well as most viruses (best against enveloped viruses).

Aldehydes

Organic compounds containing a functional, terminal carbonyl group covalently bound to hydrogen and R (shown). An aldehyde can be reduced to form an alcohol (R-COH) or oxidized to form a carboxylic acid (R-COOH). Common examples include formaldehyde, acetaldehyde, and glutaraldehyde. Aldehydes are particularly reactive to nucleophilic species at the carbonyl carbon.

Alkali

Pure alkali metals (Group 1 of the periodic table) are extremely reactive and not often found in nature in their elemental state. In biology, alkalis are compounds in which a hydroxide ion is ionically bound to an Alkali metal (e.g. lithium, sodium, potassium to form LiOH, NaOH, KOH). Alkalis are strongly basic substances that form hydroxide ions when dissolved in water. Alkalis act as strong detergents as they can saponify fats, grease, and oils and remove blood and proteins from objects.

Alkylamines

Alkylamines are surface-active (i.e., detergent) compounds that are both polar and nonpolar (also known as aliphatic amines). This property allows the molecule to act as a surfactant/detergent. Alkylamines are versatile and useful as wetting agents, emulsifiers and detergents. Alkylamines are frequently used in surface and instrument disinfectants.

Allergen

Any small particulate matter that is capable of stimulating a Type 1 hypersensitivity reaction (allergic reaction, immediate hypersensitivity). Allergens are nonparasitic antigens capable of inducing this immune system response. Common allergens include dust mite waste, pollen, and pet dander however any particle that is smaller than 80 microns can act as an allergen in a susceptible person.

Allergic contact dermatitis

A delayed (Type IV; cell-mediated) allergic response to a specific antigen on or within the skin. This dermatitis requires that the person was previously exposed and sensitized to the antigen. The antigen binds to Langerhans cells in the skin which initiates a T cell-mediated immune response. Worldwide the most common cause of allergic contact dermatitis is nickel; in the United States the most common cause is urushiol oil (poison ivy and poison oak). Allergic contact dermatitis is different, yet often confused with contact dermatitis, which causes skin damage without immune system involvement.

Amines

Organic compounds that contain a nitrogen atom that is singly bound to three other substituents or part of an aromatic ring. In order to be an amine, the nitrogen atom must be bound to either a carbon or hydrogen atom. Amines are an integral part of the amino acid backbone and thus peptides and proteins. They are present in various endogenous and exogenous biologically active molecules.

Anionic surfactants

A surfactant is a substance that decreases the surface tension of a liquid. It functions in a similar fashion to a detergent in that surfactants have a hydrophilic (“water loving”) head and a hydrophobic (“water hating”) tail which form micelles. Anionic surfactants contain an anion (negatively charged ion or atom) as the hydrophilic head. A common anionic surfactant is fatty acid soap.

Antibacterial

An agent (e.g. soap or disinfectant) that has activity against bacteria. This activity may be bacteriostatic (i.e., inhibits bacterial growth) or bactericidal (i.e., kills bacteria).

Antibiotic resistance

A term applied to bacteria that have developed the ability to survive the bactericidal or bacteriostatic effects of certain drugs through genetic mutation or inducible genes. This genetic change in the bacteria renders the antibiotic less effective or useless. The mutation or inducible changes are then passed to the progeny of the bacteria; thus entire colonies of bacteria can become resistant to certain antibiotics. When these antibiotic resistant microorganisms cause human disease, treatment options are severely limited.

Antibiotics

A medication that destroys bacteria or prevents them from reproducing. In general, antibiotics are molecules that are derived from substances produced by fungi or bacteria to eliminate competition for food or environmental resources. Modern antibiotics are either produced from these molecules or chemically related synthetic analogs. Certain antibiotics have bactericidal or bacteriostatic action against one or a few types of bacteria. When a drug can affect various types of bacteria it is referred to as a broad spectrum antibiotic.

Antibodies

Large proteins known as immunoglobulins that act as a molecular recognition device for the immune system. An antibody is a Y shaped protein that has a specialized antigen-recognition site on two ends while the third end interacts with other parts of the immune system to announce when it has detected an antigen. The antibody only detects a small portion of the antigen, a region the size of a few amino acids called the epitope. The epitope determines the specificity of the antibody for a particular antigen. Antibodies have been engineered and adapted for a variety of medical and industrial applications because of their ability to differentiate between various antigens (peptides).

Antigen

A substance that binds to a precise location on an antibody and causes a particular conformational change in the structure of that antibody. When the antibody is functioning within the immune system, the conformation change caused by the antigen prompts an immune reaction. Antigen-antibody binding has been used for chemical detection. In these cases the conformational change in the antibody signals the presence of the antigen to the observer. A common example is the home pregnancy test in which beta-human chorionic gonadotropin (ß-hCG) is the antigen and binds to the antibody-impregnated detector stick. When ß-hCG is present, it induces a color change.

Antimicrobial

An agent that has activity against microorganisms. Antimicrobial often refers to an agent that has activity against more than one type of microorganism (e.g., activity against bacteria, fungi, viruses, etc.).

Antisepsis

Inhibiting the growth of microorganisms to prevent colonization or infection. This term refers to steps taken to reduce the number of microorganisms in a local environment.

Antiseptic

Any material that can produce antisepsis and has antimicrobial activity. An antiseptic can either kill or inhibit the growth of microorganisms thus preventing or reducing the risk of infection from pathogens.

Asepsis

A condition or environment that is completely devoid of pathogenic microorganisms including bacteria, viruses, fungi, and parasites. The term asepsis is often used interchangeably with “sterile.” Surgical asepsis includes the techniques and precautions required to ensure an environment that is free of pathogenic microorganisms for the purpose of performing surgery. Asepsis can for instance be achieved with chemical sterilizing agents, dry-heat or pressured-steam sterilization (such as in an autoclave) and is maintained through proper ventilation and barrier protection.

Aspergillosis

The presence of Aspergillus molds on the surface or within tissue that leads to symptoms. Aspergillus primarily affects the skin or the lungs. Pulmonary aspergillosis can cause breathing problems, chronic pneumonia, and even aspergilloma or a fungal ball. Dermatological aspergillosis is relatively rare but causes various cutaneous lesions and rapidly leads to “burnt,” necrotic areas of skin known as eschars. Aspergillus is an opportunistic pathogen and generally requires a deficiency in the skin or disease in the lungs in order to cause aspergillosis.

Aspergillus niger

A species of the fungus Aspergillus that is not necessarily pathogenic but can cause human disease. Aspergillus niger is a cause of invasive pulmonary aspergillosis (fungal infection of the lungs) and may lead to the formation of aspergilloma (fungal “ball” found in the lung). It can colonize the external ear canal and is the major cause of otomycosis (superficial fungal ear infection). Since Aspergillus niger is ubiquitous, the air always contains Aspergillus niger spores. In the environment, it is a leading laboratory contaminant. This species of Aspergillus is named for its black or dark brown conidial head.

Asymptomatic

A state in which a person is without symptoms of a particular disease or infection. This is not necessarily synonymous with a disease-free state since infected persons can be symptom-free in the prodromal phase of an infection. Likewise, certain viral infections may persist without producing symptoms. For example, varicella zoster virus is infectious prior to causing symptoms (thus the person is asymptomatic). After active chickenpox with lesions and fever, the virus retreats to the dorsal root ganglia. At this point the person is again asymptomatic until herpes zoster or shingles happens to occur later in life.

Autoclave

A device that applies sustained heat (dry or pressured steam) to instruments and reusable supplies in order to kill any microorganisms that may be contained in or on them. The standard autoclave creates a temperature of 134° C for three minutes or 121° C for 15 minutes. This temperature is effective at killing bacteria, viruses, fungi, and spores (though prions may survive this process). Cold sterilizers, gas autoclaves, and ultraviolet autoclaves achieve sterility through different mechanisms.

Autoclaving

The process of using a pressurized, moist, heated enclosure (i.e., autoclave) to sterilize instruments, materials and certain equipment. One major advantage of autoclaving is that it can destroy heat-resistant bacterial spores.

Autoimmune disease

An autoimmune disease is an illness in which the immune system detects an endogenous or native protein as foreign and mounts an immune response against it. This immune response usually results in the destruction of the cells/tissues that contain this epitope. Examples of autoimmune diseases include type I diabetes, lupus erythematosus, and myasthenia gravis. Since it is impossible to completely remove the antigens from the body, which are present on normal tissue, treatment is aimed at inhibited the aberrant immune system response.

Avian flu / Bird flu

Human infection with a zoonotic influenza A virus that primarily affects birds. While all influenza A viruses can infect birds, the viruses capable of causing avian flu also have the ability to cause symptoms in humans. There are various serotypes of avian influenza including H3N2 and H5N1 (considered the greatest threat to humans). Avian influenza is transmitted from animals to humans and is thus a zoonotic virus. It may infect humans that contact sick, dying, or dead infected poultry.

Bacillus sp.

A genus of aerobic or facultatively anaerobic Gram-positive bacteria occurring in the shape of rods and capable of forming spores. Bacillus species are primarily found free-living in soil and few are pathogenic to humans. The two major pathogenic species are Bacillus anthracis (causes Anthrax) and Bacillus cereus (causes food-borne illness). Bacillus bacteria are identified in part by their ability to secrete certain enzymes, including catalase; a phenotype that is helpful for laboratory diagnosis.

Bacteria

Single-celled organisms that lack an organized cell nucleus or chlorophyll. They reproduce by binary fission (mitosis). Bacteria may be aerobic, anaerobic; commensal, parasitic or pathogenic. Bacteria can by differentiated in a laboratory setting be their morphological, structural, and physiological traits.

Bacterial count

The concentration of bacteria within a given sample, usually in a fluid. Bacteria can be counted in several ways with differing degrees of precision. The amount of bacteria or colony forming units (CFU) per a unit volume (such as a milliliter) is measured and reported. Assuming a homogeneous mixture in the tested fluid, the bacterial count of the sample provides an estimate of bacterial concentration of the fluid.

Bacterial count

Concentration of bacteria within a given sample, usually a fluid. Bacteria can be counted in several ways and with varying degrees of accuracy. The amount of bacteria or colony forming units (CFU) per unit of volume (such as a milliliter) is measured. Assuming a homogeneous mixture within the fluid being tested, the bacterial count of the sample provides an estimate of the bacterial concentration of the fluid.

Bactericidal activity

The capacity of a disinfectant to kill bacteria. Not identical to bacteriostatic activity. For proving bactericidal efficacy of disinfectants, European standards require in vitro tests (quantitative suspension tests; in the European Norms referred to as phase 2/step 1; e.g. EN 13727). According to the European norm, the four test organisms required for claiming bactericidal activity are Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Enterococcus hirae. The U.S. Environmental Protection Agency (EPA) requires three test organisms for a bactericidal activity claim which are Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella choleraesuis.

Bactericides

The ability to inhibit the proliferation of bacteria. The role of bacteriostatic antibiotics in medicine is to slow the growth and spread of a bacterial infection so that the immune system can effectively respond to it. Bacteriostasis is differentiated from bactericidal agents, which kill bacteria. Some antibiotics have bacteriostatic and bactericidal properties depending on the concentration of the drug and the bacterial infection being treated.

Bioburden

The number of viable microorganisms living in or on a surface prior to sterilization. The bioburden can influence the processes required for cleaning and disinfection and the contact time required. Bioburden is also known as bioload and microbial load.

Biocidal Products Directive

The European regulations dealing with the marketing and use of substances and products with biocidal activity in non-agricultural sectors. It is also known as the Directive (98/8/EC). The European Commission takes care of the periodic updating of these regulations.

Biocidal product directive

European regulations that govern the marketing and use of biocidal active substances and products in non-agricultural fields. Also known simply as Directive (98/8/EC). The European Commission updates these regulations periodically.

Biocidal products

Chemicals that kill living organisms. While the term could be applied to any lethal agent, it is mostly reserved for substances that kill microorganisms, insects, rodents and other pests. There are at least 23 different types of biocidal products grouped into four main groups: disinfectants, preservatives, pest control, and miscellaneous biocidal agents.

Biofilm

A layer of non-living, biopolymers (e.g., polysaccharides) that provides adhesion, protection, and facilitates communication between microorganisms of one type. The biofilm describes the microorganisms and the extracellular coating (slime). Microorganisms that exist within a biofilm are generally harder to eradicate because of the unique properties of the biofilm.

Bioindicators

Organisms that undergo reproducible and detectable phenotypic changes in response to alterations in the local environment. For example, the presence or absence of a particular chemical or nutrient may alter the color of coat proteins. Bioindicators are usually differentiated from biomarkers and biomonitors; biomarkers are nonliving molecular indicators (e.g. antigen recognition systems) and biomonitors are bioindicators that provide a quantifiable phenotypic change.

Blood-borne viruses (BBV)

Viruses that are transmitted between persons through direct contact with and intermixing of blood; however many BBVs do not absolutely require blood contact for transmission. Blood-borne viruses are distinguished from vector-borne viruses which require a vector (e.g. a mosquito) for transmission. Common viruses that are blood-borne are hepatitis B virus, hepatitis C virus, and human immunodeficiency virus (HIV). Blood donated for allogenic transfusion is screened for major, disease-causing blood-borne viruses.

CE conformity marking

CE is an acronym, which stands stands for “Conformité Européenne”. When this mark appears on a product it is a declaration by the manufacturing company that the product meets or exceeds all relevant provisions of the European Directives. This marking allows companies to sell within the European Economic Area without adaptation. The presence of the mark informs European consumers that the product has passed health, safety, environmental test standards. The CE Conformity Marking must not be less than 5 mm in height and maintain the proportions shown.

CEN

Comité Européen de Normalisation or European Committee for Standardisation. Provides technical standards for various products sold and used within Europe, including specifications for disinfectant efficacy testing.

Candida albicans

Single-celled fungus that reproduces by budding. The genus is an important human pathogen, responsible for most fungal nosocomial infections of the skin, genitals, and mouth.

Candidiasis

Infection by species of the genus Candida, typically Candida albicans or Candida glabrata. These opportunistic fungi are capable of colonizing, invading, and/or infecting virtually any surface and tissue in the body as well as persistently occupying the blood. Mild cutaneous candidiasis commonly occurs in skin folds (e.g. intertrigo) and candidiasis of the oral mucosa (i.e. thrush) is relatively common in patients with AIDS. People with deficient immune systems or impaired barrier defenses (e.g. skin lesions, burns) can suffer more serious and even life-threatening manifestations of candidiasis such as candidemia and disseminated candidiasis.

Cationic surfactants

A surfactant is a substance that decreases the surface tension of a liquid. It functions in a similar fashion to a detergent in that surfactants have a hydrophilic (“water loving”) head and a hydrophobic (“water hating”) tail which form micelles. Cationic surfactants contain a cation (positively charged ion or atom) as the hydrophilic head such as an ammonium ion. An example of a cationic surfactant is benzethonium chloride, which has germicidal activity for instance against MRSA and other bacteria.

Centers for Disease Control and Prevention (CDC)

One of the main operating agencies under the United States Department of Health and Human Services. The CDC contains eleven institutes and agencies which perform epidemiological studies, laboratory testing, disease surveillance, and basic research in order to prevent, protect against, and respond to diseases.

Central Sterilisation Unit

Facility within a hospital equipped and staffed to sterilise instruments and objects as needed. Often located near or convenient to the surgical center.

Chemical indicator

A substance that produces a visible change (usually a color change) when it encounters a chemical or physical change. Common chemical indicators are substances that detect hydrogen or hydroxide ions to indicate a pH range. Another example is sterilization tape which changes color when it is exposed to certain temperatures and/or pressures.

Chemical sterilant

A chemical substance that can achieve sterility in an environment. Sterilants can completely eliminate all microbial life forms unlike disinfectants which can kill most, but not necessarily all microorganisms. As such, in order for a chemical to qualify as a sterilant it must meet for more stringent standards than disinfectants, though the two are sometimes (though incorrectly) considered as equivalent entities.

Chemiclave

A device that uses high temperatures and chemical vapors to sterilize instruments such as those used for surgery and in laboratories. The chemical vapors may include mixtures of alcohols, aldehydes (e.g. formaldehyde, gluteraldehyde), and/or other liquid sterilants/disinfectants. Chemiclaves may not be appropriate for sterilizing objects that cannot withstand single or repeated exposure to chemical disinfectants.

Chickenpox

A highly transmissible (contagious) primary infection of the varicella-zoster virus (VZV). The term chickenpox refers to the itchy, vesicles (fluid-filled blisters) on the skin. Transmission of VZV most often occurs from inhalation of virus-laden droplets or may be acquired through direct contact with chickenpox vesicles. Generally chickenpox is a self-limited disease whereas VZV moves to a nerve ganglion and remains dormant. Complications from chickenpox arise from scratching blisters which can lead to bacterial superinfection or more commonly, scarring of the skin.

Chlorhexidine

A chemical antimicrobial agent that has bactericidal and bacteriostatic activity depending on its concentration and the type of bacteria it encounters. It is generally more active against Gram-positive bacteria than Gram-negative. It also exhibits activity against yeast and some enveloped viruses. Chlorhexidine is found in mouthwashes and topical (skin) antiseptics.

Chlorine

A chemical element found among the halogens on the Periodic Table. Chlorine gas is highly toxic to humans and other life-forms but when conjugated with other chemicals it can be effectively used as a disinfectant. Elemental chlorine and certain chlorine-containing compounds (e.g. sodium hypochlorite) act as oxidizers and generate free radicals, which destroy vital structures on and within microorganisms.

Cholera

A disease caused by infection with the Vibrio cholera bacterium. Symptoms of cholera include abdominal cramping, nausea, and watery diarrhea. The diarrhea from cholera rapidly leads to severe dehydration, coma, and death if not treated by antibiotics and oral rehydration/intravenous fluid resuscitation. The Vibrio cholera bacterium and subsequently cholera is contracted through the ingestion of infected food or water.

Cholera

A disease caused by infection with the bacterium Vibrio cholerae. Symptoms of cholera include abdominal cramps, nausea, and profuse diarrhea. Cholera diarrhea rapidly leads to severe dehydration, coma, and death if not treated with antibiotics and oral/intravenous rehydration of body fluids. The bacterium Vibrio cholerae and consequently cholera is contracted through the ingestion of infected food or water.

Chronic infection

An infection that persists over time despite treatment and immune system response. Most infectious agents are detected by the immune system and quickly cleared (acute infection) but some microorganisms remain after the initial infection and symptoms have cleared. Alternatively, a chronic infection may occur when the bacteria or viruses resist elimination in the body. Bacteria that form abscesses can remain within the body and tissue because antibiotics cannot penetrate it. Viruses may resist elimination by the immune system for the life of the person.

Class B autoclaves

As classified by the European standard EN 13060, Class B autoclaves are Big sterilizers and create the strictest sterilization environments (of classes B, N, and S). Class B autoclaves are capable of sterilizing wrapped (single or double) or unwrapped items, including solid, porous and cannulated items that do not exceed a length to diameter ratio of 20:3. Virtually all modern and new sterilizers will either be Class S or Class B sterilizers. For re-processing of medical devices, the use of Class B autoclaves is recommended.

Class N autoclaves

Autoclaves that create the least strict sterilization environment (of classes B, N, and S). As classified by the European standard EN 13060, Class N autoclaves are sufficient as Naked sterilizers and suitable for solid items only that will be used immediately. Older sterilizers tend to meet the Class N criteria and these autoclaves are rarely produced presently.

Class S autoclaves

Autoclaves that create a moderate sterilization environment (of classes B, N, and S). As classified by the European standard EN 13060, Class S autoclaves can sterilize Specific products according to the manufacturer's cycle table. Virtually all modern and new sterilizers will either be Class S or Class B sterilizers. For re-processing of medical devices, however, the use of Class B autoclaves is recommended.

Clean conditions

Level of organic load present during efficacy testing of a disinfectant. Indicates an application in which the surfaces of an object have sufficiently low organic material present. An organic load of 0.3% albumin is often used to simulate clean conditions.

Cleaning

The manual or mechanical removal of visible debris from an object. This process reduces the overall bioburden as well as improves the action of sterilizers or disinfectants. Cleaning removes particle matter along with organic and inorganic material that may trap microorganisms and interfere with sterilization. The substances used in cleaning do not necessarily provide antisepsis.

Cleaning conditions

Level of organic load present during tests of the effectiveness of a disinfectant. Indicates an application in which the surfaces of an object have a sufficiently low level of organic material. An organic filler of 0.3% albumin is used in menu to simulate cleaning conditions.

Clostridium difficile

A Gram-positive, anaerobic, spore-forming bacterium that causes several important gastrointestinal diseases. This microorganism may colonize the wall of the colon and not cause symptoms until such time that the normal bacterial flora of the gut is disrupted, Clostridium difficile bacteria increase in number and release toxins. One precipitating factor is oral antibiotics that pass through the entire gastrointestinal tract and kill normal gut flora. Clostridium difficile colitis is currently one of the most common nosocomial infections in United States and certain developed countries.

Cold sterilisation

Cold sterilization refers to sterilization achieved by UV radiation, germicidal gases, or chemical liquids.

Compuestos de amonio cuaternario (QAC)

Iones de amonio charged positively with four replacements. Cuaternary ammonium compounds (QAC) can be used as antimicrobial and disinfectant agents. Starting from its positive charge, the cuaternary ammonium compounds interact with the negative charges on the surfaces of bacteria, viruses and chokes. Cuaternary ammonium compounds subsequently accumulate in the cell membrane, which results in damage to the membrane, leakage of substances from the cells, and finally the death of the microorganism or the inactivation of the virus, respectively. They are active against various bacterias, hongos and some viruses, these compounds do not kill or inactivate endospores, viruses do not envelope, or Mycobacterium tuberculosis. As disinfectants,

Condition of safety

Level of organic load present during tests of the effectiveness of a disinfectant. Simulate an application in which the surface of an object is very soft (high level of organic load).

Contact time / Exposure time

The time in which a disinfectant must be in contact with microorganisms to effectively reduce the number or eliminate those microorganisms. In general the higher the concentration of disinfectant, the less contact time is required (exceptions to this statement exist). For example, if a reservoir of drinking water is treated with a chlorine-containing substance, the contact time must be sufficiently long enough to account for the fact that the chlorine will be diluted substantially.

Contamination

Expose a previously sterilized object to microorganisms that have not esterilized or contaminated it. An adequately prepared surgical environment is considered estéril until the field is broken in any way, at which point it is considered contaminated.

Coronavirus

Enveloped RNA virus that looks like a halo when viewed under an electron microscope and is the second leading cause of the common cold. Since many types of coronaviruses have been identified, we know that there are only a few that cause human disease. It has been established that SARS, or severe acute respiratory syndrome, is caused by a coronavirus although distinct from those that cause colds.

Corrosion inhibitor

A chemical compound that slows the rate of corrosion on a given object. Contained in a disinfectant for instance, corrosion inhibitors reduce corrosion and rust formation and serve to prolong the life span of the disinfected objects.

Creutzfeld-Jakob disease

The most common prion disease in humans which leads to a loss of neurons, a proliferation of glia, and amyloid deposition in the brain. This degeneration of the central nervous system (CNS) leads to rapidly progressive dementia and various neurological findings. Prionoses such as Creutzfeld-Jakob disease are usually transmitted through consumption of infected tissues, especially brain, but may also be inherited. There is still debate regarding the structure and composition of prions, which hinders scientific study of Creutzfeld-Jakob disease and other prionoses.

Critical medical devices

Medical devices that are introduced directly into normally sterile compartments of the body, that penetrate the skin or mucous membrane and come in contact with blood and tissue (including wounds). The designation indicates the potential for the devices to introduce pathogenic microorganisms into “clean” body tissues or fluids or to transfer disease from the patient to the health care personnel. Surgical instruments are critical medical devices as are coronary artery stents, for example. Reprocessing of critical medical devices requires strict sterilization in order to protect the patient as well as health care personnel.

Critical medical devices

Medical devices introduced directly into normal sterile compartments of the body, which penetrate the skin or mucous membrane and come into contact with blood and tissue (including wounds). The designation indicates the potential these tools have to introduce pathogenic microorganisms into clean tissue or body fluids or to transfer disease from the patient to the healthcare professional. Surgical devices are critical medical devices such as coronary stents. The reprocessing of critical medical devices requires strict sterilization in order to protect both the patient and the healthcare personnel.

Critical medical devices

Medical devices that are introduced directly into normally sterile compartments of the body, that penetrate the skin or mucous membranes and come into contact with blood and teeth (including wounds). The designation indicates the potential of the devices to introduce pathogenic microorganisms into the tissues or clean body fluids or transfer the patient's illness to the health personnel. Quirgic instruments are critical medical devices as are stents for the coronary artery, for example. The reprocessing of critical medical devices requires strict sterilization in order to protect the patient as well as healthcare personnel.

Cross contamination

Inadvertent transfer of microorganisms from one person or object to another person or object previously free of these microorganisms (hand cross-contamination). Another danger of cross-contamination is that the newly contaminated area may unknowingly be thought to be clean or sterile while in fact behaving as a source of infected pathogens. For example, a sterile table is used as a rest for an unopened package of sterile gloves, the outside of which is not sterile. The table is therefore assumed to be sterile but in reality it was cross-contaminated. If the table is now being used for sterile instruments, those items will also be cross-contaminated and potentially infectious to the patient.

Cross contamination

The inadvertent passage of microorganisms from one person or object to another person or object that was previously free of those microorganisms. (cross-contamination by means of hands) Another danger in cross-contamination is that newly contaminated area may be assumed to be clean or sterile but actually acts as a source of infectious pathogens. For example, a sterile table is used to hold an unopened package of sterile gloves, the outside of which is not sterile. The table is then assumed to be sterile but was cross-contaminated. If the table is now used for sterile instruments, those objects will also become cross-contaminated and potentially infectious to the patient.

Crushed contamination

Inadvertent transmission of microorganisms from one person or object to another person or object that was free from the microorganisms before (contamination crossed by hand). Another danger of cross contamination is that the contaminated area may be supposed to be cleaned or esterilized, but actually acted as a source of infectious pathogenic agents. Por ejemplo, una mesa estéril se utiliza para apoyar un paquete sin abrir de guantes estériles, cuyo exterior no estéril. The continuation table, if it is assumed that it is estéril, but has sufried crossed contamination. If the table is currently used for esteriles instruments, these objects will also suffer from cross contamination and will be potentially infectious for the patient.

Current and gravity method

Involves the use of steam and pressure to perform sterilization. Steam is introduced through an upper inlet valve, travels through the sterilization chamber with gravity, and is either pulled or pushed out through a lower outlet valve creating current through the system. The steam vapor can be held within the sterilization chamber and, as it condenses, will form a relatively negative pressure within the vessel.

DDM (Directive on Medical Devices)

Acrónimo para Directive sobre Devices Médicos. European Directive (93/42/EEC) which has the objective of unifying the requirements applicable to healthcare products throughout the EU with the general objective of improving patient safety.

DGHM

Acronym which stands for Deutsche Gesellschaft fur Hygiene und Mikrobiologie which is German for the German Society for Hygiene and Microbiology. Founded in 1906, the DGHM is a not-for-profit scientific society dedicated to the promotion of progress in microbiology, immunology, infectious diseases, and hygiene.

DGHM list

A list of the disinfectants evaluated by the Deutsche Gesellschaft für Hygiene und Mikrobiologie e.V. or the German Society for Hygiene and Microbiology. While some still refer to it as the DGHM list, it is now produced by the Verbund für angewandte Hygiene e.V. (VAH) or the Association for Applied Hygiene.

DL (Dosis lethal)

Dose of a substance or source of energy that can consume an organism. A menu expresada en DL50 is the dose that will contain 50% of the analyzed organisms.

Decontamination

It is widely applied to disinfection and sterilization process. It often refers specifically to the elimination of pathogenic microorganisms.

Denaturation

The process of altering the natural state or function of a chemical; generally applies to proteins and ethanol. Denaturation of proteins destroys their secondary and tertiary structure which renders them unable to perform enzymatic, structural, or receptive functions. Denaturation of proteins can be achieved through heat, strong acids or bases, concentrated salts or certain solvents. The denaturation of ethanol adulterates it and renders it impossible to consume for purposes of inebriation.

Dental dam

A thin square of latex or silicone that is placed over the mouth to create a dry, sterile field for dental surgeries. Used most often in endodontic surgeries. A dental dam covers the entire mouth with the exception of the tooth or teeth being treated.

Dental dam

A thin square of latex or silicone that is placed in the mouth to create a dry, sterile environment for dental surgery. Most often used in endodontic procedures. A dental dam covers the entire mouth cavity except for the tooth or teeth to be treated.

Dental instruments

The surgical and non-surgical tools used by dentists to perform various dental procedures. Dental instruments include examination tools, anesthetic administration tools, and surgical instruments. Since they are used repeatedly, they must be fully sterilized between patients. If dental instruments are classified as non-critical or semi-critical medical devices, they must at least be disinfected.

Dental unit water line

High speed air rotor hand pieces require coolant water either from a reservoir (older models) or from a dental unit water line. The dental unit water line tends to retain and stagnate water when the handpiece is not in use. This can lead to biofilm formation, heterogenic bacterial growth, and the infusion of possibly pathogenic bacteria into the mouths of dental patients in case of back flow. While the documented incidence of human disease from these bacteria is limited, there is general agreement that the dental unit water line should contain potable water at all times with low numbers of microorganisms.

Dermatitis

Any inflammation of the skin whether from infection, endogenous medical condition, allergic reaction, or chemical contact. Dermatitis includes symptoms of warmth, redness, and recruitment of immune cells to the site of the dermatitis. Dermatitis can cause a number of different visible changes in the skin and areas of dermatitis may or may not be pruritic (itchy).

Dermatosis

General term that could apply to virtually any abnormality of the skin. The term is generally reserved for non-inflammatory, non-infectious lesions of the skin. The “-osis” suffix usually denotes a pathological state in which there is an abnormal increase or overabundance. Therefore dermatoses normally indicate eruptive or proliferative skin lesions.

Detergents

Substances used to clean debris and organic substances from an object or surface. Detergents usually contain a hydrophilic head, a hydrophobic tail, and are capable of forming micelles. Immiscible substances are dissolved within the hydrophobic region of the detergent micelle while the outer, hydrophilic surface allows the micelle to dissolve in water.

Diphtheria

Confirmed illness caused by infection with the Corynebacterium diphtheria bacteria which leads to abnormalities of the skin and the respiratory tract. The symptoms of diphtheria are probably caused by the toxins released by the bacteria. Corynebacterium diphteria occurs exclusively by colonizing the skin and mucous membranes. The incidence of diphtheria decreased dramatically with the increase of immunizations with diphtheria toxin, however small, sporadic epidemics were still produced.

Diphtheria

Acute disease caused by infection with the bacterium Corynebacterium diphtheriae leading to abnormalities of the epidermis and respiratory tract. The symptoms of diphtheria are mainly caused by toxins released by the bacterium. Corynebacterium diphtheriae exclusively colonizes the epidermis and mucous membranes.b The incidence of diphtheria has decreased markedly with successful diphtheria toxin immunization, although small, sporadic outbreaks still occur.

Diphtheria

Acute illness caused by infection with the Corynebacterium diphtheria bacterium that leads to skin and airway abnormalities. The symptoms of diphtheria are mostly caused by toxins released from the bacteria. Corynebacterium diphtheria is exclusively found colonizing the skin and mucous membranes. The incidence of diphtheria decreased dramatically with the ascendance of diphtheria toxin immunizations however small, sporadic epidemics still occur.

Dique dental

A delgado square of latex or silicone that is placed under the mouth to create a dry aesthetic field for dental cirugías. It is used most frequently in endodontic treatments. Un dique dental cubre toda la boca with the exception of the diente or los dientes que son tratados.

Direct contact transmission

Disease transmission occurs when the infectious agent is transferred through direct contact with an infected source or person. This type of transmission occurs when microorganisms can survive outside the body but are not carried through the air or in droplets.

Directive on biocide products

European legislation on marketing and use of active biocidal substances and products in agricultural fields. It is also known simply as the Directive on Biocides (98/8/EC). The European Commission updates these rules periodically.

Dirty condition

Level of organic load present during an efficacy test of a disinfectant. Simulates an application where the surface of an object is highly contaminated (high level of organic load).

Dirty conditions

Level of organic load present during efficacy testing of a disinfectant. Simulates an application in which the surfaces of an object is highly soiled (high level of organic load).

Disinfectant

Substance capable of killing or inactivating microorganisms on a surface or object. A disinfectant must reduce the number of germs to 99.999% or 99.99% of the original level, depending on the pathogen group. This means that if there were originally 100,000 germs, only 1 germ could survive disinfection. Disinfectants are sometimes divided into three categories according to their antimicrobial spectrum: low-level, intermediate-level, and high-level. A disinfectant capable of killing all forms of microbial life is precisely defined as a sterilizer.

Disinfectants

A product that is capable of killing or inactivating microorganisms on a surface or object. A disinfectant must reduce the number of germs to 99.999% or 99.99% of the original level, depending on the pathogenic group. Meaning, if there were originally 100,'000 germs or 10'000 germs, respectively, only one germ may survive after disinfection.

Disinfection

Destruction of microorganisms by chemical and physical means. It is generally applied for the removal of pathogenic microorganisms from an environment. For example, a hospital room may be disinfected following the discharge of a patient with MRSA in an effort to reduce the risk of nosocomial spread of the drug-resistant bacteria.

Disinfection plan

The disinfection plan explicitly describes the procedures, substances, and minimum standards for cleaning and disinfection for all relevant objects and environments within an institution. It also includes information about monitoring disinfection procedures/quality.

Disposable item

Items manufactured and sold to be used on a single occasion and discarded. A disposable item may be sterile originally but is usually not constructed of materials that can withstand repeated sterilization procedures.

Droplets

While a droplet is an equally reproducible amount depending on the physical properties of the liquid in the droplet, a droplet is a volume of liquid smaller than a droplet. In medicine, a droplet is a particle that could be produced by a sneeze, a cough, or while talking and which can carry a reasonably large number of pathogens. Some infectious diseases are known to be transmitted by droplet transfer such as diphtheria and influenza.

Droplets

While a drop is a fairly reproducible quantity depending on the physical properties of the liquid in the drop, a droplet is a volume of liquid that is smaller than a drop. In medicine, a droplet is a particle that may be produced from sneezing, coughing, or speaking and can carry a reasonably large number of pathogens. Some infectious illnesses are known to be transmitted through droplet transfer such as diphtheria and influenza.

Dry-heat sterilizer

An autoclave that uses low humidity air and high temperatures to sterilize the objects contained within it. Because it does not use steam penetration or a pressurized vessel a dry-heat sterilizer requires relatively high temperatures and long cycle times (eg 170 °C for one hour) to achieve sterilization. Dry-heat sterilization is among the oldest and least expensive sterilizer technologies. Only few heat-stable materials such as glass, metals or porcelain tolerate such high temperatures and this sterilization method is not recommended for reprocessing of medical devices.

decontamination

Broadly applies to the process of disinfection and sterilisation. Often refers to the elimination of pathogenic microorganisms, specifically.

disinfection

Destruction of microorganisms through chemical and/or physical means. Generally applies to the removal of pathogenic microorganisms from a local environment. For example, a hospital room may be disinfected after a patient with MRSA has been discharged in an effort to reduce the risk of nosocomial spread of the drug-resistant bacteria.

dvg extension

Deutsche Veterinärmedizinische Gesellschaft eV or the German Veterinary Medicine Society. Promotes professional standards, research, and training in veterinary medicine.

ESBL

Extended-spectrum beta-lactamase. Enzymes that destroy the functionally important, beta-lactam ring of a wide array of penicillins and cephalosporins. Several types of bacteria produce EBSLs including Enterobacteriaceae, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella species. Certain disinfectants may be rated according to their efficacy against ESBL-containing bacteria.

Effective spectrum

A property of a chemical disinfectant that indicates the types of microbes that a particular disinfectant will kill or inactivate. The effective spectrum assumes a minimum contact time / exposure time in which the chemical disinfectant is in contact with the object or surface. Some disinfectants cannot kill or inactivate certain microorganisms regardless of their contact times and thus the microorganism exceeds the effective spectrum of the disinfectant. At a minimum, the choice of a disinfectant requires an understanding of the effective spectrum of the disinfectant and the degree of disinfection required for a given application (e.g. critical, semi-critical, or non-critical medical devices).

Emollients

A substance that smoothes and softens the skin. It may also hold and retain moisture in the skin. Emollients may be added to alcohol based hand rubs to reduce the drying and skin irritation that can be caused by repeated use of these sanitizers.

Endocarditis

An infection or inflammation of the endocardium or innermost layer of the heart. Infective endocarditis, which is most important clinically, is usually caused by colonization/infection of the heart valves with bacteria (less commonly fungi). Infective endocarditis may be acute or subacute depending on the pathogenic microorganism. Endocarditis can be difficult to treat because the bacteria often form protective biofilms, which inhibit the penetration and action of antibiotics. This biofilm also increases the accumulation of bacterial wastes that can damage the heart valves, leading to valvular insufficiency.

Endoscope

An instrument that allows direct or videographic visualization of a patient’s internal anatomy. When used surgically, an endoscope can be introduced through a relatively small incision. These instruments are used in multiple procedures and must be thoroughly cleaned and sterilized after use.

Enveloped viruses

Viruses that have a phospholipid/glycoprotein membrane (envelope). Clinically important enveloped viruses cause diseases such as hepatitis B, hepatitis C, influenza, and HIV/AIDS. The envelope provides a means for the virus to enter a cell rather than protection from its environment. Enveloped viruses are generally more vulnerable to disinfectants than non-enveloped viruses.

Enzymes

Large, globular proteins that catalyze the chemical transformation of molecules without being consumed or chemically altered. Enzymes reduce the energy barrier to chemical reactions. While most function optimally under physiological conditions, enzymes can also catalyze reactions outside of the body.

Epitope

The portion of an antigen that is specifically recognized by the antigen recognition site of the antibody. It is the simplest form of antigenic determinant. Epitopes can be composed of sugars, lipids or amino acids.

Erysipelas

A superficial bacterial skin infection that is most commonly caused by pathogenic streptococci. Streptococcal toxins are believed to cause the bright red rash that is typical of erysipelas. Most facial infections are caused by group A streptococci while lower extremity infections are more often caused by non–group A streptococci. While it is a superficial infection, erysipelas spreads rapidly through the lymphatic system.

Escherichia coli

Gram-negative bacterium that may colonize the colon and commensal organisms, but can be pathological in other locations (e.g. urinary bladder). The presence of E. coli in water or on surfaces is considered an indicator of faecal contamination. E. coli is one of the microorganisms used to test disinfectant efficacy.

Ethanol

A short chain alcohol (CH3CH2OH) that is commonly found in hand sanitizers and in some surface disinfectants. It has activity against bacteria (including mycobacteria) fungi, enveloped and non-enveloped viruses in high concentrations (the latter when used for at least 30 seconds). Ethanol is not sporicidal.

European Norms (EN)

European Norms (or Standards) contain the rules and guidelines governing a material, product, process or service in Europe. They are established by an expert panel of stakeholders and adopted by one of the recognized European Standardisation Organisations. The regulations are recognized by their EN number.

European community regulations

Regulations that are constructed by the European Council and European Parliament, and by the Commission alone to be abided by in all member countries of the European Union. Once a regulation is passed it immediately takes effect and has binding legal power throughout the member states. European Community Regulations may apply to various industries and commercial interests in member countries. REACH or Registration, Evaluation, Authorisation and Restriction of Chemical substances is a European Community Regulation passed in 2007 which governs the handling, transport, use, and disposal of chemicals in the European Union.

Exposure time

The time in which a surface or object must be exposed to a disinfectant or sterilant in order to achieve the desired effect. The exposure time will vary depending on the type and concentration of disinfectant or sterilization parameters used, such as pressure and temperature.

Feline calicivirus

A virus commonly causes respiratory illness in cats. While it is highly contagious between cats, it is not transmitted to humans. Feline calicivirus is used to study resistance and longevity of noroviruses since it shares a number of important properties, yet is not pathogenic to humans.

Flavivirus

Enveloped, single-stranded, RNA virus of the family Flaviviridae. Flaviviruses cause a number of important human diseases including yellow fever, dengue fever, West Nile encephalitis and hepatitis C. Most flaviviruses are arboviruses, i. e. viruses transmitted by arthropods, and are vector-transmitted through ticks and mosquitoes. Flaviviruses may also be contracted from contaminated meat, unpasteurized dairy products, and blood transfusion.

Food and Drug Administration (FDA)

The major US regulatory agency overseeing the development, marketing, and safety of pharmaceuticals (human and veterinary), medical devices, cosmetics, vaccines, food, and radioactive products. The FDA must either approve or clear particular items for human or animal use in order for them to be legally sold or dispensed in the United States.

Formaldehyde

Colourless, pungent aldehyde commonly used as a preservative. It can be applied as a liquid or gas, though the gaseous form is a potent irritant. Given its wide spectrum of activity, formaldehyde is used as a surface and instrument disinfectant. Formaldehyde is known to be allergenic and carcinogenic in high concentrations.

Fungi

A large, heterogeneous group of eukaryotic organisms. They range from unicellular yeasts to multicellular, filamentous molds to macroscopic mushrooms. Fungi lack the molecular machinery to perform photosynthesis and obtain nutrition from other organisms (i.e. they are symbionts or parasites). They can reproduce by asexual budding or sexual reproduction. Most species are relatively robust and some produce molecules that act as antibiotics.

Fungicidal activity

The capacity of a disinfectant to kill fungi and their spores. Fungicidal efficacy testing of disinfectants is carried out in two stages. Yeasticidal activity includes efficacy against yeast-like fungi such as Candica albicans, whereas fungicidal activity includes efficacy against all fungi and their spores. For proving fungicidal activity of disinfectants, European standards require in vitro tests (quantitative suspension tests; in the European Norms referred to as phase 2/step 1, e.g. according to EN 13624). According to the European Norm, the two test organisms required for claiming fungicidal activity are the non-spore forming Candida albicans and the spores of Aspergillus brasiliensis (Aspergillus niger).

Fungicides

Chemical or biological substances that are used to kill fungi and their spores. In the same way that bacteria respond to antibiotics, fungi are capable of developing resistant to fungicides, therefore they should be used judiciously. If used as a medication, a fungicide is referred to as an antifungal.

GMP

Acronym for Good Manufacturing Practice. GMP is a set of national (e.g., U.S.) or international (e.g., EU) regulations that set minimum quality standards for pharmaceutical and medical device manufacturing. It covers manufacturing processes, documentation requirements, quality control, and recall procedures.

Glutaraldehyde

Colorless, oily chemical with a distinctive odor that has many applications in medicine, science, and industry. It acts as a cold sterilant, biocide, slimicide, fixative, embalming agent, disinfectant and preservative. The glutaraldehyde molecule has two aldehyde groups located on both terminal ends. While it is an excellent disinfectant, it is potentially toxic to humans and must be handled cautiously. It can cause airway irritation and precipitate asthma in sensitive individuals.

Gram staining

Method of staining bacteria developed by and named for Hans Christian Gram. This staining process is one of the main ways of differentiating bacteria and can predict antibiotic susceptibility in some cases. After treating and rinsing bacteria with Gram staining (multistep process with counterstaining), bacteria that retain blue/dark purple staining in their cell wall are considered Gram positive and those that appear pink are considered Gram negative.

Gram-negative

Denotes the lack of a deep blue color change in bacteria when exposed to Gram stain (crystal violet). Gram-negative bacteria do not possess the necessary quantity of peptidoglycans in their cell walls to retain the Gram stain. Gram staining is a simple laboratory test that differentiates bacteria into one of two broad groups (the other being Gram-positive bacteria) depending on the composition of their cell wall. The Gram staining procedure includes a counterstain, which makes Gram-negative bacteria appear red or pink.

Gram-positive

Denotes the ability of Gram stain to cause a deep blue color change in bacteria that possess the necessary amount of peptidoglycans and low lipid levels in their cell walls. Gram staining is simple laboratory test to differentiate bacteria into one of two broad groups (the other being Gram-negative bacteria) depending on the composition of their cell wall.

Group B medical devices

Critical or semi-critical medical devices that contain internal parts that cannot be visually inspected during routine use or without disassembling the device. These internal parts come into contact with fluids that are potentially administered to the patient and therefore require specific disinfection protocols and supplies. Group B medical devices with relevant reprocessing requirements include objects with small hoses, holes or hollow bodies, complex or sensitive surfaces as well as fragile objects and transmission tools.

Group B medical devices

Semi-critical or critical medical devices that contain internal parts that cannot be visually inspected during routine use or without disassembling the device. These internal parts contact fluids that are potentially introduced to patients and thus require special disinfection protocols and supplies. Group B medical devices with raised reprocessing requirements include objects with narrow hoses, holes or hollow bodies, with complex or sensitive surfaces as well as fragile objects and transmission instruments.

Guanidine and guanidine derivatives

A group of organic compounds containing a particular core structure (shown). Guanidine and related derivatives (including guanidine hydrochloride) are powerful denaturants of proteins. Guanidine effects protein denaturation by causing protein unfolding and a loss of tertiary protein structure. These compounds form bases in solution and are used in the synthesis of items as varied as plastics and explosive.

Guidelines of the DGHM

Number of tests and testing methods used to verify the efficacy of chemical disinfectants against bacteria and fungi. Specifically, these regulations apply to disinfection of hands, skin, surfaces, instruments, and linens. Governed by the Disinfectant Commission of the Association for Applied Hygiene (VAH).

Guidelines of the DVG

Guidelines on proving the efficacy of chemical disinfectants intended for veterinary medicine. They were developed for both the food sector and livestock breeding, and comprise methods for testing chemical disinfectants for their efficacy against bacteria, fungi, viruses, and parasites.

Guidelines of the DVV

Number of tests and testing methods used to verify the efficacy of clinical chemical disinfectants against viruses. Specifically, these regulations apply to disinfection of hands, skin, surfaces, instruments, and linens. Includes comprehensive virucidal activity testing. Governed by the Disinfectant Commission of the Association for Applied Hygiene (VAH).

HAV

The abbreviation for the hepatitis A virus. Virus that is transmitted through contaminated food/water and is an important cause of infectious hepatitis. The hepatitis A virus is relatively resistant to disinfectants and can persist in the environment for long periods.

HBV

The abbreviation for the hepatitis B virus. Virus that is transmitted through contaminated fluid transfer (e.g., droplet) and is an important cause of acute and chronic infectious hepatitis, especially among healthcare workers and hospitalized patients. The hepatitis B virus is not normally viable in or transmitted via food/water.

HBcAg

The abbreviation for the core antigen of the hepatitis B viral particle. This antigen is not detectable in the blood using standard techniques however the antibody developed against the antigen, anti-HBcAg is detectable. The presence of anti-HBc antibodies indicates that there was an infection with the hepatitis B virus at some point.

HBeAg

The abbreviation for the viral envelope antigen of the hepatitis B viral particle. When HBeAg is detected in the blood it indicates that the virus is actively replicating and the risk of transmission is relatively high.

HBsAg

The abbreviation for the surface antigen of the hepatitis B viral particle. The first serological marker to appear after initial hepatitis B virus (HBV) infection. It occurs in acute and chronic HBV infection; HBsAg is not detectable in the blood after the immune system fully clears the acute disease but persists in chronic hepatitis B. It is also the serological marker that is present after successful HBV immunization.

HCV

The abbreviation for the hepatitis C virus. Virus that is transmitted through direct contaminated blood transfer (e.g., blood transfusion) and is an important cause of chronic infectious hepatitis. The hepatitis C virus is not normally viable outside of an organism unless it is contained within blood droplets.

HIV

Abbreviation for Human immunodeficiency virus. Enveloped retrovirus that is internalized by CD4 positive T cells and destroys them. HIV is transmitted by blood and genital secretions. If the virus is protected in a moist, favorable environment, it can persist outside of the body and remain infectious for several days.

HIV post-exposure prophylaxis

Sequence of actions taken to immunize the risk of HIV infection after a possible exposure to the HI virus. This may include cleaning the area of presumed inoculation with virucidal agents with activity against enveloped viruses. Also and more importantly, the exposed person takes a short-term regimen of anti-retroviral drugs.

HSV

Abbreviation for herpex simplex virus. Double-stranded DNA viruses causing painful, contagious lesions to human skin and mucous membranes. The viruses are transmitted through oral, genital, or direct contact from a shedding lesion. The virus can go through periods of dormancy in nerve ganglia.

Halogens

Member of Group 17 on the Periodic Table including fluorine, chlorine, bromine, and iodine. These diatomic elements can provide centers of electronegativity to organic molecules. Halogens are highly reactive species and are generally lethal to living organisms depending on concentration and contact time. Chlorine, bromine, and iodine are commonly used in disinfectants.

Hand decontamination

Outdated term describing the process of cleaning hands using an antimicrobial cleaning agent. This procedure is currently referred to as “Hygienic Handwashing”.

Hand decontamination

Obsolete term that describes the process of cleaning the hands with an antimicrobial cleaning agent. Now referred to as hygienic hand washing. ?

Hand disinfection

Process of cleaning hands and forearms with a disinfectant. The two main procedures of hand cleaning, hygienic disinfection and surgical hand disinfection differ according to the degree of reduction/removal of microorganisms from the skin.

Hand disinfection

The process of cleaning the hands and forearms with a disinfecting. The two main types of hand disinfection procedures, hygienic hand disinfection and surgical hand disinfection, are differentiated by the degree to which they reduce/remove microorganisms from the skin.

Hand hygiene

A broad term that includes hand washing, the use of antiseptic hand wash, antiseptic hand rub or hand antisepsis required for surgery. Hand hygiene may also encompass care of the hands performed in the service of reducing the number of microorganisms on the skin (e.g. trimming fingernails and remove debris trapped beneath fingernails) as well as the use of caring products in order to maintain the natural protective barrier of the skin. It is one of the primary methods to reduce fecal-oral transmission of pathogenic microorganisms.

Hand washing

A term that describes traditional washing of the hands with soap and water. Hand washing is generally only effective at removing debris and reducing, but not eliminating, microorganisms from the skin of the hands. Hand washing does not include washing with agents aimed primarily at antisepsis, such as antimicrobial soaps or alcohol-based hand rubs.

Healthcare-associated infection (HAI, HCAI) / Nosocomial infection

Infections and related diseases acquired while in the hospital environment. This does not pertain to infections acquired prior to entering the hospital in patients asymptomatic at admission. Several factors contribute to the spread of nosocomial infections including higher burden of microorganisms in the hospital setting, higher concentration of drug resistant strains of microorganisms in the hospital setting, and wide use of procedures and surgeries that increase the likelihood of infection (e.g. urinary catheterization, venipuncture, surgery, etc.). In many cases nosocomial infections are more difficult to treat due to the virulence of the pathogen and drug resistances.

Helix test

A rigorous performance test for steam penetration autoclaves. A helix test strip or digital device is “sterilized” in the autoclave as any object would be. The helix test strip or device determines if the pressures obtained during the sterilization cycle and the steam penetration were satisfactory. It provides autoclave users a way of documenting compliance with patient safety and sterility standards. Also known as a Hollow Load Process Challenge Device.

Hepadnaviruses

Enveloped, partially double and single stranded DNA viruses that cause hepatitis B in humans (hepatitis B virus) and ducks (duck hepatitis B virus). May also cause Primary Hepatocellular Carcinoma in susceptible individuals that possess certain comorbidities. Hepadnaviruses have relatively small genomes and are transmitted vertically (from mother to fetus) and direct blood transfusion (e.g. intravenous drug use or medical allogenic blood transfusion) from infected individuals.

Hepatitis A

An acute infection and inflammation of the liver caused by the hepatitis A virus. The hepatitis A virus is passed via the fecal-oral route which means that it is acquired by consuming the virus from infected feces. Common ways in which that occurs is through consuming raw food prepared in an unsafe manner by an infected person or through drinking water contaminated with infectious feces. Hepatitis A is an acute liver disease and is usually cleared fully by the immune system with little to no permanent liver damage. Visible symptoms (e.g. jaundice) first appear about four weeks after infection and subside by seven weeks.

Hepatitis A virus (HAV)

A non-enveloped, single-stranded, linear RNA enterovirus that is a member of the Picornavirus family. The virus is passed between humans via the fecal-oral route. Humans are the only reservoir for the hepatitis A virus. There is a vaccine that can reduce the risk of acquiring hepatitis A disease from the virus. Once humans are infected with hepatitis A virus and the immune system clears it, they have continued immunity against additional infections.

Hepatitis B

An infection and inflammation of the liver caused by the hepatitis B virus. Hepatitis B is both an acute and chronic liver disease -patients remain carriers even when they are asymptomatic. The liver inflammation from hepatitis B infection is due to the immune system’s response to the virus rather than direct viral cytotoxicity. Transmitted through contact with infected blood or bodily fluids. Late stage complications of chronic hepatitis B infection are cirrhosis of the liver and hepatocellular carcinoma.

Hepatitis B virus (HBV)

The hepatitis B virus is an enveloped, double-stranded DNA virus that is relatively resistant to extremes of temperature and humidity. The virus is passed from person to person mainly through transmission of contaminated blood, semen, and vaginal fluids or can be passed vertically from mother to fetus across the placenta. There is a vaccine available against Hepatitis B virus.

Hepatitis C

Chronic infection and inflammation of the liver that occurs in three-quarters of people infected with the hepatitis C virus. Eventually causes accelerated liver cirrhosis (especially with concomitant alcohol use/abuse), portal venous hypertension, and liver failure if not cleared or successfully treated. Contracted through blood contact and, less likely, sexual contact.

Hepatitis C virus (HCV)

Small, enveloped, single-stranded RNA virus of the Flavivirus family. HCV is closely related to dengue, hepatitis G, and yellow fever viruses. HCV has a very high replication rate without a molecular system to proofread transcription or translation and therefore has an extremely high mutation rate. It is transmitted through blood contact/mixing/transfusion. Sexual contact is a less common mode of HCV transmission.

Herpes simplex virus (HSV)

Enveloped, ubiquitous herpesviruses that cause human disease and are highly contagious through close contact. HSV causes red, painful, itchy lesions around the lips, mouth, genitals, and anus. The two main human HSV types are HSV-1 and HSV-2. Usually HSV-1 affects the oral mucosa while HSV-2 affects the genitals and anal region, but this is not strictly the case. Herpes simplex virus is neurotropic and retreats into a nerve ganglion where it remains dormant until reactivation. Treatment of HSV infections is not curative but aimed at preventing reactivation and managing symptoms.

Herpesviruses

Large, double-stranded DNA viruses with over 100 genes and a lipid envelope. Herpesviruses cause a number of important human diseases such as Herpes simplex (oral and genital herpes), Epstein-Barr, Kaposi’s sarcoma, and varicella zoster. Herpesviruses are transmitted in various ways included close contact, sexual contact, and respiratory droplets depending on the specific herpesvirus. Herpesviruses evade the immune system in several ways and in many cases cause a persistent and/or latent infection.

High level disinfectant

Disinfectant that reproduces almost, but not completely, the effective sterilization of a sterilant. High-level disinfectants destroy vegetative bacteria, mycobacteria (the agents that cause tuberculosis), fungi, viruses and spores. Chlorine, formaldehyde solution, glutaraldehyde and peroxides are common examples of high level disinfectants. High-level disinfection can also be achieved by immersion in boiling water or by applying steam following certain protocols.

High-level disinfectant

A disinfectant that nearly, but not fully, meets the sterilization efficacy of a sterilant. High-level disinfectants destroy vegetative bacteria, mycobacteria (the causative agent of tuberculosis), fungi, viruses and spores. Chlorine, formaldehyde solution, glutaraldehyde, and peroxide are common examples of high-level disinfectants. High-level disinfection can also be achieved by immersion in boiling water or steam application following certain protocols.

Hospital Acquired Infections (HAIs)

Infections that are contracted by patients during hospitalization. Also known as nosocomial infections and differentiated from community-acquired infections. Pathogenic organisms that commonly cause hospital-acquired infections include methicillin resistant Staphylococcus aureus and clostridium difficile

Hospital disinfectant

A classification defined and regulated by the Environmental Protection Agency (EPA) for low or intermediate level disinfectants that are used as germicides on nonporous surfaces in healthcare settings. Must have efficacy against Salmonella sp., Staphylococcus aureus, and Pseudomonas aeruginosa as well as tuberculocidal and virucidal activities. Hospital disinfectants must be used above certain minimum concentrations and for sufficient contact times in order to be effective.

Hospital disinfectants

A classification defined and regulated by the Environmental Protection Agency (EPA) for low- and medium-level disinfectants used as germicides on non-porous surfaces in healthcare facilities. They must be effective against Salmonella, Staphylococcus aureus and Pseudomonas aeruginosa and must perform virucidal and tuberculocidal activity. To be effective, hospital disinfectants must be used above certain minimum concentrations and for sufficient contact times.

Human immunodeficiency virus (HIV)

An enveloped retrovirus with two single strands of RNA that eventually causes Acquired Immunodeficiency Syndrome (AIDS). HIV has particular affinity/tropism for CD4 positive T cells. The virus is internalized by an immune system cell, replicates, and then destroys the cell. The destruction of T cells leads to a deficient immune system and allows opportunistic infections to affect the host. HIV is transmitted from person to person through sexual contact, blood exchange/transfusion or vertically (from mother to fetus).

Hydrogen peroxide

A chemical with oxidizing, bleaching, and antiseptic properties with the molecular formula H2O2. Peroxides are highly reactive oxygen species and can interfere with DNA and RNA. In fact, phagocytes use hydrogen peroxide in the destruction and digestion of microorganisms. Hydrogen peroxide has an advantage over other chemical disinfectants in that it spontaneously breaks down into oxygen and water.

Hygiene

In a clinical context, hygiene is the set of habits and practices that one uses to minimize infection or colonization of one’s self, the transmission of infectious agents to others, and the transfer of pathogenic microorganisms to objects.

Hygiene plan

A hygiene plan defines all measures aimed to infection control in accordance with legal requirements and international guidelines such as the recommendations by the Robert Koch Institute (RKI) for protection of patients, personnel, and third parties. These measures include code of behavior, regulations regarding protective equipment, disinfection, cleaning, and sterilization. In addition, the hygiene plan describes responsibilities of the individual and organization. Procedures, products etc. stated in the hygiene plan must be strictly followed and the plan is subject to regular revision in order to keep it up to date.

Hygienic hand disinfectant / Hygienic hand scrub

A liquid chemical, usually containing alcohol(s), iodine, or chlorhexidine that is used to remove potential pathogens from the surface of the skin on the hands. The type of hygienic hand disinfectant that is used depends on the medical indication however the overall goal is to reduce the spread of infectious agents through direct contact. Therefore, the effective spectrum of a hand disinfectant should at least include bacteria (including mycobacteria), fungi, and enveloped viruses such as the blood-borne HIV. Hygienic hand disinfectant is a primary defense against microorganisms that pass via the fecal-oral route when used in accordance with European standard EN 1500.

Hygienic hand disinfectant / hygienic hand scrub

A chemical liquid, usually containing alcohol(s), iodine or chlorhexidine, used to remove potential pathogens from the skin surface of the hands. The type of hygienic hand sanitizer used depends on the medical indications; however the overall goal is to reduce the spread of infectious agents through direct contact. Therefore, the efficacy spectrum of the hand sanitizer should include at least bacteria (including mycobacteria), fungi and enveloped viruses such as the blood borne virus of HIV. Hygienic hand sanitizer, when used according to the European Standard EN1500, is a primary defense against microorganisms that pass via the oral-faecal route.

Hygienic hand disinfection

Process of using an alcohol-based agent on the hands/forearms to kill or inactivate microorganisms on the skin via direct contact. This approach is able to provide higher antimicrobial efficacy than handwashing and causes less microbial aerosolization. It is used to remove the microbial flora of the skin between episodes of contact with a patient.

Hygienic hand disinfection

The process of using an alcohol-based agent on the hands/forearms to kill or inactivate microorganisms on the skin by direct contact. This approach achieves far superior antimicrobial efficacy than hand washing and causes less microbial aerosolisation. Used to remove skin microbial flora between episodes of patient contact.

Hygienic hand washing

Depending on geographic location, hygienic hand washing may range from simple debris removal to antimicrobial cleaning. In any case, the process involves a washbasin and the application of water. Hygenic hand washing does not provide the same antimicrobial efficacy as hygienic hand disinfection.

INCI

Acronym for International Nomenclature of Cosmetic Ingredients. Standardized nomenclature established by the EU Cosmetics Directive (76/768/EEC) for cosmetic product ingredient labelling.

Immersion disinfection

Process by which an object or device is completely submerged in a liquid disinfectant agent. Disinfection takes place in all areas that come into direct contact with the liquid. Immersion disinfection can only be performed on water resistant and non-electrical devices.

Immersion disinfection

Process by which an object or device is completely submerged in a liquid disinfection agent. Disinfection occurs at all points that make direct contact with the liquid. Immersion disinfection can only be used on waterproof or non-electrical devices.

Immunity

A state in which infection with a pathogenic microorganism is prevented due to a primed and vigilant immune system. Immunity can be achieved by primary infection and clearance by the immune system or through the use of a vaccine to stimulate immunity without the primary infection. Passive immunity is achieved from the injection of the appropriate antibodies derived from an external source. Unlike traditional immunity which is essentially life-long against a particular antigen, passive immunity is temporary.

Immunization

A means of causing immunity against a particular antigen (and subsequently a particular pathogen) by presenting that antigen to the immune system without causing an infection. Immunization is also referred to as vaccination since a vaccine is administer to prompt immunity. Strictly defined, a primary infection can affect immunization as well since the immune system clears the infection and retains immunity.

Incubation period

The time from infection with a pathogenic organism and the first appearance of signs or symptoms of disease. Patients may be and are often infectious to others during the incubation period.

Incubator

Medical devices that simulate and provide favorable environmental conditions for the living organism contained within it, from bacterial cultures to newborn humans. Users may be able to control temperature, relative humidity, and oxygen tension, among other parameters.

Indirect contact transmission

Transmission of an infectious agent from a contaminated surface or object (fomite) rather than through an infected person. Indirect contact is a route of transmission for microorganisms that can survive outside of the body without a reservoir. This transmission route generally requires that the person touches the contaminated surface with broken skin, mucous membranes, or later self-inoculate into one of these two areas. The Norwalk virus is an example of a microorganism that is hearty enough to be passed through indirect contact. Common examples of fomites in a medical setting are handles and handrails, stethoscopes, and bathroom surfaces.

Infection

The presence and multiplication of pathogenic microorganisms in a region of the body that is normally sterile or does not usually serve as a colonization site for that microorganism. An infection differs from colonization in that there are negative consequences for the organism that is infected; consequences ranging from local inflammation to mild symptoms to widespread and life-threatening disease.

Infection control

Medicines adopted to reduce the spread of pathogenic organisms from the infected to the non-infected. The infection control includes protocols for hand washing, as a minimum, combined with contact pads, pads relating to the protective clothing, sanitation procedures, disinfection measures, and residue handling protocols. The control of infections can also include maintaining the vaccines daily to eliminate the possible reservoirs of pathogenic microorganisms.

Infection control

Steps taken to minimize the spread of pathogenic organisms from the infected to the non-infected. Infection control includes hand washing protocols at a minimum along with contact guidelines, guidelines regarding protective clothing, isolation procedures, decontamination measures, and waste handling protocols. Infection control may also include maintaining current vaccinations to eliminate possible reservoirs for pathogenic microorganisms.

Infectious waste

Fluids, tissues, and the objects used to handle them that are infected with a potentially pathogenic microorganism. Blood and other body fluids as well are considered infectious waste since they can contain undetected pathogenic microorganisms. Dead humans, dead animals, and pieces of tissue not treated to destroy any microorganisms contained therein would be considered infectious waste. Because of the possible harm to those that come into contact with it, infectious waste must be handled cautiously and disposed of properly.

Inflammation

The collection of immune system cells in their activated state and the cytokines and intercellular signaling molecules generally called upon to fight infection. Often inflammation is a protective state in which the immune system detects and destroys foreign bodies or infectious microorganisms. Symptoms of inflammation include redness of the skin, swelling, calor (local warmth), and pain. The process of inflammation is not always advantageous as in autoimmune diseases, chronic inflammatory diseases, and in response to allergens.

Influenza

Name used to describe a number of related illnesses caused by one of the influenza viruses. Symptoms of the illness include upper respiratory and gastrointestinal complaints, ranging from moderate to severe. Influenza is highly contagious/transmissible. Serious infections in susceptible individuals may be lethal. Spread is minimized by meticulous hygiene, barrier protection, and immunization when available. Antiviral therapy may be indicated.

Influenza A virus

Along with B and C, influenza A virus is one of the three main types of viruses that cause human influenza. The enveloped Influenza A viruses are orthomyxoviruses and are divided into subtypes based on two surface proteins (H and N). Examples include H3N2 influenza and H1N1 influenza. Influenza A virus is transmitted from person to person or animal to person through respiratory droplets or direct contact and causes fever, fatigue, and breathing difficulties.

Inorganic acids

Molecules that readily give of a hydrogen ion that do not contain a hydrocarbon backbone. Common examples of inorganic acids are sulfuric acid, hydrochloric acid and nitric acid. Organic acids, by comparison, have a carboxylic acid functional group that acts as the proton donor (hydrogen ion).

Instrument disinfection

Disinfection of tools.

Instrument disinfection

Disinfection of instruments.

Instrument processing

Process and regulations governing the preparation, cleaning, disinfection, sterilizing, packaging, and storage of instruments. Separate requirements apply to critical (e.g., surgical instruments), semi-critical (e.g. dental impression trays), and noncritical items (e.g., blood pressure cuffs).

Instrument reprocessing

Process and regulations governing the preparation, cleaning, disinfection, sterilizing, packaging, and storage of instruments. Separate requirements apply to critical (e.g., surgical instruments), semi-critical (e.g. dental impression trays), and noncritical items (e.g., blood pressure cuffs).

Instrumentos transmisores

Describe instrumentos dentales mecanizados tales como turbinas, contra-ángulos y piezas de mano, en los que la energía de aire comprimido impulsa una transmisión de potencia a una fresa o una pieza giratoria. Los instrumentos de transmisión tienen varios lugares en los cuales los microorganismos pueden acumularse, y al ser utilizados en serie en los pacientes, requieren estrategias de esterilización precisas y eficaces.

Intermediate-level disinfectant

According to the Centers of Disease Control and Prevention (CDC), an intermediate-level disinfectant is a chemical germicide that kills enveloped as well as some non-enveloped viruses, yeast fungi, and bacteria and possibly mycobacteria if specifically denoted as a tuberculocide. Not able to kill all microorganisms or spores but is able to kill more microorganisms than a low-level disinfectant.

Invasive instruments

Medical instruments that penetrate the skin or enter a body cavity. Invasive instruments are considered to be critical items for purposes of processing/reprocessing.

Irritant contact dermatitis

A reaction of the skin leading to redness and swelling caused by direct contact with a chemical. Irritant contact dermatitis is a nonspecific immune reaction to a chemical irritant in contrast to allergic contact dermatitis, which occurs in people specially sensitized and immunologically responsive (allergic) to an allergen/antigen, usually also in the form of a chemical.

LC (Lethal Concentration)

Minimum concentration of a substance that is able to kill an organism. It is usually described in terms of exposure time (e.g., 70% ethyl alcohol is the lethal dose after 30 second of exposure time).

LD (Lethal Dose)

Dose of a substance or energy source that can kill an organism. Often expressed as LD50, or the dose that will kill 50% of organisms tested.

Latex allergy

A skin reaction that is caused by exposure to one of the components of natural rubber latex. Latex allergy has three components which may, but usually do not, occur in any single sensitized person: irritant dermatitis, delayed (type IV) hypersensitivity, and immediate (type I) hypersensitivity. In the general population, latex allergy occurs in as many as 5% of people and up to 20% in health care workers and those with repeated, heavy exposure to latex. The immediate (type I) hypersensitivity can be life-threatening if severe and untreated.

Legionella

Aerobic, Gram-negative, rod-shaped bacteria that are difficult to grow in culture which means that they often evade detection. Legionella requires cysteine in the growth medium in concentrations not typically present in bacterial growth media. Legionella can survive for long periods of time in aqueous environments and have been cultured from ventilation systems, pools, saunas, and water systems among others. Transmitted through aerosolized droplets from surfaces or respiration as well as contact with infectious materials. Legionella pneumophila is the causative organism of Legionnaires’ disease.

Legionnaires’ disease

Disease primarily affecting the lungs causing fever, muscle pain, and pneumonia. Caused by Legionella pneumophila, which was uncharacterized before an outbreak in 1976 at an American Legion function (hence the name). Susceptible populations include smokers, those over age 65, the immunocompromised, and those with chronic lung diseases. Legionella is responsible for Legionnaires’ disease and Pontiac fever; each is referred to as a legionellosis. Legionnaires’ disease can lead to several serious complications if not effectively treated with antibiotics.

Limited virucidal activity

A disinfectant that is able to inactivate some, but not all viruses with which it makes physical contact. Generally any limited virucidal disinfectant must list all the viruses on the label that are inactivated by the disinfectant. By some definitions a limited virucidal disinfectant is one that inactivates enveloped viruses while a virucidal disinfectant has activity against enveloped and non-enveloped viruses.

Lipid

A broad class of organic compounds, which contain a long hydrocarbon chain within their chemical structure. The class includes fats and oils, waxes, fat-soluble vitamins, phospholipids, and some detergents. Pure lipids (without hydrophilic components) are generally insoluble in water because of their hydrophobic chemical properties. In medicine, the term lipid is used to describe various lipoproteins of varying densities that carry fatty acids and cholesterol in the blood.

List for virucidal products (IHO)

Summary of virucidal hand, instrument, and surface disinfectants issued by the German Industrial Association for Hygiene and Surface Protection (IHO).

Listeria monocytogenes

Gram-positive bacterium, transmitted via contaminated food, that is responsible for the illness, listeriosis. Listeriosis causes flu-like symptoms and may cause meningitis or brain infection. The illness has a relatively high mortality rate and requires antibiotic treatment for an extended period.

Listeriosis

A disease process caused by infection with the bacterium Listeria monocytogenes. Usually contracted through the consumption of contaminated food and especially affects newborns, pregnant women, the elderly, and immunocompromised individuals. The clinical symptoms of Listeriosis depend on the age of the patient and the organ system affected by the infection. Symptoms of Listeriosis range from gastrointestinal distress to meningitis, seizures, and death.

Log reduction

Indicates that the number of microorganisms in a given location has been reduced by a factor of ten. A four log reduction would indicate a microbial reduction of 10,000-fold, for example.

Low level disinfectant

Chemical agent that kills some bacteria, yeasts and many enveloped viruses by direct contact. Low-level disinfectants are used in situations where intermediate or high-level disinfectants are not needed. A quaternary ammonium salt-based germicidal cleaner is an example of a low-level disinfectant.

Low-level disinfectant

A chemical agent that kills some bacteria, yeast fungi, and most enveloped viruses through direct contact. Low-level disinfectants are used in situations where intermediate-level disinfectants or higher are not required. A quaternary ammonium germicidal detergent solution is an example of a low-level disinfectant.

Lower respiratory tract infection

Any infection that includes the trachea, bronchi, or lungs. Examples include pneumonia and bronchitis. There is a high incidence of lower respiratory tract infections in patients who are being ventilated via endotracheal intubation.

MDD

Acronym for Medical Device Directive. European Directive (93/42/EEC) intended to harmonise the requirements governing medical devices across the EU with the overall goal of improving patient safety.

MNV (Murine norovirus)

Murine (mouse) norovirus; can be grown in cell culture. Murine norovirus is increasingly used as alternative to FCV, i.e. as surrogate virus for efficacy testing of disinfectants.

MPG

Medizinproduktegesetz or Medical Product Law that regulates the marketing of medical devices, replacing the German Medical Device Directive.

MRSA

Methicillin-resistant Staphylococcus aureus. Differentiated from native Staphylococcus aureus bacteria in that it is resistant to beta-lactam antibiotics (including methicillin, which is no longer used clinically). The bacterium can cause serious infections in various areas of the body (e.g., skin, endocardium, pulmonary tissue). MRSA is further subdivided into community-acquired and hospital-acquired since the respective infections have different clinical characteristics.

Material Safety Data Sheet (MSDS)

A collection of physical, chemical, and biological information as it relates to use, storage, handling and safety for each substance that is used in a given workplace. A collection of all relevant MSDSs is to be made freely available to all employees within the workplace.

Measles

A disease caused by the measles virus, an enveloped RNA virus of the Paramyxovirus family. Symptoms of measles include fever, cough, and unique dermatological manifestations such as rash and Koplik spots. Once infected, the patient has life-long immunity. Immunosuppression occurs with measles that can lead to bacterial superinfection.

Medical devices

Any item (including any instrument, apparatus, implant, substance or software) used to diagnose, treat, or provide support or therapy to a patient within a healthcare facility. According to the European Medical Device Directive 93/42/EEC, disinfectants are also considered medical devices. Medical devices are divided into critical, semi-critical and non-critical according to the level of contact and the degree of invasiveness. The classification is based on risk estimation and defines reprocessing requirements as medical devices require different levels of sterility depending on their use.

Medical devices

Any object (including instruments, apparatus, fixtures, substances, or software) that is used to diagnose, treat, or provide support or therapy to a patient in a healthcare setting. According to the European Medical Device Directive 93/42/EEC, disinfectants are also considered medical devices. Medical devices are divided into critical, semi-critical, and non-critical depending on the level of contact and degree of invasiveness. The classification is based on a risk assessment and defines the reprocessing requirements as medical devices require different levels of sterility depending on their use.

Medical devices of Group B

Semi-critical or critical medical devices that contain internal parts that cannot be visually inspected during routine use or without disassembling the device. These internal parts come into contact with the fluids that are potentially introduced to patients and therefore require special protocols and disinfection supplies. The medical devices of Group B with high reprocesamiento requirements include objects with tight hoses, glued to organs with complete or delicate surfaces, as well as fragile objects and transmission instruments.

Meningitis

An inflammation of the covering of the brain and spinal cord called the meninges. Meningitis may cause headache, sensitivity to light (photophobia), neck stiffness (nuchal rigidity), and changes in the cerebrospinal fluid detected by spinal tap (lumbar puncture). Meningitis may be acute or chronic and can be caused by viruses, bacteria, fungi, mycobacteria, and parasites. “Aseptic” meningitis is incited by a microorganism, usually a virus, but the pathogen does not create a pyogenic cellular reaction in the meninges.

Methicillin-resistant Staphylococcus aureus (MRSA)

Bacteria of the species Staphylococcus aureus that have acquired a stable resistance to methicillin and structurally related antibiotic drugs (e.g. amoxicillin, penicillin, and oxacillin). These bacteria are no longer affected by these antibiotics that were previously able to destroy them. MRSA is the prototypical drug resistant bacterium. MRSA has been divided into community-acquired and hospital-acquired (nosocomial) because they generally cause distinct skin infections, virulence patterns, and are killed by different classes of antibiotics.

Microorganisms

Living organisms that are too small to be seen with the naked eye and require the aid of a microscope. Bacteria and fungi are examples of microorganisms. Viruses and prions are nonliving and technically not microorganisms, however many people include viruses under the definition of microorganism.

Mid-level disinfectant

According to the Centers for Disease Control and Prevention (CDC), an intermediate-level disinfectant is a chemical germicide that kills enveloped and some non-enveloped viruses, yeast, bacteria, and in some cases mycobacteria, when specifically denoted as a tuberculocidal . It is not capable of killing all microorganisms or spores, but it is capable of killing more microorganisms than a low-level disinfectant.

Moisturizers

Substance that make the stratum corneum (outermost layer of the skin/epidermis) softer and suppler by increasing and retaining water content. Moisturizers are closely related to humectants and emollients though much less related to lubricants. Moisturizers typically provide a protective barrier allowing damaged skin time to repair itself before sustaining further injury.

Mouthwash

Liquid solution that is inserted into the oral cavity to rinse, and then subsequently expelled (it should not be ingested) in order to remove debris from the oral cavity, counteract bad breath and reduce pathologies. Not all mouthwashes are effective for their intended purpose; the FDA has divided mouthwashes into two categories: cosmetic and therapeutic. The main difference between the two classes is that the therapeutic mouthwash is able to treat or prevent some pathologies of the oral cavity.

Mucous membrane

Specialized tissue containing epithelium, lamina, and propria layers that lines certain structures in and on the body. Mucous membranes are synonymous with mucosa and secrete mucin. Mucous membranes do not confer the same barrier protection as the skin and may permit the passage of pathogens into sterile areas of the body, leading to infection. Mucous membranes cover many organ systems and tissues include respiratory, gastrointestinal, and urinary systems.

Mucous membrane antisepsis

Describes the processes and disinfectants that may be used on mucous membranes. Mucous membranes are sensitive structures and also entry points for microorganisms during medical procedures. Antisepsis in these areas needs to reduce the number of microorganisms and minimize the risk of infection without breaking natural physical barriers. PVP-Iodine and octenidine are common mucous membrane antiseptic agents.

Multi-drug resistant / multiresistant organism

A pathogen that is not killed, inactivated, or inhibited by several classes of antibiotics. A pathogen generally develops resistance to a single class of antibiotics thus any antibiotic with a particular mechanism of action is no longer effective. In multi-drug resistance or in the case of multiresistant organisms, antibiotics with different mechanisms of action are no longer effective. Infections with multiresistant organisms are very difficult to treat, clinically.

Multi-resistant bacteria

Bacteria that are resistant to bactericidal or bacteriostatic effect of more than one antibiotic. The resistance pattern of a given infectious microorganism is determined by assessing its susceptibility to various antibiotic classes in laboratory culture. Multi-resistant bacteria have the same susceptibility to chemical disinfectants as the wild type bacterium.

Mycobacteria

Aerobic, acid-fast, Gram-positive bacilli. The prototypical mycobacterium is Mycobacterium tuberculosis, which causes the human illness, tuberculosis.

Mycobactericidal activity

The capacity of a disinfectant to kill mycobacteria. Mycobactericidal efficacy testing of disinfectants is carried out in two stages. Tuberculocidal activity includes efficacy against Mycobacterium tubercuolosis, whereas mycobactericidal activity includes all mycobacteria. For proving mycobactericidal activity, European standards require in vitro tests (quantitative suspension tests; in the European Norms referred to as phase 2/step 1, e.g. according to EN 14348). According to the European Norm, the two test organisms required for claiming mycobactericidal activity are Mycobacterium terrae and Mycobacterium avium.

Mycobacterium tuberculosis

The mycobacterium responsible for the disease called tuberculosis (TB). Mycobacterium tuberculosis is carried on respiratory droplets and can remain aerosolized for relatively long periods of time. Transmission usually occurs through inhalation of infectious droplets and leads to elimination without disease, acute primary TB, accumulation and sustained dormancy/latency, or accumulation and reactivation at some later point. Mycobacteria are usually considered Gram-positive, however, they have a thick, characteristic cell wall, which is distinct in composition and renders them more resistant to the action of chemical disinfectants.

Non-critical Medical Devices

Any object that is used in the delivery of healthcare that may contact a person’s intact skin but does not touch mucous membranes or penetrate any body cavity, wound, or incision. Non-critical medical devices generally only require disinfection (not sterilization) since the skin acts as a protective barrier against transmission and infection.

Non-critical medical devices

Any item used in a healthcare facility that may contact a person's intact skin but does not touch membranes and does not enter any body cavity, wound, or incision. Non-critical medical devices generally require disinfection (not sterilization) as the skin acts as a protective barrier against transmission and infection.

Non-critical medical devices

Any object that is used in the performance of health care and that can be placed in contact with the intact skin of a person, but does not touch the mucous membranes or penetrate any cavity of the body, wound or incision. Non-critical medical devices generally only require desinfection (no esterilization) so that the skin acts as a protective barrier against transmission and infection.

Non-enveloped viruses

A virus that is comprised of genetic material and a capsid but lacks a glycoprotein shell called an envelope. As such the proteins on the capsid facilitate entry into cells. In general, RNA viruses that are not retroviruses are non-enveloped viruses. Non-enveloped viruses are usually lytic viruses. This means that they destroy the host cell after infection and replication. Examples of non-enveloped viruses include norovirus, adenovirus, and poliovirus.

Non-ionic surfactants

Surfactants are detergents with hydrophilic and hydrophobic poles. A non-ionic surfactant is one in which the hydrophilicity is achieved by a dipole or other chemical species that is stable/soluble in water. As such, non-ionic surfactants do not possess a charge. Non-ionic surfactants provide detergent activity regardless of the hardness of the water used.

Non-pathogenic

An entity that does not cause disease. This term is usually reserved for microorganisms that do not cause human disease and is differentiated from pathogenic organisms, which do. An example of a non-pathogenic microorganism is lactobacillus when it is in the gut. Lactobacillus can colonize the gut, prevent pathogenic bacteria from colonizing, and aid digestion. A non-pathogenic microorganism may become pathogenic if it moves into a different body compartment.

Norovirus

Single-stranded RNA, non-enveloped viruses previously called “Norwalk-like viruses” that are transmitted through the fecal-oral route. Norovirus is an important cause of acute gastroenteritis in humans producing symptoms such as diarrhea, vomiting, and stomach pain. Given the relative fragility of norovirus in the environment, most infections are thought to originate from food handlers immediately prior to food service.

Norovirus (Norwalk-like virus)

Non-enveloped RNA virus that commonly causes a severe gastrointestinal disease in humans. Norovirus is highly contagious and is primarily spread through faecal-oral contamination. Noroviruses are highly resistant to disinfectants.

Norovirus-Gastroenteritis

Viral illness that includes diarrhoea, projectile vomiting, fever, headache and fluid and electrolyte disturbances. The illness is contracted most commonly in the winter months and is spread via faecal-oral transmission. Norovirus is extremely virulent and the gastroenteritis is highly contagious.

Nosocomial infection

An infection that was not present or incubating at the time of admission to the hospital. Because of the large numbers of ill patients and the high frequency of antibiotic use in hospitals, nosocomial infections increasing result from antibiotic resistant strains. The incidence of nosocomial infections can be reduced by strict adherence to hygiene plans.

Notified body

An organization that is officially sanctioned (notified) by the European Commission to provide conformity assessments in accordance with New Approach Directives. Conformity assessments include inspection or testing depending on the circumstances. The goal of a notified body is to ensure standards represented by the CE marking are met or exceeded.

Organic

In chemistry, organic refers to a molecule that contains carbon within its structure with the exception of certain small, carbon-containing molecules (e.g. cyanide). In biology, organic refers to something that once was or still is capable biological decay or decomposition. Because organic matter is derived from previously living organisms, it contains high amounts of organic compounds.

Organic acids

An organic molecule that easily and readily donates a proton (hydrogen ion) to the solution. Most organic acids have at least one carboxylic acid functional group (shown). While the carboxylic acid functional group is always the same, the nearby atoms and overall structure of the molecule determine the acidity and related properties of the organic acid. Sulfonic acids (-SO2OH) when part of a larger organic compound may also be considered organic acids.

Pandemic

Occurs when geographically disparate peoples are infected with the same pathogen. A pandemic is differentiated from an epidemic in that a pandemic affects people on more than one continent. The distinctions between disease outbreak, epidemic, and pandemic were more relevant when international and intercontinental travel was less common and took longer to accomplish.

Papillomavirus

Papillomaviruses are a diverse group of non-enveloped DNA viruses containing double-stranded DNA that can cause a variety of animal and human diseases. Certain types of the human papillomavirus (HPV) have been linked to cervical cancer and related genital cancers while others are associated with genital warts.

Papovaviridae

Former name of a family of viruses that included papillomaviruses and polyomaviruses.

Parvovirus

Non-enveloped, single-stranded DNA virus that is mostly a cause of disease in animals but do cause disease in humans. History of infection and immunity is very common and most adults carry an antibody directed against the pathogen, which indicates previous infection and passage of the virus. Parvovirus B19 causes several clinical syndromes and complications, most notably Fifth disease. Parvovirus is responsible for particularly severe cardiac and gastrointestinal disease in dogs.

Pathogen

Any agent that is capable of producing disease or illness. The term is generally reserved for bacteria, viruses, fungi and other microorganisms that cause disease through infection. In this context, a pathogen is distinguished from microorganisms that do not cause disease (e.g. colonizing bacteria; non-pathogenic). Infectious diseases are caused by pathogens.

Pathogenic

Capable of producing disease or currently causing disease. Most bacteria are non-pathogenic and are not capable of causing disease but some are capable of causing disease if certain conditions are met. For example, Streptococcus species that colonize certain regions of the skin are potentially pathogenic but do not necessarily cause disease if living on unbroken skin. In the event the skin is broken and the Streptococcus infects the skin, cellulitis may result and the bacteria are pathogenic. Lactobacillus is not pathogenic, even when lining the wall of the colon.

Pathogenicity

The ability of an organism to harm the host or cause disease. The term pathogenicity is generally reserved for the inherent ability of a pathogen to cause disease rather than a dependence on external circumstances (i.e. opportunistic pathogens). Intrinsic factors that microorganisms possess that contribute to their overall pathogenicity include biological structures that help them move, penetrate tissue, and evade immune system defenses. An important factor of pathogenicity is the ability to produce toxins.

Peracetic acid

Organic acid with the chemical formula CH3-COOOH that is a synthesis of acetic acid and hydrogen peroxide. It is commonly used as a disinfectant in food and medical industries. The antimicrobial activity of peracetic acid rests mainly in its action as a strong oxidizing agent, allowing it to destroy cell membranes and thereby cause the destruction or inactivation of every type of microorganism.

Persistent infection

Infection with a pathogen that resists elimination by the immune system without some form of treatment. Viruses are the best known agents for causing persistent infections and some, such as hepatitis C and human immunodeficiency virus, are usually never fully cleared from the body after primary infection. Certain bacteria can also cause persistent infections such as syphilis. There are a variety of ways in which a persistent infection can occur; many involve evasion, concealment, or manipulation of the person’s immune system.

Personal Protective Equipment (PPE)

Devices that a subject wears to prevent injury or infection from external invective. The type of personal protective equipment varies according to the potential risks in a given environment. PPE may include masks, gloves, gowns, goggles, or full body armor. The equipment is designed to specifically protect the wearer. This is unlike the equipment used during a surgical procedure, for example, which is specially made to prevent infection in the patient.

Personal protective equipment (PPE)

Equipment that a person wears to prevent injury or infection from external insults. The type of personal protective equipment varies depending on the potential risks in a given local environment. PPE may include masks, gloves, gowns, goggles, or complete body coverings. The equipment is designed to protect the wearer, specifically. This is in contrast to equipment used during surgery, for example, which is designed to prevent infection in the patient.

Phenols

Organic molecules that contain, at a minimum, a six-member aromatic carbon ring with one hydroxyl group (-OH). The simplest phenol, shown in the figure, is used as a disinfectant as are several other phenols such as 2-phenylphenol and dimethylphenol (Xylenol). Phenols are reducing agents (antioxidants) and may cause adverse health effects. Phenol applied to equipment may leave a residue, which limits its use as a cleanser and disinfectant for some applications.

Physical sterilisation

Method to inactivate or remove microorganisms by physical (rather than chemical) means such as filtration, heat, or radiation.

Pneumonia

An inflammation of the alveoli of the lungs that tends to consolidate and produce inflammatory cells and secretions into the airway. Pneumonia is usually caused by an infectious agent (e.g. bacteria, viruses, mycobacteria, fungi, etc.) but may occur after the inhalation of certain chemicals; however chemical inhalation leading to lung inflammation is often called pneumonitis.

Poliomyelitis

A viral illness that affects the motor neurons in the spinal cord and brain stem commonly known as polio. The lack of neuronal innervations and muscular activity leads to a profound atrophy of the muscles normally innervated by these motor neurons. Once contracted, there is no effective treatment other than supportive care. The disease can be eradicated through proper immunization and has been eliminated as a disease from most countries throughout the world.

Poliovirus

Small single-stranded, non-enveloped, RNA enterovirus of the Picornavirus family which causes poliomyelitis in about 5% of people infected. The vast majority of infected patients have few or minor symptoms. Vaccination against poliovirus has all but eradicated poliomyelitis throughout the world. Poliovirus is transmitted via the fecal-oral route. Poliovirus is highly resistant to physical and chemical impacts. Due to its intrinsically high resistance to disinfectants, poliovirus usually serves as a test virus to determine whether a disinfectant is fully virucidal.

Polyomavirus

Small, non-enveloped DNA viruses that are an important cause of human disease. One notable example is the human papillomavirus, responsible for genital warts and cervical cancer. Polyomavirus (SV 40) is used as a test virus for disinfectant virucidal efficacy testing.

Post-exposure prophylaxis

Steps taken to prevent further spread or proliferation of an infection after a person has been exposed or inoculated to a pathogen. The prototypical example of post-exposure prophylaxis is the administration of antiretroviral medications to someone that has suffered an accidental needle stick with HIV-contaminated blood. The type, dose, and duration of prophylactic treatment are usually less than treatment doses. Post-exposure prophylaxis is done with the intent of preventing an infection from taking hold within the body and eliminating it before it leads to full blown disease.

Practice testing

European Norm methodology for testing disinfectants for the use in clinical medicine, using practical testing conditions. For example, EN 12791 describes surgical hand disinfection as it may be used in a hospital setting.

Prevention

Describes the prophylactic actions taken to prevent the occurrence or recurrence of disease. In infectious disease, this may include steps to minimize the spread of pathogenic microorganisms.

Prions

Unique, poorly understood human and animal pathogens that cause spongiform encephalopathies such as Creutzfeldt-Jakob disease and bovine spongiform encephalopathy (mad cow disease). Prions are transmissible, proteinaceous, non-living entities that appear to affect specific proteins within the brain of affected individuals. Prions are unique among infectious agents in that they apparently can be inherited.

Protective clothing

Apparel worn to prevent or reduce the likelihood of injury, infection, or exposure. The construction and materials used in protective clothing vary depending on the expected insults in the environment. Protective clothing can be used to protect against physical trauma, extremes of temperature, radiation, chemical or biological agents, or any other environment that is hazardous to health.

Protein

A polymeric macromolecule that is composed of amino acid monomers connected by peptide bonds (shown). A protein is distinguished from a peptide in that proteins contain more than 20 (or 50) amino acids. Proteins acquire certain properties based on their primary (amino acid sequence), secondary (cross-links), tertiary (three dimensional structure and folding), and quaternary (interaction with other proteins) structures. Proteins perform a large number of functions acting as structural elements, enzymes, and recognition devices, among many others.

Protein denaturation

Irreversible disruption of a protein’s quaternary, tertiary, secondary, and/or primary structure that removes its enzymatic activity. Denaturation may be caused by heat, acid, cross-linking or other processes.

Protein error

Reduced efficacy of disinfectants when used on objects or surfaces with excessive free protein. The protein on the surface essentially “buffers” or “weakens” the disinfectant so that it cannot destroy or inactivate microorganisms at equal concentrations. Cleaning excess protein prior to disinfection may reduce protein error.

Protein fixation

Process of protein inactivation in some way, generally by chemically creating crosslinks between various amino acids within the protein. Protein fixation is one way to prevent autolysis in a tissue or cell by rendering the proteolytic (protein-digesting) enzymes non-functional. Formaldehyde/formalin is an example of a protein fixative.

Pseudomonas

Gram-negative proteobacteria that comprise dozens of species within the pseudomonad family of bacteria. Depending on the species and strain, Pseudomonas can be innocuous to humans, an opportunistic pathogen, a biocontrol agent, or a bioremediation agent. The most common human pathogen of the genus is Pseudomonas aeruginosa. Pseudomonas aeruginosa can involve any part of the human body and is seen in patients with reduced immune defenses. Pseudomonas sp. produce antibacterial agents with activity against other (usually Gram-positive) bacteria.

pH

A dimensionless quantity that describes the amount of hydrogen ions in a solution. Since pH is based on an inverse logarithmic scale, the lower a pH value, the higher the acidity or hydrogen ion concentration is in that solution. Pure bleach and ammonia have high pH levels and are therefore basic. On the other hand, concentrated hydrochloric acid has a very low pH value. Normal pH values range from 0 to 14 and pure water at room temperature has a pH of 7.

pH-value

The logarithmic concentration of hydrogen ions in a solution. Solutions with a pH less than 7 have a higher concentration of hydrogen ions and are acidic. A pH of 7 is neutral and solutions with a pH greater than 7 are alkaline or basic.

Quaternary ammonia compounds (QAC)

Positively charged ammonium ions with four substituents. Quaternary ammonia compounds (QAC or quats) can be used as antimicrobials and disinfectants. By means of their positive charge quats interact with negative charges on the surfaces of bacteria, viruses, and fungi. The quats subsequently accumulate in the cell membrane, resulting in membrane damage, cell leakage, and eventual death of the microorganism or inactivation of the virus, respectively. While active against various bacteria, fungi and some viruses, these compounds do not kill or inactivate endospores, non-enveloped viruses, or Mycobacterium tuberculosis. As disinfectants, quaternary ammonia compounds may be inactivated by hard water and organic compounds and thus must be used in quantities and concentrations that overcome this inactivation.

Quaternary ammonium compounds

Positively charged ammonium ions with four substituents. Quaternary ammonium compounds can be used as antimicrobials and disinfectants. By means of their positive charge they interact with the negatively charged surfaces of bacteria, viruses and fungi. As a result, they accumulate in the cell membrane damaging it, causing the cell to leak out and possibly causing the death of the microorganism or the inactivation of the virus, respectively. While active against various bacteria, fungi, and some viruses, these compounds do not kill or inactivate endospores, unenveloped viruses, or Mycobacterium tuberculosis. As disinfectants,

REACH

Acronym of for Registration, Evaluation, Authorisation and Restriction of Chemicals. Ensures a high level of human and environmental protection from the risks of chemicals. Responsible for providing chemical safety information.

RKI / DVV guidelines

Guidelines, protocols, and regulations devised and recommended by the Deutschen Vereinigung zur Bekämpfung der Viruskrankheiten e.V (DVV; German Association for the Control of Viral Diseases) and the Robert Koch Institute (RKI). DVV is focused primarily on the detection, control, and inactivation of viruses along with viral vaccine development and administration. RKI is more broadly focused on concepts of infectious disease control. Disinfectants and related products that meet RKI / DVV guidelines represent a predictable and verifiable level of quality and effectiveness.

RKI list

List of disinfectants and disinfection procedures used for officially ordered decontaminations in accordance with Art. 18 IfSG. All disinfectants and disinfection procedures included in this list were tested for their efficacy by the Robert Koch-Institute (RKI) and for their safety with respect to human health and the environment by the German Federal Environmental Agency (UBA). The RKI list is different from the VAH list in several important ways.

Recirculation current

Recirculation has different definitions depending on the context, however in dentistry it refers to fluid extracted from a patient through suction devices which will subsequently be re-inserted into the mouth of the same patient or another. This can lead to the transmission of pathogens within the recirculating liquid. Recirculation can be avoided / greatly reduced through disinfection and proper use of the suction device.

Reflux

Reflux has various definitions depending on the context, however in dentistry it refers to liquid extracted from a patient with a suction device that is subsequently returned to the mouth of either the same patient or a subsequent patient. This can lead to the transmission of pathogens in the liquid that has been refluxed. Reflux can be avoided/greatly reduced through adequate disinfection and proper use of the suction equipment.

Remanence effect / Residual effect

Disinfection that continues beyond the immediate effect of the agent. A practical example of the remanence or remament effect is the on-going antimicrobial effect of surgical hand disinfection after applying latex gloves. It reflects an agent’s ability to continue to kill microorganism after initial application.

Resident skin flora

Normally non-pathogenic microorganisms that colonise cover the surface of the skin physicially displacing and siphoning metabolic resources from pathogenic bacteria. Resident skin flora participate in a commensal arrangement with humans. Perhaps the most abundant example is Staphylococcus epidermidis.

Resistance

The capacity of microorganisms to withstand environmental influences, physical or chemical inactivation procedures, or antibiotics.

Resistance

The ability of an organism to adapt to and defend against insults. One form of resistance is the changes made by organisms in response to exposure to a chemical or biological agent aimed at destroying them (e.g. bacteria to antibiotics, insects to pesticides, weeds to herbicides, etc.). Resistance may be inducible and temporary or a stable mutation that is passed on to progeny. The immune system also provides resistance to insults through detection, eradication, and “memory” of the insult

Rhinoviruses

Small, single-stranded, non-enveloped RNA viruses that are part of the picornavirus family. Rhinoviruses cause upper respiratory symptoms in humans such as runny nose, mild fever, watery eyes, and sneezing. In sensitive individuals rhinoviruses exacerbate asthma, cystic fibrosis, and chronic bronchitis. Rhinoviruses are transmitted through direct contact or aerosolized droplets from an infectious person with mucous membranes of the newly infected person.

Risk assessment

In healthcare settings, procedures that evaluate all objects, devices, and surfaces for their level of potential contamination and the steps required to ensure disinfection or sterilization in an effort to prevent the transmission of microorganisms and subsequent infection. A risk assessment includes information on how often to disinfect, when to do so, and what methods are to be used. The degree of patient contact and invasiveness is considered as well as the level of disinfection up to complete sterility. Recognized definitions of non-critical, semi-critical, and critical medical devices are used but are sometimes more stringently applied in certain clinical settings depending on individual needs

Robert Koch Institute (RKI)

German federal institution responsible for disease surveillance, control and prevention, particularly infectious diseases. RKI provides testing, educational materials, and also performs extensive amounts of disease research. The Robert Koch Institute is one of the oldest biomedical research foundations in the world named after the Nobel Laureate who is considered to be one of the fathers of microbiology.

Rotavirus

Non-enveloped, double stranded RNA virus of the Reovirus family primarily transmitted via the fecal-oral route (respiratory transmission may occur). Significant global cause of gastroenteritis in children which causes vomiting, watery diarrhea, dehydration, and death in some instances. Rotavirus can release a toxin that destroys enterocytes (intestinal cells) and cause malabsorption. There has been a vaccine against rotavirus available since 2006.

Rubella

Single-stranded RNA virus in the Togavirus family with a nucleocapsid and a lipoprotein envelope. Rubella virus is rapidly inactivated by 70% alcohol, formalin, chlorine, deoxycholate, beta-propiolactone, ultraviolet light, extreme pH and temperature but is resistant to thimerosal. Causes a mild, red rash when children are directly infected by can cause horrible birth defects if transmitted from mother to unborn fetus.

SARS

Severe acute respiratory syndrome believed to be caused by the SARS-associated coronavirus. SARS begins with flu symptoms but may progress to pneumonia, respiratory failure, and death. The coronavirus that causes SARS is passed from one of several reservoirs including poultry and small animals through close contact and droplets. Most SARS illness has been confined to China.

Salmonella

Gram-negative, rod-shaped enterobacteria with the ability to move using a flagellum. Salmonella is primarily acquired by consuming contaminated meat—typically beef, eggs, and poultry. In fact, Salmonella is a leading cause of food-borne illness. Salmonella species and strains cause three major human diseases: Typhoid fever, non-typhoid enterocolitis, and non-typhoid focal disease.

Semi-critical medical devices

Semi-critical medical devices are surgical devices and instruments that come into contact with mucous membranes and tissues without the protective barrier of the skin. They differ from critical medical devices in that they are not intended to traverse sterile compartments of the body or pass through tissue barriers. Examples of semi-critical medical devices are the endoscope, laryngoscope, endotracheal tubes and urinary catheters. Reprocessing of semi-critical medical devices requires at least high-level disinfection with a bactericidal, tuberculocidal, fungicidal, virucidal, and sporicidal chemical.

Semi-critical medical devices

Semi-critical medical devices are quirurgical devices and instruments that touch the mucous membranes and tejidos without the protection of the skin barrier. If they differ from the critical medical devices in which they are not hechos to go through the esthetic body compartments or pass through the tissue barriers. Examples of semi-critical medical devices are flexible endoscopes, laryngoscopes, endotracheal tubes and urinary catheters. The reprocessing of semi-critical medical devices requires at least a high level disinfection with tuberculosis, fungicide, bactericide, virucide and esporicide chemical products.

Semi-critical medical devices

Semi-critical medical devices are surgical devices and instruments that touch mucous membranes and tissues without the barrier protection of the skin. They are differentiated from critical medical devices in that they are not meant to cross into sterile body compartments or pass through tissue barriers. Examples of semi-critical medical devices are flexible endoscopes, laryngoscopes, endotracheal tubes, and urinary catheters. Re-processing of semi-critical medical devices requires at least high-level disinfection with a bactericidal, tuberculocidal, fungicidal, virucidal, and sporicidal chemical.

Sepsis

Eine schwere, körperweite Entzündung als Ergebnis einer ausser Kontrolle geratenen Infektion, für gewöhnlich bakteriell und entstanden üblicherweise aufgrund der Mikroorganismen, die in die Blutbahn gelangen. Sepsis verursacht Hypotonie durch verringerten Widerstand der peripheren Gefässe, Fieber, Unbilden (von Gram-negativen Bakterien) und kann ohne sofortige Behandlung fatal sein. Sepsis kann sich auch auf einen Zustand beziehen, der das Gegenteil von Asepsis ist, d.h. Mikroorganismen enthält.

Shelf life

The time that a product can be stored in its original packaging, unopened without disintegrating to a point below minimum standards. For food, the shelf life would be the length of time until the product changes color, flavor, texture, or has unsafe numbers of microorganisms.

Silent infection

An infection that does not cause grossly discernable symptoms. In a silent infection, evidence of the infection (e.g. microorganisms, antibodies against the microorganism) may be detected on a screening test or inadvertently discovered as part of an unrelated medical workup. Sexually transmitted diseases such as syphilis, Chlamydia, and even HIV can exist without outward manifestations (i.e. as silent infections) for some time.

Smallpox

Acute, contagious illness caused by an enveloped, double-stranded DNA virus, the Variola virus, which is a member of the poxvirus family. There are two main varieties of smallpox infection that differ in severity and, if one variety is acquired, immunity is developed against both. Smallpox is transmitted through virus-containing droplets that carry through the air and land on mucosa of the upper respiratory system. This transmission usually occurs through unprotected face-to-face contact. Smallpox first causes fever with head and backaches followed by a distinctive rash and pustular eruptions, which often leave characteristic scars. Vaccination has eradicated the disease.

Smear infection

Pathogens acquired through direct contact with an infected person or contaminated objects.

Sore

Indicates any abnormal opening in the skin but is usually reserved for descriptions of wounds and ulcers. Many pathogens can lead to the formation of sores, (e.g. herpes simplex 1 and cold sores; or Iimpetigo caused by Staphylococcus aureus). The deficiency in the skin or mucosa can result directly from the microorganism, from a toxin that it produces, or the body.

Spores

A reproductive structure that has features that enable it to withstand harsh environments. Spores generally have thick, relatively impervious outer walls that protect the reproductive molecular machinery inside. Once more suitable environmental conditions exist, the spore gives rise to progeny. Spores may simply be the means by which some microorganisms reproduce or they may be formed by certain species of bacteria, fungi, protozoa, and plants in order to survive unfavorable conditions. Spores are generally resistant to most forms of chemical disinfection and require more stringent measures, such as steam sterilization in an autoclave or a sporicidal, high-level disinfectant.

Sporicidal activity

An disinfectant that possesses the capacity to inactivate bacterial and fungal spores. Spores are generally highly resistant to insults and can persist in the environment under unfavorable conditions for extended periods. For proving sporicidal efficacy of disinfectants, European standards require in vitro tests (quantitative suspension tests; in the European Norms referred to as phase 2/step 1). To date, the only European test method is designated for the food industry (EN 13704). According to the European Norm, the test organisms for a sporicidal activity claim are spores of Bacillus subtilis, Bacillus cereus and Clostridium difficile.

Sporicide

Any chemical agent that can kill spores. Spores are heartier entities than the actively growing and dividing microorganism (vegetative cell) thus sporicides must create an extremely harsh local environment. Most disinfectants do not meet the definition of a sporicide since they cannot kill all spores.

Spray disinfection

The process of applying a chemical disinfectant using a dispenser that disperses the substance in the form of a vapor or spray. The advantage of spray disinfection is that it distributes the chemical over a large area, without complete immersion or use of external objects. However, spray disinfection is not appropriate in all cases because there may be areas that the disinfectant does not come into contact with. Spray disinfection is generally appropriate for non-porous surfaces prior to high-level disinfection. The spray creates aerosol particles containing the chemical and which may cause allergies, skin or respiratory tract irritation. To minimize this risk, spray disinfection should be limited to areas not accessible for normal disinfection.

Spray disinfection

The process of applying a chemical disinfectant using a nozzle that disperses the disinfectant into a mist or spray. The advantage of spray disinfection is that it can deliver the disinfectant over a large area without complete immersion or the use of external objects. However, spray disinfection is not appropriate in all instances because there may be areas where the disinfectant does not contact. Spray disinfection is generally appropriate for non-porous surfaces prior to higher level disinfection. Spraying creates aerosols containing chemicals originating from the disinfectant, which may be the cause of allergies, irritation of the skin or respiratory tract. In order to minimize this risk, spray disinfection should be limited to areas that are not accessible for wipe disinfection.

Standard methods of the DGHM

Methods to demonstrate the efficacy against bacteria and fungi of chemical disinfectants used in clinical medicine. Detailed in European Norms (EN) documentation.

Staphylococci

Gram-positive cocci that form “grape-like” clusters. Depending on the species, number of microorganisms, and location on or in the body, Staphylococci may be beneficial colonizers, commensal or pathogenic. Antibiotic-resistant Staphylococci (especially S. aureus) are a growing problem in healthcare and community settings.

Staphylococcus aureus

Facultatively anaerobic, coagulase-positive, Gram-positive cocci that exists as clusters of individual microorganisms. Staphylococcus aureus produces various toxins and causes a number of important diseases in humans including sores and abscesses, impetigo, infective endocarditis, toxic shock syndrome, scalded skin syndrome, among others. During the last decades, methicillin-resistant Staphylococcus aureus (MRSA) strains have emerged, rendering treatment of Staphylococcus aureus infections with antibiotics of the Beta-lactam family, which includes oxacillin and methicillin, ineffective. MRSA are nowadays one of the leading causes of nosocomial infections.

Steam sterilization

A technique that uses vaporized water to destroy microorganisms and spores on an object. Steam coagulates the proteins on the microorganism’s cell wall, envelope, capsid, etc. in contrast to dry heat, which incinerates or oxidizes. Steam sterilization is most often performed in an autoclave so that the steam can cover and penetrate the objects being sterilized. The autoclave is also used to apply pressures other than atmospheric. The steam used in steam sterilization should be free of solid, liquid, and vapor impurities.

Sterilant

A chemical that is capable of destroying or inactivating all microbial life, including endospores and viruses, with which it makes direct contact. It has a broader antimicrobial power than high-level disinfectants.

Sterile

An object, environment, or condition that is completely without microorganisms, active viruses, or spores. Since microorganisms are carried on dust particles, an environment is only sterile as long as it is dust-free and not touched or otherwise contaminated by microbes.

Sterilization

The process by which objects, surfaces, or liquids are made free of microorganisms, viruses, and spores. Sterilization can be achieved by various methods (e.g. steam, chemical contact, heat, etc.) however the method creates a hostile environment for the microbe. Sterilization may leave the surface or object with fragments of the microbe, but the remaining substance has been destroyed to the point that it cannot function or reproduce.

Sterilizers

Devices with chambers into which objects can be placed and be made sterile. The mechanism by which sterilizers achieve sterility varies by device type. The most common sterilizers use steam, gas (e.g. ethylene oxide), dry-heat, ultraviolet radiation, ionizing radiation, filtration, or gas plasma.

Streptococci

Gram-positive, catalase-negative, facultatively anaerobic cocci that occur in pairs (diplococci) or chains. Streptococci colonize much of the skin’s surface and can be non-pathogenic, opportunistic pathogens, or pathogenic depending on the species. Some clinically important Streptococci are Streptococcus pneumonia, Streptococcus pyogenes, and Streptococcus viridians. Streptococci cause a number of human diseases ranging from pharyngitis to meningitis.

Surface barrier

A physical separation between a clean or sterile environment and potentially infectious/pathogenic microorganisms. In order to achieve its intended purpose, a surface barrier must not allow pathogens to pass from one side of the barrier to the other (i.e. it has to be impermeable). Surface barriers may be used to protect surfaces that cannot tolerate repeated chemical disinfection, a disposable covering is meant for use during a single patient interaction, or to cover devices that may internalize and accumulate microbes.

Surface disinfection

Killing or deactivating microorganisms on surfaces (e.g. bedside tables, bed rails).

Surface disinfection

Killing or inactivating microorganisms on surfaces (e.g., bedside tables, bedrails).

Surfactants

Substances that lower the surface tension of liquids, effectively acting as detergents, wetting agents, and/or emulsifiers. Surfactants may be anionic, non-ionic, amphoteric, or cationic. Surfactants are often used in surface and instrument disinfectants.

Surgical Hand Sanitizer / Surgical Hand Scrub

An agent capable of providing a high level of disinfection to a surgeon's hands before performing a surgical operation. Ideally, the agent should be able to remove pathogens from the skin of the hands and wrists without being caustic or damaging the skin with frequent use. Common preparations contain alcohol, iodine, or chlorhexidine solutions. A surgical hand sanitizer should be effective against bacteria (including mycobacteria), fungi and viruses and comply with the European standard EN 12791.

Surgical hand disinfectant / Surgical hand scrub

An agent that is capable of providing a reasonably high level of disinfection to a surgeon’s hands for purposes of surgery. Ideally, the agent must be able to remove pathogens from the skin of the hands and wrists without being caustic or overly damaging to the hands with repeated use. Common preparations include alcohol, iodine, or chlorhexidine solutions. A surgical hand disinfectant should be efficacious against bacteria (including mycobacteria), fungi, and viruses and comply with European standard EN 12791.

Surrogate virus

A virus that possesses physical and chemical similarities to a pathogenic virus that is used for disinfectant testing yet is less dangerous to personnel and/or replicates more efficiently in vitro than the pathogenic virus.

Surrogate virus test

A test that is used to determine the virucidal activity of a potential virucide. Instead of a virus that for example cannot be cultivated a surrogate virus, (i.e. a virus that has similar shape, hydrodynamic size, composition, and stability of human pathogenic viruses, is used.)

Suspension test

Quantitative test that determines a disinfectants ability to reduce the number of microorganisms in terms of log factor. The term suspension indicates that testing takes place in aqueous and organic solutions.

Symptomatic

Experiencing detectable abnormalities in function as a direct result of a disease, disorder, or infection. Symptoms are subjective and based on the experience of the patient as opposed to “signs” which are abnormalities that are observed by someone else.

Systemic

Affecting most or the entire body rather than being localized to one limb, organ, or area of the skin. A systemic infection is one in which pathogens have travelled through the blood stream potentially seeding and infecting remote tissues and organs.

Terms of cleaning

Level of organic load present during a disinfectant test. Indicates an application in which the surfaces of an object have a sufficiently low presence of organic material. An organic load of 0.3% albumin is often used to simulate cleaning conditions.

Test viruses

Viruses that are used to determine virucidal activity of disinfectants. Examples include adenovirus, poliovirus, polyomavirus, and vaccinia virus. Test viruses are physically and chemically similar to the pathogens they represent and are selected to be at least as resistant as the native virus for testing purposes.

Tetanus

Infection and illness caused by a mobile, spore-forming, anaerobic, Gram-positive bacterium called Clostridium tetani, specifically from the toxin that it produces called tetanospasmin. Tetanospasmin has an affinity for neurons (nerve cells), and binds irreversibly, and blocks the release of neurotransmitters. Neurotransmitter blockade in the upper motor neurons leads to the characteristic skeletal muscle rigidity, which earned tetanus the name “lock jaw.”Clostridium tetani is found in the environment and in the gastrointestinal tracts of as many as a quarter of the population . Toxin synthesis and release requires certain environmental conditions, ideally a skin wound in humans .

Thermal and chemothermal procedures

Processes by which bacteria, viruses, fungi, and spores are destroyed or inactivated either by heat (thermal) or a combination of chemical exposure and heat (chemothermal). Thermal and chemothermal procedures may denature, oxidize, or incinerate pathogens depending on the structure and properties of the microorganism and the procedure used.

Thermal disinfector

A device that disinfects objects placed inside it through exposure to heated water and/or steam. Provides superior disinfection to solid object ultrasonic devices without vents although no disinfection method is effective for high-level sterilization/disinfection.

Thermal disinfector

A device that disinfects objects placed inside by sustained exposure to heated water and / or steam. Provides superior disinfection compared to ultrasonic cleaners for non-hinged, solid objects though neither disinfection method is effective for high-level disinfection/sterilization.

Toxins

Substances formed by microorganisms, plants, and animals that can cause disease or death in humans. Toxins are usually small molecules or peptides/proteins that are synthesized and released from the toxin-producing organism. Since they are non-living molecules, toxins cannot be killed and must therefore be denatured, incinerated, or otherwise inactivated to prevent human disease. There are various modes of entry, ranging from casual contact to oral consumption to venomous bites. Initial infection is often required before microorganisms will release toxin, but this is not always the case.

Transient flora

Bacteria, usually non-pathogens or opportunistic pathogens, that are present on human skin or mucosa for a certain period of time (hours to weeks) and are then displaced, destroyed, or stop reproducing. Transient microbes tend to be easily transferred between surfaces, objects, and skin. Antiseptic cleansing of the hands is aimed at destroying transient flora.

Transmission instruments

Describes mechanized dental instruments such as turbines, contra-angles, and handpieces in which the energy of compressed air drives a transmission to power a bur or rotary piece. Transmission instruments have various places in which microorganisms can seed and are used serially on patients, thus they require precise and effective sterilization strategies.

Transmission paths

The route by which humans become carriers or infected with a pathogen. The route of transmission may be through droplets, contact, blood/fluid exposure, or ingestion of contaminated food/water. Droplet transmission often requires inhalation of infectious material. Contact transmission may include direct inoculation of eyes or mucous membranes. Blood/fluid exposure includes things such as accidental needle stick or insect bites.

Triclosan

Broad spectrum antimicrobial agent and pesticide with the IUPAC name of 2,4,4’-trichloro-2’-hydroxydiphenyl ether. It is used as a preservative in other chemicals and is coated on surfaces to inhibit bacterial growth and the accumulation of mildew. Triclosan is used in several consumer products such as hand sanitizer and toothpaste. The FDA is reviewing the safety of this molecule as a topical and oral ingredient though it is not known to be hazardous to humans currently.

Tuberculocidal activity

The capacity of a disinfectant to kill Mycobacterium tuberculosis. Mycobactericidal efficacy testing of disinfectants is carried out in two stages. Tuberculocidal activity includes efficacy against Mycobacterium tubercuolosis, whereas mycobactericidal activity includes all mycobacteria. For proving tuberculocidal activity, European standards require in vitro tests (quantitative suspension tests; in the European Norms referred to as phase 2/step 1, e.g. according to EN 14348). According to the European Norm, the test organism required for claiming mycobactericidal activity is Mycobacterium terrae.

Tuberculocides

Agents that have the capacity to kill Mycobacterium tuberculosis, the causative agent of tuberculosis. Basic antibacterial agents, antiseptics, and disinfectants may not necessarily have the ability to destroy Mycobacterium tuberculosis, which is why chemicals with specific activity against the mycobacteriuma are labeled accordingly

Tuberculosis

A family of diseases (short TB) caused by the aerobic, nonmotile Mycobacterium tuberculosis—the most common is pulmonary tuberculosis, i. e. tuberculosis of the lungs, but any part of the body may be affected. Symptoms of pulmonary tuberculosis include cough with sputum that may contain blood, chest pain, weakness, weight loss, and fever amongst others. Untreated or improperly treated tuberculosis can be fatal and the disease causes more infection-related deaths worldwide than any other infection. Because of its unique, waxy cell wall it is neither Gram positive or negative and requires acid fast staining in order to be detected. Mycobacterium tuberculosis is passed through infected respiratory droplets and only requires ten bacteria for transmission.

Two-bucket method

A method of surface cleaning in which an initial “dirty” bucket is used for detergent while a second “clean” bucket of water is used for rinsing.

Ultrasonic cleaner

A device that creates oscillations (between 20 to 400 kHz) in a solution to clean delicate objects or objects that have a number of small crevices and pores. The high frequency sound waves create cavitations within the solution to break up and dissolve debris that is adhered to the surfaces of the object being clean. The ultrasonic energy applied agitating energy to every surface of the device. Ultrasonic cleaning is superior to manual cleaning because it cleans all areas but inferior to disinfectants because it does not necessarily sterilize or disinfect the object. Ultrasound can enhance the efficacy of a disinfectant or cleanser suited for the particular object and for use in an ultrasonic cleaner.

Urinary tract infection

Typically an infection of the urethra and/or urinary bladder but may also apply to the ureters and/or kidneys (sometimes distinguished as lower and upper UTIs, respectively). Under normal circumstances the urine is sterile due to the filtration capacity of the kidneys. As such, most UTIs are the result of microorganisms introduced through the urethra or external source.

VAH

An acronym which stands for Verbund für Angewandte Hygiene e. V. (German Association for Applied Hygiene). German organization that collaborates with DGHM and other European bodies to establish and ensure standards of antimicrobial disinfection. The VAH Disinfectant Committee examines effectiveness of various sterilants, disinfectants, and other hygiene products.

VAH list

All disinfection procedures and agents that are deemed effective through testing efforts of various German associations and societies. While widely used, disinfection values provided on the list are simply recommendations and not binding regulations.

VISA

Vancomycin-intermediate-resistant Staphylococcus aureus. Strains of S. aureus that are resistant to beta-lactam antibiotics, but also possess intermediate resistance to vancomycin and other glycopeptide antibiotics. Sometimes used intergchangeably with GISA or glycopeptide-intermediate-resistant Staphylococcus aureus.

VRE

Vancomycin-resistant enterococcus. Enterococcal strains that are resistant to vancomycin and other glycopeptide antibiotics. May cause urinary tract infections, bacteremia, bacterial endocarditis, diverticulitis, or meningitis that are difficult to treat.

VRSA

Vancomycin-resistant Staphylococcus aureus. S. aureus strains that are resistant to all beta-lactam antibiotics and exhibit high-level resistance to vancomycin and glycopeptide antibiotics. VRSA infections are still rare but the incidence is expected to increase.

Vaccination

The administration of a prepared antigen whether from living, attenuated, microbes or dead or/ inactivated pathogens, respectively, meant to stimulate a selective immune response against the antigen and confer lasting immunity against the pathogen. The term vaccination was originally reserved to inoculation with a live virus (e.g. vaccinia virus); however live, active virus administration is not usually performed and the name persists on a broader scale. Used interchangeably with immunization.

Vaccinia virus

Enveloped, double-stranded DNA virus that was inoculated into individuals to confer immunity to smallpox and is largely responsible for eradicating that disease. Vaccination with vaccinia virus is performed with a probing motion of a bifurcated needle causing local replication of the virus, a Jennerian pustule, and a characteristic scar after healing. While the vaccinia virus is safe for humans, it may cause organ damage and central nervous system disease in immunocompromised individuals.

Vancomycin-resistant enterococci (VRE)

Enterococci that have acquired a stable and/or inducible genetic change that renders treatment with vancomycin and related antibiotics ineffective. While enterococci colonize various areas on the body and in the gut, they can cause infection when they accumulate in areas such as the urinary tract or normally sterile regions of the body. Enterococcus infection is more common in the immunocompromised and VRE infection is more common in hospitals and in people that have received vancomycin or related antibiotics previously.

Vegetative bacteria

Metabolically active bacteria that are capable of growth. Vegetative bacteria are distinguished from spores, which do not grow or have an active metabolism.

Virucidal

An agent or disinfectant that has the capacity to inactivate enveloped and non-enveloped viruses.

Virucidal activity

The capacitiy of a disinfectant to inactivate viruses. For proving virucidal efficacy of disinfectants, European standards require in vitro tests (quantitative suspension tests; in the European Norms referred to as phase 2/step 1 e.g. EN 14476. The two test viruses required for claiming virucidal activity according to EN 14476 are poliovirus (type 1) and adenovirus (type 5). In Germany, the guidelines of the German Association for the Control of Virus Diseases (DVV) and the Robert Koch Institute (RKI), in deviation from EN 14476, demand additional proof of efficacy against polyomavirus (SV40).

Virucides

Chemicals that possess the ability to inactivate viruses. Since viruses are not living organisms, a virucide renders the virus permanently incapable of infecting a cell and reproducing. Virucides inactivate viruses through direct contact and may denature, oxidize, or break apart viral particles in some way.

Virulent

Denotes a high degree of pathogenicity; a pathogen that is particularly capable of causing disease. A virulent microorganism could be one that requires very few individuals to cause an infection (e.g. Mycobacterium tuberculosis requires only 10 individuals). Alternatively, a virulent microorganism could be one that causes severe signs and symptoms including disability and death in a host organism. The term virulent is discussed in terms of a microorganism’s virulence, which can be expressed as the ratio of those with overt signs and symptoms of the infection to the total number of infected individuals.

Virus

Nonliving entity containing either an RNA or DNA genome encased in a protective capsid and, depending on virus type, a lipoprotein/glycoprotein envelope. Viruses are generally too small to been seen by traditional light microscopy and vary in size from 10 nm to several 100 nm in diameter. They replicate by inserting themselves inside a living cell and using the cell’s molecular machinery (e.g. ribosomes) along with their own to synthesize new copies of viral DNA and the proteins required for new viral particles. Viruses are an important cause of human disease both infections and cancers (e.g. human papillomavirus and cervical cancer).

Volatile Organic Compounds (VOC)

Organic chemicals having a substantial tendency to evaporate. They usually have low solubility in water (hydrocarbons) and the gases can be stored in confined spaces. VOCs are commonly found in chemicals, but are also used as cleaning agents (such as dry chemical cleaners) and as disinfectants. Due to the risk to human health and the environment, VOCs are regulated by strict restrictions.

Volatile organic compounds (VOCs)

Organic chemical products with high vapor pressure at room temperature, which have a substantial tendency to evaporation. In general, they have a water-soluble base (hydrocarbons), and gases can accumulate in sealed spaces. VOCs are commonly found in chemical products, but are also used in cleaning products (for example, chemicals to clean them) and disinfectants. Due to research for human health and the environment, VOCs are highly regulated and, in some cases, restricted.

Volatile organic compounds (VOCs)

Organic chemicals with high vapor pressure at room temperature, having a substantial tendency to evaporate. They generally have a low solubility in water (hydrocarbons) and gases can accumulate in enclosed spaces. VOCs are commonly found in chemical products but are also used in cleaners (e.g. such as dry-cleaning chemicals) and disinfectants. Because of the risk to human health and the environment, VOCs are highly regulated and in some cases restricted.

WHO

Acronym for World Health Organization. Main health authority of the United Nations. Provides international guidelines for health care, establishes global healthcare standards, and supports national health programmes and initiatives.

Washer-disinfector

A device that cleans (removes soil, organic residue, and debris) and disinfects with heat or steam. Washer-disinfectors are meant to clean soiled objects and decrease bioburden however this device does not replace sterilization procedures. Therefore it is appropriate for cleaning and disinfecting most non-critical medical devices but often used for supplies such as glassware and non-sterile instruments. Washer-disinfectors are only suitable use on heat- and corrosion-resistant objects.

West Nile virus

Flavivirus that is carried by various species of birds and transmitted to humans through direct contact with infected birds or, much more commonly, through the bite of a mosquito that previously bit an infected bird. Most West Nile virus infections are asymptomatic however the virus may cause a mild illness called West Nile Fever or a serious illness known as West Nile encephalitis. West Nile encephalitis may cause delirium, confusion, tremors, headache, fever, and flaccid paralysis.

Wipe disinfection

A method of applying chemical disinfectants to a surface using a piece of fabric or fiber to spread the disinfectant liquid over the area. The fabric can be soaked or saturated with the disinfectant liquid or the chemical can be sprayed and then wiped clean (spray-cloth disinfection). This type of disinfection is superior to spray disinfection because it spreads the liquid over the entire surface while it is inferior to spray disinfection when dealing with small areas that the cloth cannot reach. Since the spray produces aerosol particles, its use should be limited.

Wipe disinfection

A method of applying chemical disinfectant to a surface using a piece of fabric or fiber and spreading the liquid disinfectant over the surface. The fabric can be impregnated or saturated with liquid disinfectant or the disinfectant can be sprayed and subsequently wiped with the fabric (spray-wipe-disinfection). Wipe disinfection is superior to spray disinfection alone because it can spread the liquid across an entire surface while at the same time being inferior to spray for small areas that the towel cannot reach. Since spraying produces aerosols, however, the use of sprays should be limited.

Yeasticidal activity

The capacity of a disinfectant to kill yeasts. Fungicidal efficacy testing of disinfectants is carried out in two stages. Yeasticidal activity includes efficacy against yeast-like fungi such as Candica albicans, whereas fungicidal activity includes efficacy against all fungi and their spores. For proving yeasticidal activity of disinfectants, European standards require in vitro tests (quantitative suspension tests; in the European Norms referred to as phase 2/step 1, e.g. according to EN 13624). According to the European Norm, the test organism required for claiming yeasticidal activity is the non-spore forming Candida albicans, a clinically important yeast.

Yeasts

Eukaryotic fungi that reproduce by fission or budding. Candida species are clinically important yeasts. Some fungi can alternate between yeast and hyphal phases.

Yellow fever

Disease caused by a single-stranded, enveloped RNA virus of the Flavivirus family called the yellow fever virus. Yellow fever is acquired from a bite by a specific genus of mosquitoes called Aedes if they carry virus particles in their saliva. Yellow fever gets its name from the jaundice that follows destruction of red blood cells and viral hepatitis. Also causes fever, headache, bleeding disorders (yellow fever is a hemorrhagic fever), and profound weakness. While an effective vaccine exists, it is inconsistently applied in endemic areas, which leads to new cases.

Zoning

An infection control procedure in which areas are designated within the reprocessing area as either clean or dirty. This prevents contaminated objects from being placed in a clean area (i.e. cross-contamination). Zoning is similar to the establishment of a sterile field in surgery except with lower levels of disinfection/sterility.