VICNISS - Glossary for Education Modules

Education Module Glossary

Area	Definition
Airborne Precautions	In addition to Standard Precautions, use Airborne Precautions, or the equivalent, for patients known or suspected to be infected with microorganisms transmitted by airborne droplet nuclei (small-particle residue [5 µm or smaller in size] of evaporated droplets containing microorganisms that remain suspended in the air and that can be dispersed widely by air currents within a room or over a long distance). A. Patient Placement Place the patient in a private room that has 1) monitored negative air pressure in relation to the surrounding areas, 2) 6 to 12 air changes per hour, and 3) appropriate discharge of air outdoors or monitored high-efficiency filtration of room air before the air is circulated to other areas in the hospital. Keep the room door closed and the patient in the room. When a private room is not available, place the patient in a room with a patient who has active infection with the same microorganism, unless otherwise recommended, but with no other infection. When a private room is not available and cohorting is not desirable, consultation with infection control professionals is advised before patient placement. B. Respiratory Protection Wear respiratory protection (N95 respirator) when entering the room of a patient with known or suspected infectious pulmonary tuberculosis. Susceptible persons should not enter the room of patients known or suspected to have measles (rubeola) or varicella (chickenpox) if other immune caregivers are available. If susceptible persons must enter the room of a patient known or suspected to have measles (rubeola) or varicella, they should wear respiratory protection (N95 respirator). Persons immune to measles (rubeola) or varicella need not wear respiratory protection. C. Patient Transport Limit the movement and transport of the patient from the room to essential purposes only. If transport or movement is necessary, minimise patient dispersal of droplet nuclei by placing a surgical mask on the patient, if possible. D. Additional Precautions for Preventing Transmission of Tuberculosis Consult CDC "Guidelines for Preventing the Transmission of Tuberculosis in Health-Care Facilities" for additional prevention strategies.

Antibiotic Resistance	A property of bacteria that confers the capacity to grow in the presence of antibiotic levels that would normally suppress growth or kill susceptible bacteria.

Antibiotics	A subset of antimicrobial agents that include antibacterial agents.

Antimicrobial	A chemical agent that, on application to living tissue or by systemic administration, will selectively kill or prevent growth of susceptible organisms. This definition includes antibacterials, antiprotozoals, antifungals, antiseptics and disinfectants.

Antisepsis	The prevention of infection by topical application of bacteriostatic agents to tissues.

Antiseptic	A substance that is recommended by its manufacturer for dermal application to kill microorganisms or to prevent the growth of microorganisms to a level that may cause clinical infection, and that is not represented to be suitable for internal use.

Asepsis	The prevention of microbial contamination of living tissues or sterile materials by removal, exclusion or destruction of microorganisms.

Aseptic technique	Is one in which the instruments, the drapes and the gloved hands of the surgical team are sterile.

Cleaning	The physical removal of foreign material, for example, dust, soil, organic material such as blood, secretions, excretions and microorganisms. Cleaning physically removes rather than inactivates microorganisms. Cleaning is accomplished with water, detergents and mechanical action. Cleaning must precede disinfection and sterilisation.

Cohort Management	Management of a group of individuals infected with the same infectious agent in the same place (eg. MRSA infected patients managed in one ward).

Colonisation	The presence, growth and multiplication of an organism without observable clinical symptoms or immune reaction in a patient.

Contact Precautions	In addition to Standard Precautions, use Contact Precautions, or the equivalent, for specified patients known or suspected to be infected or colonised with epidemiologically important microorganisms that can be transmitted by direct contact with the patient (hand or skin-to-skin contact that occurs when performing patient-care activities that require touching the patient's dry skin) or indirect contact (touching) with environmental surfaces or patient-care items in the patient's environment. A. Patient Placement Place the patient in a private room. When a private room is not available, place the patient in a room with a patient(s) who has active infection with the same microorganism but with no other infection (cohorting). When a private room is not available and cohorting is not achievable, consider the epidemiology of the microorganism and the patient population when determining patient placement. Consultation with infection control professionals is advised before patient placement. B. Gloves and Handwashing In addition to wearing gloves as outlined under Standard Precautions, wear gloves (clean, nonsterile gloves are adequate) when entering the room. During the course of providing care for a patient, change gloves after having contact with infective material that may contain high concentrations of microorganisms (fecal material and wound drainage). Remove gloves before leaving the patient's room and wash hands immediately with an antimicrobial agent or a waterless antiseptic agent. After glove removal and handwashing, ensure that hands do not touch potentially contaminated environmental surfaces or items in the patient's room to avoid transfer of microorganisms to other patients or environments. C. Gown In addition to wearing a gown as outlined under Standard Precautions, wear a gown (a clean, nonsterile gown is adequate) when entering the room if you anticipate that your clothing will have substantial contact with the patient, environmental surfaces, or items in the patient's room, or if the patient is incontinent or has diarrhea, an ileostomy, a colostomy, or wound drainage not contained by a dressing. Remove the gown before leaving the patient's environment. After gown removal, ensure that clothing does not contact potentially contaminated environmental surfaces to avoid transfer of microorganisms to other patients or environments. D. Patient Transport Limit the movement and transport of the patient from the room to essential purposes only. If the patient is transported out of the room, ensure that precautions are maintained to minimise the risk of transmission of microorganisms to other patients and contamination of environmental surfaces or equipment. E. Patient-Care Equipment When possible, dedicate the use of noncritical patient-care equipment to a single patient (or cohort of patients infected or colonised with the pathogen requiring precautions) to avoid sharing between patients. If use of common equipment or items is unavoidable, then adequately clean and disinfect them before use for another patient. F. Additional Precautions for Preventing the Spread of Vancomycin Resistance Consult the HICPAC report on preventing the spread of vancomycin resistance for additional prevention strategies.

Contamination	The introduction of microorganisms or foreign matter (or both) to sterile or nonsterile materials or living tissue.

Category Specific Rate	A category specific rate is a rate calculated for a subpopulation so that comparisons are possible.

Crude Rate	A crude rate is an overall rate for an entire population. This rate may be confounded by differences found in groupings or subpopulations within the overall population. For example, a hospital wide infection rate is a crude rate. Hospital A and Hospital B cannot interpret the differences between their overall rates because the crude rates do not give enough information about the risk factors and types of patients found in each facility.

Decontamination	The removal of microorganisms or foreign matter (or both) from contaminated materials or living tissue.

Denominator	The lower portion of a fraction used to calculate a rate or ratio. For calculation of infection rates, denominators should closely represent the population at risk. If time is an important component of that exposure to risk, simple measures such as numbers of discharges or admissions is not valid.

Direct Contact Transmission	A mode of transmission between an infected host and a susceptible host.

Disinfectant	A substance that is recommended by its manufacturer for application to an inanimate object to kill a range of microorganisms; and that is not represented by the manufacturer to be suitable for internal use.

Disinfection	The inactivation of nonsporing microorganisms using either thermal (heat alone, or heat and water) or chemical means.

Droplet Precautions	In addition to Standard Precautions, use Droplet Precautions, or the equivalent, for a patient known or suspected to be infected with microorganisms transmitted by droplets (large-particle droplets [larger than 5 µm in size] that can be generated by the patient during coughing, sneezing, talking, or the performance of procedures). A. Patient Placement Place the patient in a private room. When a private room is not available, place the patient in a room with a patient(s) who has active infection with the same microorganism but with no other infection (cohorting). When a private room is not available and cohorting is not achievable, maintain spatial separation of at least 3 ft between the infected patient and other patients and visitors. Special air handling and ventilation are not necessary, and the door may remain open. B. Mask In addition to wearing a mask as outlined under Standard Precautions, wear a mask when working within 3 ft of the patient. (Logistically, some hospitals may want to implement the wearing of a mask to enter the room.) C. Patient Transport Limit the movement and transport of the patient from the room to essential purposes only. If transport or movement is necessary, minimize patient dispersal of droplets by masking the patient, if possible.

Fomites	Articles that convey infection to others because they have been contaminated by pathogenic organisms. eg. medical equipment.

Gram Negative Microorganism (Gm-ve)	These organisms survive best in wet or damp areas such as the gut and perineum, sinks and showers.

Gram Positive Microorganism (Gm+ve)	These organisms survive well in dry areas, such as the skin, hands, dust, floors, and sheets.

Immunocompromised Patients	People whose immune system is not functioning normally because of an immunodeficiency disorder or other disease, or as the result of the administration of immunosuppressive drugs or radiation.

Incidence	Incidence measures the number of new cases of disease within a population over a given period of time. The numerator is the number of cases of the disease that have developed in a given time period; the denominator is the initial population at risk to develop that disease.

Incidence Rate (Incidence Density)	Incidence density, uses a denominator of person-time units, which accounts for the variation in the periods of follow-up for each subject. This involves calculating a rate in which the numerator is not included in the denominator. For example, incidence density is used in the calculation of ventilator associated pneumonia rates. In this instance the numerator is the number of pneumonia cases that occurred in ventilator patients for a specified time period, and the denominator is the number of ventilator days, with ventilator days representing time units of exposure for these patients.

Incubation Period	The time that elapses between infection and the appearance of symptoms of a disease.

Indirect Contact Transmission	A mode of transmission of infection involving fomites or vectors.

Infection	Is the invasion of bacteria into tissues with replication of the organism. Infection usually produces clinical signs such as fever, purulence (pus) and inflammation (warmth, redness and swelling).

Intermediate Resistance	This refers to a micro-organism which has partial but not complete resistance to an antibiotic.

Negative Pressure	Used to denote airflow which is negative in relation to surrounding air pressure, that is, air flows away from the surrounding area. Usually created by mechanical airflow devices (eg exhaust fans).

Nosocomial Infection	An infection is classified as nosocomial if it was not present or incubating at the time the patient was admitted to hospital.

Numerator	The numerator is the upper portion of a fraction used to calculate a rate or ratio. The numerator represents each event (eg. infection) that occurs during the defined period of interest.

Outlier	An observation differing widely from the rest of the data. For example, an infection rate that is much higher or lower than other rates in the data set.

Pathogen	Organism capable of producing disease.

Pathogenicity	The property of an organism that determines the extent to which overt disease is produced in an infected population, or the power of an organism to produce disease. Pathogenicity of infectious agents is measured by the ratio of the number of persons developing clinical illness to the number exposed to infection. See also Virulence.

Period Prevalence	Period prevalence is a combination of prevalence and incidence. The numerator is the number of cases of disease existing at the beginning of the study, in addition to all new cases that develop during the study period. The denominator is the entire population from which the numerator was derived.

Prevalence	Prevalence measures the proportion of cases of existing disease within a defined population at a given point in time. It is obtained by dividing the number of cases of existing disease by the total population.

Proportion	Proportion is a type of ratio, often expressed as a percentage, in which the numerator must be included in the denominator. For example, the proportion of cases of cholecystectomy in which a surgical site infection developed. The numerator would be the number of infections, the denominator would be the total number of cholecystectomies that were conducted during the study period.

Rate	A rate is a ratio with a particular relationship between the numerator and denominator, in which time measurement is included in the denominator. (Note: the term rate is often inexactly applied to measures that may be true rates, ratios or proportions).

Ratio	Ratio is a general term; it is obtained by dividing one number by another. There is no implication that the numerator and denominator are related. For example, the ratio of men to women in a population.

Reservoir	Any person, animal, arthropod, plant, soil, or substance or a combination of these, in which an infectious agent normally lives and multiplies, on which it depends primarily for survival, and where it reproduces itself in such a manner that it can be transmitted to a susceptible host. The natural habitat of the infectious agent.

Respiratory Isolation Room	A single room with an ensuite and engineered such that the interior of the room can be made to be at a negative pressure with respect to the corridor, and that air from the room is not recirculated into other areas within the facility.

Sensitivity and Specificity	An ideal surveillance detects and counts all “true” cases of infection and excludes false positives, ie. cases that are not infections. Sensitivity is a measure of how well the surveillance system is detecting infections, and can be defined as the proportion of those with a nosocomial infection in the targeted population that is identified by the case finding methodology. Specificity is a measure of how good the system is at excluding potential cases who do not have an infection, and can be defined as the proportion of those without a nosocomial infection in the targeted population as correctly identified by the case finding methodology. A balance has to be struck between sensitivity and specificity; increasing one almost always reduces the other. In practical terms it is usually necessary to strike a balance between finding all true cases and the amount of effort necessary to track down cases that may turn out to be false positives.

Source	The person, animal, object or substance from which an infectious agent passes to a host.

Standard Precautions	Use Standard Precautions, or the equivalent, for the care of all patients. A. Handwashing Wash hands after touching blood, body fluids, secretions, excretions, and contaminated items, whether or not gloves are worn. Wash hands immediately after gloves are removed, between patient contacts, and when otherwise indicated to avoid transfer of microorganisms to other patients or environments. It may be necessary to wash hands between tasks and procedures on the same patient to prevent cross-contamination of different body sites. Use a plain (nonantimicrobial) soap for routine handwashing. Use an antimicrobial agent or a waterless antiseptic agent for specific circumstances (eg. control of outbreaks or hyperendemic infections), as defined by the infection control program. (See Contact Precautions for additional recommendations on using antimicrobial and antiseptic agents.) B. Gloves Wear gloves (clean, nonsterile gloves are adequate) when touching blood, body fluids, secretions, excretions, and contaminated items. Put on clean gloves just before touching mucous membranes and nonintact skin. Change gloves between tasks and procedures on the same patient after contact with material that may contain a high concentration of microorganisms. Remove gloves promptly after use, before touching noncontaminated items and environmental surfaces, and before going to another patient, and wash hands immediately to avoid transfer of microorganisms to other patients or environments. C. Mask, Eye Protection, Face Shield Wear a mask and eye protection or a face shield to protect mucous membranes of the eyes, nose, and mouth during procedures and patient-care activities that are likely to generate splashes or sprays of blood, body fluids, secretions, and excretions. D. Gown Wear a gown (a clean, nonsterile gown is adequate) to protect skin and to prevent soiling of clothing during procedures and patient-care activities that are likely to generate splashes or sprays of blood, body fluids, secretions, or excretions. Select a gown that is appropriate for the activity and amount of fluid likely to be encountered. Remove a soiled gown as promptly as possible, and wash hands to avoid transfer of microorganisms to other patients or environments. E. Patient-Care Equipment Handle used patient-care equipment soiled with blood, body fluids, secretions, and excretions in a manner that prevents skin and mucous membrane exposures, contamination of clothing, and transfer of microorganisms to other patients and environments. Ensure that reusable equipment is not used for the care of another patient until it has been cleaned and reprocessed appropriately. Ensure that single-use items are discarded properly. F. Environmental Control Ensure that the hospital has adequate procedures for the routine care, cleaning, and disinfection of environmental surfaces, beds, bedrails, bedside equipment, and other frequently touched surfaces, and ensure that these procedures are being followed. G. Linen Handle, transport, and process used linen soiled with blood, body fluids, secretions, and excretions in a manner that prevents skin and mucous membrane exposures and contamination of clothing, and that avoids transfer of microorganisms to other patients and environments. H. Occupational Health and Bloodborne Pathogens Take care to prevent injuries when using needles, scalpels, and other sharp instruments or devices; when handling sharp instruments after procedures; when cleaning used instruments; and when disposing of used needles. Never recap used needles, or otherwise manipulate them using both hands, or use any other technique that involves directing the point of a needle toward any part of the body; rather, use either a one-handed "scoop" technique or a mechanical device designed for holding the needle sheath. Do not remove used needles from disposable syringes by hand, and do not bend, break, or otherwise manipulate used needles by hand. Place used disposable syringes and needles, scalpel blades, and other sharp items in appropriate puncture-resistant containers, which are located as close as practical to the area in which the items were used, and place reusable syringes and needles in a puncture-resistant container for transport to the reprocessing area. Use mouthpieces, resuscitation bags, or other ventilation devices as an alternative to mouth-to-mouth resuscitation methods in areas where the need for resuscitation is predictable. I. Patient Placement Place a patient who contaminates the environment or who does not (or cannot be expected to) assist in maintaining appropriate hygiene or environmental control in a private room. If a private room is not available, consult with infection control professionals regarding patient placement or other alternatives.

Sterilisation	Complete destruction of all microorganisms, including spores.

Vector	An insect or any living carrier that transports an infectious agent from an infected individual or its wastes to a susceptible individual or its food or immediate surroundings.

Virulence	The degree of pathogenicity; the disease evoking power of a microorganism in a given host. Numerically expressed as the ratio of the number of cases of overt infection in the total number infected.

Window Period	The period immediately after a person is infected with an agent, during which the infection is not detectable by laboratory tests, although the person may be infectious.

75th Percentile	The number in a sample of measurements which is larger than 75% of the measurements in the sample and smaller than 25% of the measurements in the sample.