Glossary infection

Adhesins Microbial factors that enable bacteria to adhere to cells.
Aerosol-generating procedure A procedure that can create an aerosol of the patient’s
secretions, e.g. oro/nasopharyngeal suctioning, positive pressure ventilation, cardiopulmonary
resuscitation, chest physiotherapy, bronchoscopy, creating droplets small and
light enough to become airborne, increasing the possibility for transmission of infection
to occur.
Alcohol handrub An alcohol-based liquid, foam or gel for use on the hands to disinfect
the skin.
Alert organisms Organisms that can cause outbreaks of infection that are difficult to
treat due to antibiotic resistance.
Antibiogram A report that shows which of the antibiotics that are routinely tested will
inhibit the growth of or kill the infectious agents they are tested on. Used to help make
decisions about which antibiotics to use.
Asepsis The freedom from contamination by pathogenic organisms.
Aseptic technique A procedure or practice used to avoid introducing bacteria to a
susceptible site, e.g. wound care, intravenous infusion management, insertion of invasive
devices.
Augmented care unit Clinical areas with a high level of intervention, such as intensive
therapy, high dependency and neonatal care units.
Auto-infection When microorganisms already present on the body cause an infection.
Bacteraemia The presence of an infectious agent in the blood.
Bactericidal Kills bacteria.
Bacteriostatic Inhibits bacterial growth but does not kill bacteria.
Bay A hospital room where more than one inpatient can stay that may have between two
and six beds.
Bloodborne virus Viruses that are carried in the bloodstream, e.g. HIV, hepatitis B,
hepatitis C.
Cadaver Dead body.
Case A person with clinical signs of infection (see below).
CE mark A visible sign that the manufacturer of the product is declaring conformity with
all of the Directives relating to that product.
Cleaning The complete removal of soil from a medical device employing manual or automated
processes.
Clinical signs of infection Typically, these are pyrexia, diarrhoea, an unexplained rash,
localised redness, heat, pain, swelling and loss of function at the site. Other signs include
increased exudate or slowness to heal or show any signs of improvement in a wound. If
the patent has a urinary tract infection they may have dysuria, confusion, frequency of
micturition. It is essential to look for clinical signs of infection when managing patients
and not to focus solely on microbiological reports.

Co-infection When a person is infected with more than one infective agent at the same
time.
Cohort A group.
Cohorting Nursing patients grouped together because they either have the same infection
or have been exposed to the same type of infection.
Coliforms Gram-negative bacilli of the Enterobacteriaceae spp. found in the intestines of
humans and animals. Many coliforms are human pathogens.
Colonisation The presence of an infectious agent in or on the body without causing
injury or infection. It may persist indefinitely.
Commensal A microorganism that lives on the body and benefits from being there whilst
causing no harm to the host.
Contact A person exposed to the risk of infection from being in close proximity to an
infected person.
Contact bay An area where contacts of a person known to be infected with or carrying
an infection are nursed together to minimise the risk of spreading the infection to others
who have not been exposed.
Contact tracing Process of identifying contacts of an infected person.
Contamination
1. Transient presence of microorganisms in or on the body without causing injury or
infection.
2. Not clean – soiled.
3. A contaminated sample has extraneous matter in it, e.g. skin flora in a blood culture
sample.
COSHH Control of substances hazardous to health.
Cross-infection Infection of a person with microorganisms from another person.
Cumulative effect Increasing antimicrobial effect associated with repeated application
of a given antiseptic.
Cytostatic Inhibits cell growth and division.
Cytotoxic Toxic to cells.
Disinfection The removal of most viable organisms using heat or chemicals (does not
necessarily inactivate some viruses and bacterial spores).
Ectoparasite A parasite that lives on the surface of the host.
EIA Enzyme immunoassay – a test to detect antigens and antibodies. Often referred to as
enzyme linked immunosorbent assays (ELISA).
Endemic A persistent low or moderate level of disease in a population.
Endogenous infection An infection where the source is thought to be the patient, e.g.
MRSA in a wound in a patient known to carry MRSA on their skin.
Endoparasite A parasite that lives inside the host.
Epidemic An outbreak of an infectious disease that spreads rapidly and widely.
Exogenous infection An infection where the source is thought to be external to the
patient, i.e. transmitted from another source.
Exposure-prone procedure (EPP) A procedure where there is a risk that injury to the
healthcare worker may result in exposure of the patient’s open tissues to the blood of
the healthcare worker, e.g. where the healthcare worker’s gloved hands are exposed to
blades, needles and other sharp items inside the patient’s open body cavity, wound or
confined anatomical space where the hands or fingertips may not be fully visible at
all times.
Fit testing A series of movements carried out in a controlled setting whilst wearing an
FFP3 mask to test how well it fits the wearer
Fomites Inanimate objects that can become contaminated and provide a vehicle for
transmission of infection.
Herd immunity Due to a high vaccine uptake there is reduced opportunity for a microorganism
to be transmitted within a population.
Host The person infected/infested with an organism.
Hyperendemic A persistent high level of disease in a population.
Impedins Factors that impede host defence mechanisms.
Incidence The number of new cases of an infection over a given period of time.
Incubation period The time when a person has been infected by an infectious agent but
does not yet have clinical signs of infection.
Index case The first person to have symptoms in an outbreak of infection.
Infection Injury or invasion of the tissue caused by an infectious agent.
Infectious agent The specific agent(s) causing the disease.
Infectious period The time during which an infection can be passed from one person
to another.
Infective dose The number of microbes necessary to cause infection.
Inoculation injury Sharps injury.
Invasiveness The ability of an infectious agent to enter and spread in the body.
Liquor Amniotic fluid.
Low-use outlet A tap that is not used daily in augmented care areas or every three days
in general areas.
Medical device A product that has a medical use that is not medicine.
Mode of transmission The mechanisms by which infectious agents are spread (direct
contact, indirect, droplet and airborne).
Normal bacterial flora
Site Normal flora
Mouth Alpha-haemolytic streptococci
Neisseria spp.
Anaerobes
Nose, throat and sputum Alpha-haemolytic streptococci
Neisseria spp.
Diphtheroids (Corynebacteria)
Skin Coagulase-negative staphylococci
Non-haemolytic streptococci
Enterococci
Diphtheroids (Corynebacteria) Propionibacteria
Bowel and faeces Enterobacteriaceae (coliforms) Enterococci
Anaerobes
Candida
Vagina Lactobacilli
Alpha-haemolytic streptococci Diphtheroids (Corynebacteria)
Group B streptococcus
Normal flora The community of microorganisms that live on the human body.
Nosocomial Hospital acquired.
Occurrence Where the disease is known to occur and the population groups affected.
Opportunistic pathogen A microorganism that would not normally cause disease
under normal circumstances that is capable of causing disease when host defence mechanisms
are impaired.
Outbreak Two or more cases of the same infection that are linked, e.g. same ward/cared
for by same healthcare worker/members of the same household, etc.
Pandemic A global outbreak of an infectious disease.
Parasite A parasite living in a close relationship with another organism (its host) and
causing it harm.
Pathogen A microorganism capable of causing disease.
Pathogenicity The ability of a microorganism to cause disease.
PCR Polymerase chain reaction – a test used to identify bacteria and viruses, quantify
viral loads (the amount of virus in the bloodstream) and sometimes to test antibiotic
sensitivities.
Period of infectivity/ communicability Time when a person is shedding microorganisms
and is infectious to others.
Personal protective equipment (PPE) Gloves, aprons, gowns, masks and eye protection,
which may be goggles or visors.
Post-exposure prophylaxis Medicinal products given following a sharps/splash injury to
prevent the injured person from developing a bloodborne virus infection.
PPM Parts per million.
Prevalence The total number of people with an infection over a given period of time.
Prophylaxis Treatment given as a preventative measure.
Protective isolation Nursing a person who is vulnerable to infection in a single room to
protect them from transmission of infection.
Pyogenic Pus forming.
Reservoir of infection A permanent source of infection. This can be a person, an insect,
an animal, a plant, a substance or an environment where an infectious agent can survive,
live and multiply before transmission to a susceptible host.
Resident flora Microorganisms residing under the superficial cells of the stratum corneum
and also found on the surface of the skin.
Resistance Mechanisms by which bacteria avoid destruction.
Respiratory hygiene The practice of covering the mouth or nose when coughing or
sneezing (using a tissue) followed by hand washing to prevent the spread of infection.
Screening Taking of samples for microbiological testing to determine carriage of a microorganism
in the absence of clinical signs of infection.
Sepsis Clinical infection.
Septicaemia The presence of an infectious agent in the blood with symptoms of
infection.
Sharps injury Needle prick, cut, scratch or bite injury.
Single use Use item once and discard.
Single patient use Item can be used more than once on same patient.
Source isolation Nursing a person who has an infection in a single room to prevent
transmission to others.
sp. Species (singular).
Splash-generating procedure An activity that creates a risk of splashing of blood or
body fluids.
Splash injury Blood/body fluid splash into the eyes, mouth or on to broken skin.
Sporadic Occasional cases of a disease occurring at irregular intervals.
Spore A tough protective coat that forms around a bacterial cell making it resistant to
drying, heat and chemicals for months or even years.
spp. Species (plural).
Sterilisation The removal of all viable microorganisms, including viruses and bacterial
spores.

Super-infection When a person is infected with an infective agent and subsequently
becomes infected with another infective agent at a later time.
Surveillance Systematic process of observation, analysis and reporting of the incidence
of disease in a population.
Susceptibility Information on populations at risk of or resistant to infection/disease.
Susceptible host A person at risk of infection/ disease.
Toxin A substance released by a bacterial cell that causes ill effects within the body.
Transient flora (transient microbiota) Microorganisms that colonise the superficial layers
of the skin and are more amenable to removal by routine hand washing.
Vector An organism that passes on a means of causing infection without becoming
infected itself, e.g. mosquitoes are vectors in the transmission of malaria, as they carry
the malarial parasites, which they inject into the host when they bite.
Vertical transmission Transmission of infection from mother to child during pregnancy
or childbirth.
Viral load The number of viral particles in the blood used to measure disease progression
or response to treatment.
Virulence Characteristics of bacteria that enable them to cause infection and disease
such as the ability to produce toxins, adhesins and impedins.
Visibly soiled hands. Hands on which dirt or body fluids are readily visible.
Zoonoses Diseases that can be passed from animals to humans.