1 Basic Concepts Flashcards
What is the definition of these terms:
Airborne transmission
Transmission of infectious agents by either airborne nuclei
or particles of <5 mm in size.
What is the definition of these terms:
antiseptic
asepsis
Antiseptic - a chemical agent which, when applied to living tissue , will destroy or inhibit the reproduction of microorganisms.
Asepsis - the prevention of microbial contamination of living tissues or sterile materials by removal, exclusion, or destruction of microorganisms.
What is the definition of these terms:
cleaning
The physical removal of foreign material, e.g. 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.
What is the definition of these terms:
Community acquired infection
This is an infection which was present, or
incubating, at the time the patient was admitted to hospital. It is possible that the
infection may only become apparent after the patient has been admitted. As a
general rule, an infection which appears within 72 hours of admission may be
considered to have been ‘community-acquired’, though more exact criteria will
take into account the nature of the infecting organism and the incubation period
of the disease.
What is the definition of these terms:
decontamination
disinfection
Decontamination - a process which removes or destroys contamination and thereby prevents microorganisms or other contaminants from reaching a susceptible site in sufficient quantities to initiate infection or any other harmful response.
Disinfection - the inactivation of non-sporing microorganisms using either thermal (heat alone, or heat and water) or chemical means.
What is the definition of these terms:
endemic
Endemic - The usual level or presence of an agent or disease in a defined population
during a given period.
What is the definition of these terms:
Exposure prone procedure
Exposure prone procedure - A subset of ‘invasive procedures’ characterized by the potential for direct contact between the skin (usually finger or thumb) of the health care worker and sharp surgical instruments, needles, or sharp tissues (spicules of bone or teeth) in body cavities or in poorly visualized or confined body sites (including the mouth). In the broader sense, an exposure-prone procedure is considered to be any situation where there is a potentially high risk of transmission of blood-borne disease from the health care worker to patient during medical or dental procedures (UK Department of Health).
What is the definition of these terms:
Healthcare associated infection
Hospital acquired infection
Health care-associated infections The term health care-associated infections refers to infections associated with health care delivery in any setting (e.g. hospitals, long-term care facilities, ambulatory settings, home care). This term reflects the uncertainty in always being able to determine where the pathogen is acquired. Patients may be colonized with, or exposed to, potential pathogens outside of the health care setting before receiving health care, or may develop infections caused by those pathogens when exposed to the conditions associated with delivery of health care. Additionally, patients frequently move among the various settings within a health care system.
Hospital-acquired infection (nosocomial infection) Infection acquired during hospitalization; not present or incubating at the time of admission to hospital. In general, infections that occur more than 72 hours after admission and within 10 days after hospital discharge are defined as nosocomial or hospital acquired . The time frame is modified for infections that have incubation periods less than 72 hours (e.g. gastroenteritis caused by Norwalk virus) or longer than 10 days (e.g. hepatitis A). Surgical site infections are considered nosocomial if the infection occurs within 30 days after the operative procedure or within 1 year if a prosthetic device or foreign material is implanted. Also see health care-associated infections.
What is the definition of these terms:
medical device
Medical device According to the UK Medical Device Agency a medical device is an instrument, apparatus, appliance, material, or other article, whether used alone or in combination, intended by the manufacturer to be used on human beings for the purpose of: diagnosis, prevention, monitoring, treatment, or alleviation of disease, diagnosis, monitoring, treatment, alleviation of or compensation for an injury or handicap, investigation, replacement, or modification of the anatomy or physiological process and control of conception.
What is the definition of these terms:
standard precautions
Standard precautions Work practices required to achieve a basic level of infection control. Standard precautions are recommended for the treatment and care of all patients. Standard precautions include good hygiene practices, particularly
washing and drying hands before and after patient contact, use of personal protective equipment, careful handling and disposal of sharps and clinical waste, and the use of aseptic techniques.
Pathogenesis of infection
What 3 factors are important when considering the likelihood of establishing a bacterial infection?
Number of microbes - infective dose
Virulence - capacity for microbes to cause disease
Immune status of patient - increasing age, diabetes, chemotherapy. Also immunity through vaccination or previous disease eg VZV
Patient exposed to infectious agent
What are possible outcomes following this?
No infection - immunity from previous infection/ immunisation
Clinical/ sub-clinical infection
Colonisation/ carriage - e.g MRSA, VRE, ESBL do not always cause disease
What is difference between exogenous and endogenous acquired infection
exogenous - from external environment e.g hospital equipment
endogenous - from patient’s own microflora - particularly neutropaenic transplant patients
Chain of infection
What are the 6 vital links of transmission
Causative agent
Reservoir of infection - e,g person, animal, water, food, equipment, environment
Portal of exit e.g respiratory/ GI
Mode of transmission - e.g cough, diarrhoea, direct contact
Portal of entry - e.g inhalation of droplets
Susceptible host - e.g immunocompromised or unvaccinated patient
Carriers can be classified into 4 categories, what are they?
Incubating carrier - acquired infection, and incubating. Without overt symptoms
Convalescent carrier - had infection, and recovering. Continues to shed pathogen after symptom disappear e.g Salmonella
Intermittent carrier - occassionally shed pathogenic organism
Chronic carrier - always has infection in body e.g HIV
