Infection Control Flashcards
What are the links in chain of infection?
Infectious Agent Reservoir Portal of exit Mode of transmission Portal of entry Susceptible host
What are possible infectious agents?
pathogens
bacteria, viruses, fungi, protozoa, and
prions
normal flora
may become pathogenic when entered into the
body
What is a reservoir?
a source of infection where infection can survive and multiply
Name some types of reservoirs.
Living = Humans, insects, animals
Nonliving = Soil, water, food, and environmental surfaces
What is a carrier?
An individual who has no symptoms despite carrying a disease which they can pass to others.
What are some portals of exit?
- body fluids (blood, saliva, breast milk, urine, feces, vomitus, semen or other secretions)
- Cuts
- Bites
- Abrasions
- Nosocomial sites
puncture sites, drainage tubes, feeding tubes,
IV lines, colostomy lines, catheters etc.
What are the modes of transmission?
Direct contact Indirect contact with a fomite (contaminated object) droplet transmission airborne transmission a vector
What is a vector?
an organism that carries a pathogen to a susceptible host
What are examples of a portal of entry?
normal body openings
eyes, nostrils, mouth, urethra, vagina,
anus
abnormal body openings
cuts and scrapes, burns, bites by vectors
What three factors determine whether a person develops an infection?
- The virulence of the organism
- The number of organisms transmitted
- The ability of the host’s defenses to prevent infection
An infection that is limited to a specific region is called a _______.
Local infection
An infection that invades the blood or lymph and travels throughout the body is called a ________
Systemic infection
A primary infection is the
first infection that occurs in a patient
A secondary infection is the
one or more infections that occur in a patient who is already fighting an infection
What are the common portals of exit?
Respiratory Gastrointestinal Genitourinary tracts Breaks in skin Blood and tissue
An exogenous nosocomial infection is
where the pathogen is acquired from the healthcare environment
An endogenous nosocomial infection is
where the pathogen arises from the patients normal flora and some form of treatment
What is an acute infection
a rapid onset but short lasting infection
What is a chronic infection
infections that develop slowly and last for weeks, months or years
What is a latent infection
an infection that causes no symptoms for long periods of time (HPV, HIV)
What are the stages of infection?
- Inflammatory Phase
- Proliferation Phase
- Remodelling Phase
Describe the inflammatory stage
The stage between successful invasion and the appearance of symptomsMay be infectious
Describe the proliferation stage
marked by the appearance of signs and symptoms characteristic of the diseaseMay result in death
Describe the remodelling stage
characterized by tissue repair and a return to health as the number of microorganisms near zero.
may require anywhere from one day to a year or more
What are the laboratory data indicating infection?
- Elevated WBC count (>10,000 mm3)
- Increases in specific types of WBCs
- Elevated erythrocyte sedimentation rate
- Presence of pathogen in urine, blood, sputum or draining cultures
What are the factors affecting host suceptibility?
- Intact skin and mucous membranes
- Normal pH levels
- White blood cells
- Age, sex, race, hereditary factors
- Immunization, natural or acquired
- Fatigue, climate, nutritional and general health status
- Stress
- Use of invasive or indwelling medical devices
What are primary defenses?
- Skin
- The respiratory tree (spec. mucous membranes that trap pathogens)
- Eyes
- The mouth
- The GI tract
- The Genitourinary tract
What are the secondary defenses?
Phagocytosis
The complement cascade
Inflammation
Fever
What is the complement cascade?
a process by which a set of blood proteins called complement triggers the release of chemicals that attach the cell membranes of pathogens and cause them to erupt.
What are the tertiary defenses?
Humoral immunity
Cell-mediated immunity
What is the function of Basophils?
Release histamine and heparin granules as part of the inflammatory response
What is the function of Eosinophils?
Destroy helminths
mediate allergic reactions
have limited role in phagocytosis