Module 2 Flashcards
Where do microbial populations establish themselves on the body?
Skin and mucous membranes
What area of the body has the greatest NF population and what is the organism?
The large intestine
E. Coli
What affects NF?
Excess moisture on skin (+)
Antibiotic use
What are the differences between contamination, colonization and infection/disease?
Contamination- bacteria is found where it normally isn’t. No growth.
Colonization- bacteria is found where it normally isn’t and grows. No host affect.
Infection- damage has resulted from bacteria but isn’t noticeable
Disease- damage has resulted from bacteria and is evident
What is a pathogen?
A disease causing organism
What are opportunistic/low grade pathogens?
Bacteria that are nonpathogenic under normal circumstances but can cause disease when defences are lowered or the immune system is compromised.
What’s the difference between endo- and exotoxins?
Endo- produced by G-, released when the cell is lysed, general effect
Exo- produced by G+, released from intact cells, specific effect
What are the three elements required for infection transmission?
- Source
- Means of transmission
- Susceptible host
How can the chain of infection be broken?
Immunizations
Standard precautions and isolation procedures
Sterilization, disinfection, cleaning and waste disposal
What are the categories of reservoirs for infectious microbes?
- Human
- Animal
- Nonliving
What is the principle reservoir of human disease?
The human body
What is a carrier?
A person who is harbouring pathogenic organisms but has no signs of infection
What is normal flora?
Protective organisms that are present and do not cause disease. Outcompete pathogenic bacteria.
What is the difference between a convalescent and chronic carrier?
Convalescent- the person had the disease, systems are gone but the microbes are still present
Chronic- six months after symptoms subside microbes are still present
What are the different types of contact transmission?
- Direct- reservoir to host
- Indirect- reservoir to fomite to host
- Droplet
What is vehicle transmission?
Reservoir is air, food/water, blood. Something else is carrying the organism.
What are the different types of vehicle transmission?
- Food/water
- Droplet nuclei
- Injected solutions
What is vector transmission?
The microorganism is transferred via an insect
What factors influence host susceptibility?
Age, general health, treatments that compromise the immune system (chemo, radiation, antibiotics), surgery, anaesthesia, catheters.
What are portals of entry?
Skin- hair follicles/sweat glands, moist, broken skin
Mucus membranes
Placenta- only some microbes can cross
Parenteral- through a “poke”
What are common signs of infection?
Fever, lymph node swelling, inflammation
What constitutes a fever?
Increase of body temp by 1°C
How is heat generated in a fever?
Vasoconstriction, increased metabolic week, shivering
What happens when fever breaks?
Heat loss via vasodilation and sweating
Why do lymph nodes swell during infection?
The nodes trap microbes and become infected or the lymphocytes in nodes multiply
What are the four signs of inflammation?
Heat, redness, pain, swelling
What is released when a pathogen causes an infection?
Histamine
What is the chain reaction of inflammation?
- Histamine is released
- Blood vessels become more permeable
- Fluid leaks into tissue with antibodies and coagulation factors
- Increased phagocytes
- Purulent exudate
- Leukocytosis
What is a nosocomial infection?
An infection acquired in hospital.
What contributes to nosocomial infections?
Hospital microbes
Compromised patients
The transmission of microbes is facilitated
What are the top three nosocomial infections acquired?
Urinary tract infection
Surgical wound infection
Pneumonia
What are surgical wounds normally infected with?
Staph aureus, most healthcare workers are staph carriers
What are antibiotics?
Substances produced by a microorganism that inhibits the growth or kills another microorganism.
What does antibiotic testing show?
What antibiotics a microorganism is or isn’t sensitive to.
What are super bugs?
Bacteria that are resistant to many antibiotics.
Why do bacteria develop resistance?
Natural resistance
Develop enzymes
Mutation
Conjugation
What are some examples of super bugs?
MRSA
VRE
C. difficle
Why are super bugs a concern?
Fewer antibiotics for treatment
Drug resistant strains may spread to others in a health care facility
What is the concern with VRE and MRSA?
If VRE and MRSA conjugate there will be very few antibiotics to treat them.
Why is silver imbedded in bandages?
It has antimicrobial properties.
What are phages?
Viruses that infect specific bacterial cells and destroy them.
What parts of infection prevention and control are there?
AHS oversees programs
Healthcare facilities monitor nosocomial infections and implement policies
Infection prevention and control practitioners
Monitoring and reporting of outbreaks
Epidemiology
What are “other” signs of infection that result from the inflammatory response?
Purulent exudate- pus, phagocytotic WBCs killed in action
Leukocytosis- increase in the number of WBCs
What have we as humans done to contribute to the development of AROs?
Over prescription of antibiotics
People stop taking antibiotics before all the bacteria are killed
How can the spread of MRSA be prevented in hospital settings?
Identify cases by screening patients
Isolate cases
Identify carriers
Eradicate from carriers- intranasal mupirocin
