Infection Prevention And Antimicrobial Stewardship Flashcards
How does legionella pneumophila spread?
Aerosol and droplets
Not transmissible form person to person
How do ‘food poisoning’ organisms generally spread?
Lots of person to person transmission
Faecal-oral transmission
Name some infections with very good person to person spread
Influenza
Norovirus
Neisseria gonorrhoea
How does the guinea worm spread?
In water
Into people
Back into water
What is the vector of schistosomiasis?
Snails
Define endemic
The usual background rate of a disease (expected amount)
Define outbreak
2 or more cases linked in time and place
Define epidemic
Rate of infection greater than usual background rate
Define pandemic
Very high rate of infection spreading across many regions, countries and continents
What is R0?
The average number of secondary cases that one case generate over its infectious period
What is the approximate R0 for influenza?
2 - 3
What are the general reasons for outbreaks/epidemics/pandemics?
New pathogen
New hosts
New practice (social/healthcare)
Define antigenic drift
Subtle change by mutation
Some antibodies may still be effective
Define antigenic shift
Reassortment of DNA of virus
No one is immune (everyone susceptible)
How long are maternal antibodies present in a newborn?
~ 3 months
Define infectious dose
The number of microorganisms required to cause infection
Varies by microorganism, presentation and immunity of host
PPIs suppress acid secretion, therefore which food poisoning agents are you at more risk of being infected with?
Clostridium difficile
Salmonella
Epidemic curves are usually what shape?
Bell curve (Time = x, no of people infected = y)
When will abnormal population curves of infection occur?
In small scale outbreaks
Eg. In a family, ward, prison
Due to random nature of events
When do maternal antibodies move across the placenta?
Last 4 weeks of pregnancy
Describe herd immunity
Vaccinating a significant portion of the population will prevent widespread disease
Fewer infected even though not vaccinated
Why can decreased exposure to pathogens become a problem?
Decreased exposure -decreased immune stimulus
Decreased antibodies
Increased susceptibility
Can lead to outbreaks
Is resistance reversible?
No
What are the consequences of Abx resistance?
Treatment failure
Prophylaxis failure - eg. Operations
Economic costs - longer hospital stay, extra investigations needed
