Infection Prevention Flashcards
What is an outbreak?
When there are two or more cases linked in time and place.
What is an endemic disease?
When it is at its usual background rate
What is an epidemic?
A rate of infection greater than the usual background rate
What is a pandemic disease?
Very high rates of infection spreading across many regions, countries or continents
What is the basic reproduction number?
Average number of cases one case generates over the course of its infectious period in an otherwise uninfected, non-immune population.
If the basic reproduction number is >1, 1 or <1, what is happening to the number of cases?
R0 >1 - increase in cases
R0 = 1 - number of cases is stable
R0 < 1 - decrease in cases
What are the reasons for outbreaks, epidemics and pandemics?
New pathogen, antigens, virulence factors or resistance
New host - not immune, healthcare effects
New practice - social (eg air con, STIs), healthcare eg surgery
What factors determine transmissibility?
Infectious dose
ID50
What is the infectious dose?
Number of micro-organism required to cause infection
Varies by microorganism, presentation of microorganism, immunity of potential host
What is ID50?
Snakes get dose required to infect 50% of the population.
What a interventions can be done in preventing infection?
Pathogen (and vector) - reduce/eradicate
Patient - improve health and immunity
Practice - behavioural change
Place - environment engineering
How can pathogens be eradicated or reduced?
Antibacterials
Decontamination
Sterilisation
Eliminate vector breeding sites
What can be done with patients to reduce chance of infection?
Nutrition Treatment Immunity -passive -active
Give an example of a way of giving passive immunity
Maternal antibodies
IV immunoglobulin
What is herd immunity
When vaccinated people can protect those who have not been vaccinated
What changes can be done to practice to prevent spread of infection?
Avoid pathogen or vector
PPE
Behaviour - eg safe sex, sharps disposal, food/drink preparation
What changes can be made to a place to prevent spread of an infection?
Safe water Clean air Good quality housing Well-designed healthcare facilities Prevent over-crowding
What are some good consequences of control of infection?
Decreased incidence
Elimination of disease
What are some bad consequences of controlling infection
Decreased exposure to pathogen -> decreased immune stimulus -> decreased antibodies -> increased susceptibility -> outbreak
Later age of exposure can in some cases increase severity of illness
What are some consequences of antibiotic resistance?
Treatment failure
Prophylaxis failure eg for surgery, cancer
Economic costs
What does it mean if a pathogen is multi-drug resistant?
Non-susceptibility to at least one agent in three or more antimicrobial categories
What does extensively drug resistant mean? (XDR)
Non-susceptibility to at least one agent in all but two or fewer antimicrobial categories
What is antimicrobial stewardship?
Appropriate use of antimicrobials to achieve optimal clinical outcomes
minimise toxicity and other adverse events
reduce cost of healthcare infections
limit selection for antimicrobial resistant strains
What are the elements of the stewardship programme?
Multidisciplinary team
Surveillance (process measures and outcome measures)
Interventions
How is the stewardship programme carried out?
Persuasive - education, reminders, audit, feedback
Restrictive - restricted susceptibility reporting, formulary restriction, prior authorisation
Structural - computerised records, rapid lab tests, expert systems, quality monitoring
What are process measures?
Looking at quantities of drugs used, appropriateness, and benchmark institutions against others
What are outcome measures?
Patient outcomes, emergence of resistance, C. diff infection rate
What does successful stewardship require?
Long term confirmed and appropriate resources
Hospital leadership support, delegated authority to challenge inappropriate antimicrobial therapy
Integration into patient safety and quality of care structures and processes.
What are some unintended consequences of the stewardship programme?
Readmission risk slightly increased
