Week 8 - Infection Prevention and Antimicrobial stewardship Flashcards
What are the measures of infection cases?
- Endemic: the usual background rate
- Outbreak: 2 or more cases linked in time and place
- Epidemic: a rate of infection greater than the usual background rate
- Pandemic: very high rate of infection spreading across many regions, countries and continents
What is the basic reproduction number, R0?
The average number of cases 1 case generates over the course of its infectious period, in an otherwise uninfected, non-immune population
- R0 > 1 → increase in cases
- If R0 = 1 → stable number of cases
- If R0
What are some reasons for outbreaks, epidemics or pandemics?
- New pathogen
— Antigens
— Virulence factors
— Antibacterial resistance - New hosts
— Non-immunes
• Increased number of diabetics
• Increased number of chemotherapy patients
• Increased number of elderly people
• Increased number of births
— Healthcare effects - New partners
— Social
• E.g. Increased number of sexual partners
• E.g. decreased use of contraception
— Healthcare
• E.g. Increased bed occupancy rates leads to an increase in the number of c. diff infections
What factors determine transmissibility?
- Infectious dose: number of micro-organisms required to cause infection
— Varies by:
• Micro-organism
• Presentation of micro-organism
• Immunity of potential host - Epidemic curves
— The number of people affected at each time interval is plotted against time
— There is a stochastic nature to small scale outbreaks
What infection prevention methods could be applied to the pathogen/vector?
- Reduce/eradicate pathogen
- – Antibacterials including disinfectants
- – Decontamination
- – Sterilisation
- Reduce/eradicate vector
- – Eliminate vector breeding sites
What infection prevention methods could be applied to patients?
- Improve health
— Nutrition
— Medical treatment - Immunity
— Passive
• E.g. maternal antibody, IV immunoglobulin
— Active, i.e. vaccination
What infection prevention methods could be applied to practice?
- Geographic
— Don’t go there! - Protective clothing/equipment
— Long sleeves/trousers against mosquitoes
— PPE in hospitals
• E.g. gowns, gloves, masks - Behavioural
— Safe sex
— Safe disposal of sharps
— Food and drink preparation
What infection prevention methods could be applied to place?
Environmental engineering:
- Safe water
- Safe air
- Good quality housing
- Well designed healthcare facilities
What are some consequences of infection control?
Good:
- Decreased incidence or elimination of the disease/organism
— E.g. smallpox, polio
Bad:
- Decreased exposure to pathogen means there is a reduced immune stimulus
— Hence there is decreased antibodies, so increased susceptibility
— Can lead to an outbreak
- Later average age of exposure can increase the severity
What are some consequences of antimicrobial resistance?
- Treatment failure
- Prophylaxis failure
- Economic costs
What are some definitions for antimicrobial resistance?
- Multi-drug resistant: non-susceptibility to at least 1 agent in 3 or more antimicrobial classes
- Extensively-drug resistant: non-susceptibility to at least 1 agent in all but 2 or fewer antimicrobial categories
- Pan-drug resistant: non-susceptibility to all agents in all antimicrobial categories
What are the objectives of antimicrobial stewardship?
- Appropriate use of antimicrobials
- Optimal clinical outcomes
- Minimise toxicity and other adverse events
- Reduce the costs of health care for infection
- Limit the selection for antimicrobial resistant strains
What are the different types of antimicrobial stewardship?
- Persuasive:
- – Education
- – Consensus
- – Opinion leaders
- – Reminders
- – Audit
- – Feedback
- Restrictive:
- – Restricted susceptibility reporting
- – Formulary restriction
- – Prior authorisation
- – Automatic stop orders
- Structural:
- – Computerised records
- – Rapid lab tests
- – Expert systems
- – Quality monitoring
