Healthcare Acquired Infections Flashcards
What is the definition of a HAI?
Infection develops >48h post-admission or within 48h of discharge
What are some potential outcomes of HAI?
- Extended stay
- Pain/Discomfort
- Disability
- Death
What are the most common sites of HAI?
UTI (catheters) Surgical Site Infection RTI (intubation) Blood Stream (CV catheter) GI (c. diff) Skin/Soft Tissue
What is the difference between colonisation and infection?
Bacteria are everywhere. Colonisation is the presence of bacteria harmlessly without causing symptoms.
Infection is when bacteria are present and by proliferation or spread to sterile areas cause illness and symptoms.
What factors may tip the balance of bacteria-host equilibrium from colonisation to infection?
Microbial Factors:
- Resistance
- Virulence
- Transmissability
- Survival
- Evasion Mechanisms
Host factors:
- Devices/Foreign Bodies
- Abx/Immunosuppression
- Skin Breaks
- Age Extremes
- Overcrowding
- Increased Opportunity
What different means of transmission are there?
Direct contact - usually staph aureus and coliforms
Respiratory/Droplet - neisseria meningitidis, mycobacteria tuberculosis
Faecal-Oral - C. diff, salmonella
Penetrating injury - group A strep, bloodborne virus
What are the differences between Cleaning, Disinfection and Sterilisation?
Cleaning - Physical removal of organic material/decrease in microbial load.
Disinfection - Large reduction in microbe numbers (spores remain)
Sterilisation - Removal/Destruction of ALL microbes and spores
What are the 3 key parts of the chain of infection?
Source of microbe (endogenous vs exogenous)
Transmission
Host
How can we break the chain of infection?
Risk awareness SICPs Hand Hygeine PPE Vaccination Post-exposure prophylaxis Environment
How do we achieve cleaning?
Detergent, water and drying - used for low risk - intact skin contact, stethoscopes etc
How do we achieve disinfection?
Heat - pasteurisation and boiling
Chemical - alcohol, chlorhexidine, hypochlorites, hydrogen peroxide
For medium risk mucous membrane contact and endoscopes
How do we achieve sterilisation?
Autoclave , gas, ionising radiation, hot air oven.
Used for high risk surgical instruments.
What is an outbreak?
2 or more cases of infection linked in time and place
How do we identify an outbreak?
Act on suspicion and type to make sure the same strain is present. This may be done by: antiobiogram phage typing (SA) pyocin typing (pseudomonas) serotyping (salmonella, pseudo) Molecular typing
How do we control an outbreak?
Single room isolation Cohort cases Ward closure Reinforcement of IPC measures Staff exclusion Staff decolonisation
