Infection Prevention
Scope
Infection prevention is tested as a chain, a set of precautions and a set of waste rules. You must know which practice breaks which link.
Chain of infection
Six links: infectious agent → reservoir → portal of exit → mode of transmission → portal of entry → susceptible host. Breaking any one link prevents infection; hand hygiene mainly attacks transmission.
Core rules
- WHO 5 Moments for hand hygiene: before touching a patient; before a clean/aseptic procedure; after body-fluid exposure risk; after touching a patient; after touching patient surroundings.
- Handrub 20–30 seconds with an alcohol-based formulation; handwash 40–60 seconds with soap and water when hands are visibly soiled or after caring for a patient with C. difficile.
- Donning: gown → mask → goggles → gloves. Doffing: gloves → goggles → gown → mask, with hand hygiene after each step. Gloves never replace hand hygiene.
- Biomedical waste (India, BMW Rules 2016): yellow - anatomical waste, soiled waste, expired medicines, chemical waste; red - contaminated recyclable plastic such as IV tubing, bottles and gloves; white (translucent) - sharps, needles, blades; blue - glassware and metallic implants.
- Sterilisation kills spores (autoclave 121 °C, 15 psi, 15–20 minutes); disinfection reduces organisms but may not kill spores.
- Never recap a needle; dispose of it immediately in the sharps container at the point of use.
Worked example
A nurse sustains a needle-stick after an IM injection. Reasoning: encourage bleeding under running water, wash with soap, do not squeeze or suck, apply antiseptic and a watertight dressing; report to the infection-control nurse immediately, recording time, source and immune status; take baseline blood tests; HIV post-exposure prophylaxis should start as early as possible, ideally within 2 hours, with follow-up testing at 6 weeks, 3 months and 6 months; check hepatitis B vaccination status.
Traps that cost marks
Removing the mask before the gloves; putting needles in the red bag; using handrub on visibly soiled hands; recapping needles "to avoid injury"; assuming sterile gloves remove the need for hand hygiene.