Infection Control and Microbiology: Chain, Hygiene, and Waste
What this domain tests
Chain of infection, hand hygiene, PPE, sterilisation and disinfection, waste segregation, and common pathogens.
Core rules and concepts
- Chain: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host. Break any link to prevent infection.
- Hand hygiene: before touching a patient, before clean/aseptic procedure, after body-fluid exposure, after touching a patient, after touching patient surroundings.
- PPE: gloves, gown, mask, eye protection. Remove gloves first, then goggles/gown, mask last; perform hand hygiene after.
- Sterilisation kills all microorganisms including spores; disinfection reduces pathogens but may not kill spores.
- Biomedical waste: yellow (infectious), red (contaminated recyclable), white (sharps), blue (glassware).
Worked example
A nurse sustains a needlestick injury. Reasoning: wash the wound with soap and running water, do not squeeze or scrub, report immediately, and assess the source and the nurse's hepatitis B and HIV status. Post-exposure prophylaxis should be started as soon as possible if indicated.
Traps that cost marks
- Using alcohol rub for visible blood or for C. difficile spores; wash with soap and water.
- Recapping needles.
- Putting sharps in a red bag.
- Wearing the same gloves for two patients.