Infection Prevention & Control
Chain of infection, when to use which precautions, and the moments hand hygiene actually matters.
Why this comes before everything else
Healthcare-associated infections are the complication you cause. Everything else on a unit — falls, medication errors, pressure injuries — has some component outside your control. Transmission almost never does.
The exam tests this constantly, and it tests it as a priority question: given four reasonable actions, which one prevents transmission.
The chain of infection
Infection needs all six links. Break any one and transmission stops.
| Link | What it is | Where you break it |
|---|---|---|
| Infectious agent | The organism | Antimicrobials, sterilisation |
| Reservoir | Where it lives | Cleaning, disposing of waste |
| Portal of exit | How it leaves | Covering coughs, dressings |
| Mode of transmission | How it travels | Hand hygiene, PPE |
| Portal of entry | How it gets in | Aseptic technique, line care |
| Susceptible host | Who it infects | Immunisation, nutrition |
Mode of transmission is the link nurses break most often, which is why hand hygiene is the answer to more questions than anything else in this topic.
The five moments for hand hygiene
- Before touching a patient
- Before a clean or aseptic procedure
- After body fluid exposure risk
- After touching a patient
- After touching patient surroundings
Moments 1 and 4 protect the patient. Moment 2 protects them from their own flora. Moments 3 and 5 protect you and the next patient.
Alcohol rub or soap and water? Alcohol for most situations — it's faster and more effective against most organisms. Soap and water when hands are visibly soiled, and for C. difficile and norovirus, because alcohol does not kill spores.
Precautions
Standard precautions apply to every patient, every time, regardless of diagnosis. You do not need to know someone is infectious to use them.
| Type | Examples | PPE |
|---|---|---|
| Contact | MRSA, VRE, C. diff, scabies | Gown + gloves |
| Droplet | Influenza, pertussis, meningococcal | Surgical mask, eye protection |
| Airborne | TB, measles, varicella | N95, negative pressure room |
C. difficile is contact precautions plus soap and water, not alcohol. That combination is a very common exam question.
Donning and doffing
Putting on: gown → mask → goggles → gloves. Taking off: gloves → goggles → gown → mask.
The logic is that gloves are dirtiest, so they come off first, and the mask comes off last because you are still in a contaminated space until you leave. Perform hand hygiene after removing all PPE, even though you wore gloves.
Where transmission actually happens
- Stethoscopes and phones carried between rooms
- Failing to change gloves between tasks on the same patient
- Touching a chart or keyboard with contaminated gloves
- Long sleeves, rings, and watches
- Reaching into your pocket mid-procedure
Escalate
Report suspected outbreaks, unexpected clusters, and any needlestick or splash exposure immediately — exposure prophylaxis is time-sensitive.