Infection Prevention and Chain of Transmission
Break one link and the chain fails
The chain of transmission has six links: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host. Environmental services intervenes hardest at the reservoir (cleaning and disinfection) and the mode of transmission (hand hygiene, PPE, isolation technique).
Standard precautions come first
Standard precautions apply to every patient, every time, because any patient may be colonized. Hand hygiene is the single most effective intervention: alcohol-based rub for routine use, soap and water when hands are visibly soiled and for C. difficile and norovirus, because alcohol does not reliably inactivate those organisms. Gloves never replace hand hygiene.
Transmission-based precautions
- Contact - MRSA, VRE, CRE, C. difficile, scabies. Gown and gloves; dedicated or cleaned equipment.
- Droplet - influenza, pertussis, mumps, rubella. Surgical mask when within the patient's zone.
- Airborne - tuberculosis, measles, varicella. Fit-tested N95 or higher respirator plus a negative-pressure room with the door closed.
PPE order
Donning: gown, mask or respirator, goggles or face shield, gloves last. Doffing: gloves, face shield or goggles, gown, then mask or respirator - removed by the straps, never the front - followed by hand hygiene.
Traps
Questions swap droplet and airborne (flu is droplet; measles and TB are airborne), show a technician reaching for alcohol rub in a C. diff room, or have someone prop open an airborne isolation door. Never prop an airborne infection isolation room door, never wheel a clean cart into a soiled utility room, and never carry a soiled cloth out of a room uncovered.
Rule of thumb
Ask before you enter: what am I protecting - me, the next patient, or both? If the answer involves a respirator, the door must close behind you.