NEET PG High-Yield: Disinfection & Sterilization
Distinguishing between sterilization (killing all microorganisms, including spores) and disinfection (reducing pathogens to a safe level) is a frequent exam topic.
Key Definitions & Methods
| Level | Scope | Examples |
|---|---|---|
| Sterilization | Kills ALL microbes (including spores). | Autoclaving, Gamma radiation, Ethylene oxide. |
| High-Level Disinfection | Kills everything EXCEPT high numbers of spores. | Glutaraldehyde (2%), Hydrogen peroxide. |
| Intermediate/Low | Kills vegetative bacteria, most fungi/viruses. | Alcohol (70%), Phenols, Chlorine. |
High-Yield NEET PG Pearls:
- Autoclave: Gold standard for metallic instruments; 121°C for 15-20 minutes at 15 psi.
- Spore Test: Bacillus stearothermophilus is used to monitor autoclave efficacy.
- Glutaraldehyde: The “Cold Sterilizer” of choice for heat-sensitive equipment (e.g., endoscopes).
- Formaldehyde: Used for fumigation of operating theatres.
- Pasteurization: Not sterilization; it kills non-sporing pathogens in milk.