STERILIZATION AND DISINFECTION

1. STERILIZATION AND DISINFECTION CHAPTER 7

2. Terminology • Disinfection: Reducing the number of pathogenic microorganism in or on an object so that they pose no threat of disease • Disinfectant: Applied to inanimate object • Antiseptic: Applied to living tissue • Sterilization: Killing or removing all microorganism in or on an object

3. Chemical Antimicrobials - Potency

4. Chemical Antimicrobials - Potency The Filter Method Staphylococcus aureus(G+) Escherichia coli (G-)

5. Time of action Fast acting Safety Without destroying tissue Microbe range Broad Penetration Withot damage or discolor the material Preparation Easy and stable with light, heat etc Cost Inexpensive Odor No unpleasant odor Disinfectant Selection Criteria

6. Mechanisms of Action • Protein denaturation and degradation

7. Mechanisms of Action • Membrane damage

8. Disinfectant Types • Soaps/detergents • Alcohols • Quats • Acids/Alkalis • Phenols • Heavy Metals • Oxidizing Agents • Halogens • Ethylene Oxide • Dyes • Salt

9. Disinfectants (cont.) Hydrogen peroxide disinfection Vaporized H2O2 sterilizes small, sealable spaces such as hood and transfer room. Not enough for operating rooms

10. Ethylene oxide chamber It is explosive and carcinogenic.

11. Physical Antimicrobial Agents • Heat Application • Dry Heat: Oven or open flame • 171°C for 1 hour • 160 °C for 2 hours • 121 °C for 16 hours • Moist Heat: Autoclav • 121 °C, 15bl/in2 for 15 to 20 minutes until the indicator shows change • Pasteurization – Salmonella & Mycobacterium in Milk and Beer • 71.6°C for 15 minutes • 62.9°C for 30 minutes

15. The Autoclave

18. Refrigeration/Freezing Dessication Freeze-drying Physical Antimicrobial Methods

19. Drying Physical Antimicrobial Methods

21. Radiation Physical Antimicrobial Methods

22. Physical Antimicrobial Methods • Filtration