1. Sterilization And Disinfection G. Jamjoom

2. Disinfection: Use of physical procedures or chemical agents to destroy most microbial forms; bacterial spores and other relatively resistant organisms (e.g., mycobacteria, viruses, fungi) may remain viable; disinfectants are subdivided into high-, intermediate-, and low-level agents Antisepsis: Use of chemical agents on skin or other living tissue to inhibit or eliminate microbes; no sporicidal action is implied Definitions Sterilization: Use of physical procedures or chemical agents to destroy all microbial forms, including bacterial spores

3. Germicide: Chemical agent capable of killing microbes; spores may survive High-level disinfectant: A germicide that kills all microbial pathogens except large numbers of bacterial spores Intermediate-level disinfectant: A germicide that kills all microbial pathogens except bacterial endospores Low-level disinfectant: A germicide that kills most vegetative bacteria and lipid-enveloped or medium-size viruses Sporicide: Germicide capable of killing bacterial spores

6. STERILIZATION All living things killed, All living things killed, including spores including spores

7. Sterilization autoclavingautoclaving –121 o C (heat/pressure) *Heat resistant materials ethylene oxideethylene oxide –Non heat resistant – usually equipment ultra-violet lightultra-violet light – surfaces (e.g operating rooms) – not totally effective

8. Disinfection Liquids that kill bacteriaLiquids that kill bacteria –e.g. phenol based –too toxic for skin surfaces

9. Antiseptics Topical (e.g. skin) Topical (e.g. skin) – e.g. iodine or 70% alcohol – “reduce” bacterial load

10. Concentration or LevelMethod Physical Sterilants 121 C or 132° C for various time intervals Steam under pressure 1 hr at 171° C; 2 hr at 160° C; 16 hr at 121° C Dry heat 0.22 - to 0.45-μm pore size; HEPA filters Filtration Variable exposure to 254-nm wavelength Ultraviolet radiation Variable exposure to microwave or gamma radiation Ionizing radiation Methods of Sterilization

12. Membrane filters pores bacteria

13. Gas Vapor Sterilants 450-1200 mg/L at 29° to 65° C for 2-5 hr Ethylene oxide 2% - 5% at 60° to 80° CFormaldehyde Formaldehyde vapor 30% at 55° to 60° CHydrogen peroxide vapor Highly ionized hydrogen peroxide gas Plasma gas Chemical Sterilants 0.2%Peracetic acid 2%Glutaraldehyde Methods of Sterilization

14. Table 10-1. Methods of SterilizationTable 10-1. Methods of Sterilization Concentration (Level of Activity)Method Heat 75 to 100° C for 30 min (high)Moist heat Liquid 2% (high)Glutaraldehyde 3% - 25% ( high )Hydrogen peroxide 3% - 8% (high/intermediate)Formaldehyde Formaldehyde Variable (high)Chlorine dioxide Variable (high)Peracetic acid 100 - 1000 ppm of free chlorine (high)Chlorine compounds 70% - 95% intermediate)Alcohol (ethyl, isopropyl) 0.4% - 5% intermediate/low)Phenolic compounds 30 50 ppm of free iodine/L (intermediate)Iodophor compounds 0.4% - 1.6% low)Quaternary ammonium compounds Methods of Disinfection

15. ConcentrationAntiseptic Agent 70%-90%Alcohol (ethyl, isopropyl) 1-2 mg of free iodine/L; 1%-2% available iodine Iodophors 0.5% - 4%Chlorhexidine 0.5% - 3.75%Parachlorometaxylenol 0.3% - 2.0%Triclosan Antiseptic Agents

16. VirusesFungiBacterial SporesMycobacteriaBacteriaAgents Disinfectants +/-+-++Alcohol +++/-++Hydrogen peroxide +++++Formaldehyde Formaldehyde +/-+-++Phenolics +++/-++Chlorine ++-+/-+Iodophors +++++Glutaraldehyde +/- -- Quaternary ammonium compounds Antiseptic Agents ++-++Alcohol ++-++Iodophors ++-++Chlorhexidine +/-+- Parachlorometaxylenol ++/-- +Triclosan Germicidal Properties of Disinfectants and Antiseptic Agents