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24 Cards in this Set
- Front
- Back
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sterilization
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the process of destroying all forms of life
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3 main methods of sterilization
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killing by use of heat
chemicals removal by filtration |
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factors influencing sterilzation by heat
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1.temperature and time of exposure
2. presence or absence of water 3. number of microbes 4. species and strain of microbe 5. nature of contaminated material -high content of organic material protects organisms -fats/oils prevent access of moisture |
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methods of sterilization by dry heat
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1. burning (incineration)
-red heat, burn carcasses, and organic material 2. flaming -not red heat 3.hot air oven -sterilizes glass ware, swabs, powders, fats and oils 4. pasteurization |
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methods of sterilization by moist heat
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1. boiling water
-place material in a water bath, bring water to a boil, hold at boiling temp for 10 minutes and then turn off -does not destroy spores 2. free flowing steam -single exposure or intermittent exposure at 100 C for 20-45 minutes 3. steam underpressure -saturated steam under pressure -rapid heating, pentratiion and abundant moisture |
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4 types of autoclaves
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1. simple, nonjacketed
2. steam jacketed, automatic air and condensate discharge 3. vacuum 4. high pressure |
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what precautions should be kept in mind when useing the autoclave
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1. discharge of air must be complete
2. decrease in pressure -causes a decrease in temp, you must start timing over again 3. opeing the door -must be done gradually -careful not to scald on the steam 4. proper loading -permit proper steam passage |
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methods to check autoclave efficiancy
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1. recording charts
2. indicators -biological (spore strips, ampoules of bacteria) -chemical (color change) 2. gauges 3. thermometers |
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what parts of the bacterial cell are susceptible to attack?
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cell membrane or cell wall
enzymes nuclear material proteins |
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characteristics of ideal disinfectant
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1. high coefficient of disinfection
2. stability 3. solubility 4. nontoxic 5. homogeneity 6. non corrosive, non bleaching, non staining 7. antimicrobial at room temp 8. high penetrating ability 9. noncombinging with extraneous organic material 10. detergent capability 11. deodorizing power 12. ease of application |
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8 types of disinfectants
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alcohols
quats organic compounds oxidizing agents gases heavy metals aldehydes soaps and detergents |
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alcohols
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methyl and ethyl
70% concentratino most often used -kills all vegetative cells -not sporicidal -denatures proteins and dissolves lipids |
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quats
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quaternary ammonium compounds
-soap like properties -kills all vegetative forms except some Pseudomonas -non sporicidal -non tuberculocidal |
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organic compounds
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phenol and phenolyic compounds
-non sporicidal but are tuberculocidal -best as surface disinfectants -denatures cell proteins and cell membranes |
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oxidizing agents
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halogens-oxygen, iodine, bromine and flourine
-iodine is sporicidal, highly effective -chlorine-sporicidal |
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heavy metals
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in small amounts, metals can distroy bacteria
-soluble froms of mercury, arsenic, silver, copper, zinc -better antiseptics than disinfectants -bacteriostatic |
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aldehydes
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denature proteins
- gluteraldehyde, formaldehyde (aqueous and gaseous) |
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gases
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used when you can use high temps or chemicals for sterilizing plastic, heat sensitive items
-ethylene oxide -sporicidal -requires long airing out time |
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soaps and detergents
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surface cleaners
-best for removal of microorganisms -not germicidal |
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sterilization by filtration
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removal of microbes from liquids or air by filtering
-membrane filters, face masks, cotton or gauze |
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ultraviolet light
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cause cell death by inducing damage in the cell's DNA
-must be direct contact -sterilize surfaces, air and sometimes water |
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disadvantages to uv light
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harmful to the eyes
harmful to skin does not penetrate material well |
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ionizing radiation
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gamma radiation
-penetrates very well -very short wavelength and high energy -very harmful to microorganisms -cold sterilization of antibiotics, hormones, sutures, cosmetics -sterilize plastic disposable items |
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drying
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removes moisture microbes need to dissolve their nutrients
-used for food and fabric |
