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23 Cards in this Set
- Front
- Back
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antiseptic
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chemical agent used to kill microorganisms on skin, mucou membranes, or other living tissue
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aseptic (asepsis)
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absence of microorganisms
usually applied to procedures in operating rooms or microbiology labs which involve preventing microorganisms from reaching a protected environment |
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bactericidal
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capable of killing bacteria
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bacteriostatic
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capable of inhibiting bacterial growth
multilication resumes after removal of bacteriostatic agent |
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disinfectant
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any substance used on inanimate objects to kill or inhibit growth of microorganisms
endospores or viruses may not be destroyed disinfectants rreduce or inhibit growth, but do not sterilize |
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germicide
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a chemical agent that kills microorganisms
a bactericide kills bcteria, a sporicide kills endospores, a fungicide kills fungi, a virucide kills viruses, and an amebacide kills amoeba and other protozoans |
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septic (sepsis)
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presence of unwantd microorganisms
usually of pathogens in living tissue |
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sterilization
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process of destroying all forms of microbial life
bacteria, endospores, viruses, fungi must kill spores to be sterilized |
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mechanisms of actions of physical & chemical agents
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membrane damage
protein denaturation & modification nucleic acid damage |
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physical control includes
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heat
filtration radiation |
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heat
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moist
- 100 C - autoclave: 121C, 15 lb/in2, 15 min pasteurization: flash - 71.5 C to 74 C; 15-30 seconds - food borne illnesses arise from plants if inadequate procedure not sterilizing procedures |
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filtration
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liquids: 0.22-0.45 um pores: heat labile liquid
air: high efficiencyy particulate air (HEPA) filters - 99.97% for >0.3 um |
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radiation
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ionizing : x rays, gamma rays, high energy electrons
- DNA & protein damage - free radicals (OH) nonionizing: UV; 260 nm breaks H bonds in DNA b/w T:A - thymine dimers microwaves - heat water; boiling kills vegetative cells |
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chemical control includes
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surfactants
phenol & phenolics alcohols heavy metals & their salts halogens hydrogen peroxide alkylating agents |
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surfactants
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soaps: cleansing agents, net negative charge like bacteria
detergents: polymyxins in triple Abs on skin is similar action - anionic: laundry detergents; not good at killing bacteria - cationic: quaternary ammonium compounds with long phobic tail and net positive charge to penetrate bacterial membrane and be bactericidal |
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phenol & phenolics
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denaturation of proteins; membrane leakage
phenol decreases infections in surgery other phenolics include - hexylresorcinol: can cause neural damage - hexachlorophene - chlorhexidine - triclosan doesn't kill spores |
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alcohols
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ethyl: hand sanitizers
isopropyl |
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heavy metals & their salts
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silver: inactivattes enzymes of bacteria
not much effect on viruses Abs, eye drops, washes, dressings, catheters, tubing, air handling systems decreases hospital infections |
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halogens
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iodine: 2 modes of action
- binds to tyrosine in proteins and disturbs bacterial enzymes - oxidizes sulfhydryl groups: form disulfide bonds & distrubs bact enzyme functions == tincture: 2% I2 + K iodide in alcohol == iodophor: I2+ carrier (cationic detergent or other organic carrier); ex: Wescodyne, betadine (povidone-iodine) chlorine: oxidative activity that unfolds & irreversible aggregates proteins - gas - sodium hypochlorite: bleach is sporicidal - chlorine dioxide (gas): how they sterilized building after anthrax in mail - Chloramine: in water supplies; hot tubs |
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hydrogen peroxide
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oxidizing agent
aqueous solution: e% H202 is cleansing; >35% is sporicidal vaporized: plasma gas sterilization - H202 gas ; sterilizes equipment that you can't autoclave |
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alkylating agents
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aldehydes
- formaldehyde: good as preservative, disinfectent, carcinogenic, sporicidal, acts on amino, sulfhydryl groups, covalently links amino groups & inactivates proteins - glutaraldehyde: disinfectent of heat sensitive instruments; same mode of action |
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ethylene oxide gas
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heat sensitive materials
- very effective, can be exposed at high concentrations, treat heat sensitive instruments to sterilize - kills bacteria, viruses & spores - cyclic structure |
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sporicidal agents
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Glutaraldehyde
formaldehyde iodine compounds chlorine compounds H202 >35% ethylene oxide at low concentrations generally sporostatic, higher concentrations is sporicidal also time dependent |
