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25 Cards in this Set
- Front
- Back
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filter paper method
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1. spread microorganism on agar
2. place discs containing a disinfectant on agar 3. incubate 4. look for zones of inhibition of growth |
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phenols
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denature proteins and disrupt plasma membranes
bactericidal or bacteriostatic o-phenylphenol, hexachlorophene |
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biguanide group - chlorhexidine
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complex organic compound that contains chlorine
used in surgical hand scrubs bactericidal, not sporicidal ONE OF THE BEST |
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iodine
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skin wounds
bactericidal, sporicidal acts as oxidizing agent: pulls electrons off tyrosine, iodinates it. inactivates that protein |
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iodine in solution
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tincture of iodine
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iodophors
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iodine complexed to an organic compound
less irritating to skin |
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chlorine
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used over 200 years - Semmelweis
gas, hypochlorites, chloramines combines with water & releases hypochlorous acid - oxidizing agent sodium hypochlorite = bleach, disinfectant |
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alcohol examples
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ethanol, isopropanol
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what do alcohols do?
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denature proteins, act on lipids of membranes and virus envelopes
bactericidal & fungucidal NOT sporicidal tincture of iodine = iodine in alcohol |
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heavy metals
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Ag, Hg, Zn, Cu
denature proteins act on -SH groups of proteins bactericidal antiseptics |
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silver
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silver nitrate is used in eyes of new borns to prevent infection
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copper
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copper sulfate is used to kill algae in ponds, swimming pools..
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zinc
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zinc chloride is used in mouthwashes
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mercury
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mercuric chloride = bacteriostatic & toxic
mercurochrome = mercury complexed to an organic compound |
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surface-active agents (surfactants)
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decrease surface tension
SOAPS, detergents salts of fatty acids act on membranes of cells and emulsify lipids. break up lipids of membraes, decreasing surface tension of membrane. |
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what are quats?
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quaternary ammonium compounds
benzalkonium chloride |
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what do quats do?
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disrupt membranes
bacterial against gram-positive negative (p. aeruginosa) grows in some quats used in hospitals restrooms inexpensive, stable, nontoxic, can be mixed with alcohol |
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chemical food preservatives (organic acids)
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inhibit enzymes. biofeedback mechanisms.
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chemical food preservatives examples
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Sorbic acid in acidic foods
Benzoic acid in acidic foods (soft drinks) Parabens in cosmetics and shampoos Calcium propionate used in breads. |
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aldehydes
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formaldehyde & glutaraldehyde
have -HC=O group cross linking amino acids |
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formaldehyde
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was gas, now formalin solution
irritates skin |
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glutaraldehyde
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used to sterilize hospital instruments
bactericidal, tuberculocidal, virucidal in 10 mins. can be spirocidal only liquid sterilizing agent ! |
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ethylene oxide
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gas
denatures proteins sterilizes without heat good for plastics & sensitive items like books |
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peroxygens
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oxidizing agents - macromolecules
ozone instead of chlorine in water hydrogen peroxine (H2O2) antiseptic used on skin, disinfectant for contact lenses benzoyl peroxide - used for acne |
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more vs less resistant
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gram + > gram -
endospores are highly resistant mycobacteria are relatively resistant cuz of their waxy lipids outside their cell wall enveloped viruses (HIV) least resistant than non-envelope viruses |
