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55 Cards in this Set
- Front
- Back
Sepsis |
Microbial contamination |
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Asespsis |
Absence of significant contamination |
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Aseptic surgery technique |
Prevent microbial contamination of wounds |
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Sterilization |
Removal of all microbial life |
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Commericial sterilzation |
Killing C botulinum endospores in canned food |
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Disinfection |
Removal of pathogens |
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Antisepsis |
Removal of pathogens from living tissue |
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Degerming |
Removal of microbes from a limited area |
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Sanitization |
Lower microbial counts on eating utensils |
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Biocide/Germicide |
Kills microbes |
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Bacteriostasis |
Inhibting, not klling, microbes (refrigerator) |
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One log decrease |
90 percent of population killed |
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Bacterial population death |
Constant logarithmic rate when treated |
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Effectiveness of antimicrobial treatment |
Number of microbes Environment (organic matter, temperature, biofilms) Time of exposure Microbial characteristics (capsules/spores) |
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Action of Microbial Control agents |
Alternation of permeable membrane-Damage to plasma membrane Damage to proteins-especially enzymes Damage to nucleic acids - DNA or RNA |
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Heat: Thermal Death Point |
Lowest temperature at which all cells in a culture are killed in 10 min. Lower temp may not damage vitamins or antibiotics or damage products |
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Heat: Thermal Death Time |
Time to kill all cells in a culture |
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Decimal reducton time |
Minutes to kill 90% of a population at a given temperature |
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DRT or D Value |
Decimal Reduction time |
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Moist Heat |
Denatures proteins (breaks hydrogen bonds between nucleotides) boiling |
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Autoclave |
Steam under pressure |
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Steam sterilization |
Steam must contact item's surface Steam does pass through foil Use paper to wrap objects Use sterility indicators (tape or spore vials) |
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Pasteurization |
Reduces pathogenic microbes which elimates spoilage.
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Equivalent pastuerization treatments |
63C for 30 min traditionally High temperature, short time: 72C for 15 sec Ultra high tempature: 140C for <1sec Thermoduric organisms survive |
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Dry heat |
Sterilizaiton kills by oxidation Flaming, Incineration, Hot air sterilization Hot air 170C @ 2 hours = Autoclave 121C @ 15 min |
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Filtration |
Removes microbes |
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Low Temperature |
Inibits microbial growth Doesn't work on Listeria Slow deep freezing ruptures cells Lyophilization |
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High pressure |
Denatures proteins |
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Desiccation |
prevents metabolism |
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Osmotic pressure |
Causes plasmolysis - High salt or sugar levels |
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Radiation |
Damages DNA. |
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Ionizing radiation |
X rays gamma rays, electron beams |
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Nonionizing radiation |
UV |
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Microwaves |
Kill by heat, not especially antimicrobial |
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Principles of effective disinfection |
Concebtration of disinfectant, Organic matter, pH, Time |
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Evaluation of a disnfectant |
Diluation test 1. Metal rings dipped in test bacteria are dried. 2. Dried cultures are placed in disinfectant for 10 min at 20C 3. Rings are transferred to culture media to determine whether bacteria survived treatment |
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Phenotics |
Lysol |
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Bisphenols: Hexachlorophene, Triclosan |
Soaps and toothpast - disrupt plasma membranes |
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Biguanides: Chlorhexidine |
Disrupt plasma membrane. Surgical hand scrubs when combined with alocohol Microbial control skin/mucous membrane up to 6 hours |
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Halogens: Iodine, chorline |
Oxidizing agents Bleach is hypochlorous acid |
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Alochols: Ethanols, isopropanol |
Denature proteins, dissolve lipids Not good for wounds-coagulated Skin degermination |
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Heavy Metals: Ag, Hg, and Cu |
Oligodynamic action - metals exerting antimicrobial activityy ex. Silver nitrate solution Denature proteins |
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Surface-active agents or surfactants |
Decrease surface tension molecules |
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Soap |
Degerming |
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Acid-anionic detergents Dairy industry |
Santinzing |
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Quarternary ammonium compounds, Cationonic detergents, Used in moutwash |
Bactericidal, Denature proteins, disrupt plasma membrane |
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Chemical food preservatives |
organic acids Nitrite Antibiotics |
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Organic Acids |
Inhibit metabolism Sorbic Acid, Benzoic acid, and calcium propionate Control molds and bacteria in foods and cosmetics |
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Nitrite |
Prevents endospore germination used in meat |
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Antibiotics |
Nisin and natamycin prevent spoilage of cheese |
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Aldehydes |
Inactivate proteins by by cross linking with funcitonal groups
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Gaseous sterilants |
Denature proteins Ethylene oxide |
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Peroxygens |
Oxidzing agents O3, H2O2, peracetic acid Benzoyl peroxide |
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Most Resistant Microbe |
Prions |
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Least Resistnat Microbe |
Viruses with lipid envelops |