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59 Cards in this Set
- Front
- Back
Sepsis (Greek for decay or putrid) |
Bacterial Contamination as in (septic tank) |
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Asepsis |
the absence of significant contamination |
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Sterilization |
- the removal or destruction of al lliving microorganisms, including endospores but with the possible exceptions of prions - steam autoclave |
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Sterilant |
- a sterilizing agent |
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sterile |
a characteristic of being free of all living things |
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Commercial Sterilization |
- limited heat treatment to food, just enough to kill endospores of that produce a deadly toxin |
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Disinfection |
Destruction of vegetative pathogens on inanimate objects - may use chemical, ultraviolet radiation, boiling water, or steam - cavicide |
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a disinfectant
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a chemical used to treat an inert surface or substance in order to destroy vegetative pathogens |
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Antisepsis |
Destruction of vegetative pathogens on living tissues - treatment is almost always by chemical antimicrobials |
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an antiseptic |
a chemical used to treat living tissue in order to destroy vegetative pathogens - betadine |
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Degerming |
Removal of microbes from a limited area, such as the skin around an injection site. - mostly a mechanical removal by an alcohol-soaked swab |
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Sanitization |
Treatment is intended to lower microbial counts on eating and drinking utensiles to safe public health levels - may be done with high-temp washing or dipping into a chemical disinfectant |
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- cide |
- suffix of treatments that cause the outright death of microbes -ie. virucide: inactivates viruses germicide/biocide: kills microorganisms fungicide: kills fungi |
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- stasis |
- suffix of treatments that inhibit the growth and multiplication of microbes - many important control methods are static rather than cidal - fungistatic -bacteriostatic |
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Describe the patterns of microbial death caused by treatments with microbial control agents |
- Bacterial populations usually die at a constant rate when heated or when treated with antimicrobial agents, microbes die at a logarithmic rate, not all the same time - it is necessary to use logarithmic numbers to graph baceterial populations effecetively |
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Explain what is meant by the statement: Bacterial populations usually die at a constant rate |
This means that the same percentage of survivors dies during each equal time period (they do not all die at the same time) |
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Describe the generalized effects of microbial control agents on cellular structures |
1. Alteration of Membrane Permeability: damage to lipids or proteins of the plasma membrane causes cellular contents to leak into the surrounding medium and interferes with growth of the cell |
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Describe the generalized effects of microbial control agents on cellular structures |
2. Damage to Proteins of Nucleic Acids: the breaking of hydrogen bonds by heating or chemicals causes denaturation of proteins. Damage to the nucleic acids prevents cells from replication or creating enzymes. |
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Moist Heat |
- moist heat kills microbes by coagulating proteins (denaturation) by breaking hydrogen bonds. |
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Moist Heat: Boiling at 100° C
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- disinfection (cannot be relied upon to kill spores) |
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Moist Heat: Flowing Steam at 100° C |
- disinfection (cannot be relied upon to kill spores) |
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Moist Heat: Steam Under Pressure |
- the function of pressure is to raise boiling point of water - sterilization: should kill spores, viruses, etc - 15psi = 121° C for 15mins. |
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Moist Heat: Pasteurization |
- eliminate microbes that cause spoilage and pathogenic microbes by heating. Invented by Louis Pasteur. |
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HTST Pasteurization of Milk |
High Temp Short Time: minimum of 72° for 15 seconds (75° if sugar in product). Milk keeps well under refrigeration. |
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UHT Treatments of Milk
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Ultra-High Tempetraure Treatments:
Sterilization of milk which allows for storage for several months without refrigeration - 140° C for 4 seconds, packed in a presterilized containerie. used for coffee creamers in US |
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Dry Heat (kills by oxidation effects) |
1. Direct Flaming: Sterilization 2. Incineration: Sterilization 3. Hot air oven: Sterilization (common run 170° for about 2 hrs) - dry heat requires longer times because for same temp, it carries less heat. |
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Filtration (separation of bacteria from suspending liquid) |
- passage of a liquid or gas through a screenlike material with pores small enough to retain microbes - can get filters with specific pore sizes, most filters pass viruses -ie. HEPA filters (High-efficiency particulate air) |
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Cold: Low Temperatures (Static) |
- static for most organisms - metabolic rate of most microbes so reduced that they cannot reproduce or synthesize toxins |
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Refrigeration (Static) |
optimum remp is just above freezing (0-7° C) - except for microbes that thrive in cold |
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Freezing (Static) |
optimum temp for home freezer is 0° F or (-17°C) |
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Drying (Dessication): Static |
- static for most organisms - denies cell of moisture needed for growth ie. clothing, bedding and fressing may contain infectious microbes in dried mucus, urine, pus and feces |
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Listeria |
- one important exception of Pathogenic bacteria that can grow in refrigerator temperatures |
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High Pressures (Disinfection) |
- disinfection - alters molecular structures of proteins/carbohydrates results rapid inactivation of vegetative cells. - a treatment that preserves flavors, colors and nutrient values of products |
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Osmotic Pressure (Static) |
- high concentrations of salt or sugars which creates a hypertonic environment that causes water to leave the microbial cell. - denies the cell moisture needed for growth -ie. curing meats/preserving fruits |
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Ionizing Radiation (Sterilization) |
- ionization of water, forms highly reactive hydroxyl radicals that kill organisms by reacting with DNA and damaging them - destruction of DNA X-rays: produced by beam of high voltage electrons Gamma Rays: produced by decaying isotopes - both have great penetration ability |
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Nonionizing Radation (Ulra-Violet Light) |
- damages DNA - optimum wave length: 260 nm - poor penetrating ability - used to disinfect vaccines/air |
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MIcrowaves |
- do not have much direct effect |
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DRAW OUT TABLE 7.5 (pg. 186) |
This is basically the whole fuckign chapter lol wtfcuk. |
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Lyophilization |
- Decreases chemical reactions/changes in proteins - Most effective method for long-term preservation; Process of water removal by a high vacuum at low temperatures |
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tincture |
a solution with an alcohol solvent ie. iodine tincture |
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oligodynamic action |
- the ability of very small amounts of heavy metals to exert antimicrobial activity - ie. silver, copper, zinc, and mercury |
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List five factors related to effective disinfection |
1. kills all pathogens including spores and viruses 2. harmless to human or animal tissues 3. harmless to instruments and matericals (non corrosive/non staining) 4. good penetrating ability 5. works well at cool temperatures 6. nonflammable 7. has cleaning ability 8. has deodorizing ability 9. not inactivated by organic matter 10. good shelf life 11. low cost |
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Contast -cidal vs. -static action of antimicrobial agents |
-cidal: kills microbes at a logarithmic rate ie. cavicide -static: prevents the growth of microbes ie. freezing can prevent growth of bacteria, but if returned to normal temps then it will grow again |
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Disinfectant vs. Antiseptic |
A disinfectant: is used to destroy vegetative pathogens on inanimate objects An antiseptic: is used to destroy vegetative pathogens on living tissue -both are usually chemicals |
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Remember: Gram-Negative bacteria are generally more resistant than Gram-Positive Bacteria to disinfectants and antispects. Prions, endospores of bacteria, mycobacteria and protozoan cysts and oocytes are very resistant. Organic matter (vomit and feces) frequently affectst the actions of chemical control agents, so the environment matters too. |
Gram-negative are more resistant |
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Write/Draw out Table 7.8 for a summary of Chemica lConrol Methods covered in Lecture |
LOL OKAY. |
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Phenol and Phenolics |
phenol = carbolic acid - the first disinfectant/antiseptic, introduced by Joseph Lister 1. Phenol 2. Phenolics 3. Biphenols - disruption of plasma membrane/denaturation of enzymes |
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Biguanides (Chlorhexidine) |
- disruption of plasma membrane - for skin and mucuous membranes (hand soaps and lotions) |
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Halogens (Iodine) |
- Iodine inhibits protein function Iodine: 3 forms 1. Aqueous 2. Tincture 3. Organics |
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Halogens (chlorine) |
- chlorine alters cellular componencts - bleach = sodium hypochlorite 5.25% - used for water treatment |
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Alcohols |
- protein denaturation and dissolves lipids - ethanol (better) - isopropanol (best) - optimum concentration at 70%; higher concentration is less effection, action requires presence of some water - do not kill bacterial spores or most viruses |
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Heavy Metals |
- denaturation of enzymes and proteins - oligodynamic action: Toxic effect of metal ions on microbes - mercury, inactivated by organic matter - silver nitrate - used on infant's eyes to prevent gonorrheal infection - copper, zinc |
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Surface-Active Agents |
1. Soaps and Detergents 2. Acid anionic sanitizers 3. Quaternary ammonium compouds (cationic detergents) - combine cleaning/disinfectant ability = good for gram + bacteria, fungi, protozoa but weak against gram - or spores Surfactants decreases the surface tension of liquids, makes the mwetter and improves penetration and cleaning ability |
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Oxidizing Agents (Peroxygens and Other Forms of OXygen) |
- various chemicals that release free oxygen (0) hydrogen peroxide: H2O2 --> H2O + O - effectively disinfects inanimate objects peracetic acid: effective liquid sporicide and sterilant ozone: O3 --> O2 + O - Benzoyl peroxide - used for Deep Wounds |
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Dyes |
Crystal Violet - more effective against Gram + than Gram - (used to treat candida albicans) |
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Chemical Food Preservatives |
1. Organic Acids widely used to control molds and bacteria in food or cosmetics 2. Nitrates prevents growth of Clostridium botulinum in food; imparts red color. |
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Aldehydes |
- Protein denaturation, verry effective antimicrobial for disinfecting medical equipment. |
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Chemical Sterilization |
- Inhibits vital cellular functions (sterilization of materials that would be damaged by heat) |
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Evaluation of Disinfectnats |
Disk-Diffusion Method 1. Inoculate agar plate with pathogen 2. Place paper discs dipped in different disinfectants on surface of agar 3. Incubate 4. Compare zones of inhibition |