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Microbio ch13
Question | Answer |
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Define: fomite, (do not have to know specifics) | Item used by humans that can harbor microbes and aid transmission |
BSL | Biological Safety Levels: 4 categories that rank microbes from the lowest risk to the highest risk |
sterilization | Destruction of all microbial life (includes viruses) |
disinfection | Destroys pathogens on surfaces/ Vegetative pathogens/ Physical or chemical methods |
sanitization | Lower microbial counts to safe levels/ usually in commercial establishments/ This is done by high temperature washing & dipping in a disinfectant |
Understand ANTISEPSIS and degerming. | Removing microbes from living tissue (antiseptics used for this, usually with chemicals) |
Understand antisepsis and DEGERMING. | Mechanical removal, not killing, of microbes from a limited area/ Swabbing skin with alcohol before injection |
What are critical items and which protocol is used for each? | Used inside the body or penetrate tissues/blood// Must be sterile |
What are semi-critical items and which protocol is used for each? | Contact mucous membranes of unbroken skin/ High level disinfection, no sterilization |
What are non-critical items and which protocol is used for each? | Contact but do not penetrate skin/ Clean |
Understand the four factors to consider when choosing a method of controlling microbial growth. | Initial size of the microbial population/ Time of exposure/ Environment/ Characteristics of specific microbes |
Understand heat methods, including dry heat | Kills by oxidation effects: flaming, incineration, hot-air sterilization |
Understand heat methods, including, moist heat/autoclaves | Produces steam under pressure so temps are greater than that of boiling water/ Standard: 15PSI (121ºC) for 15 min/ Tabletop & industrial versions/ Sterilizes |
Understand heat methods including, pasteurization. | Eliminates pathogens and lower microbial numbers to prolong life of product/ Ex: Classical 63ºC,30min//HTST 72ºC,17min//UHT Sterilizes milk |
Understand refrigeration | Effect how temps are depending on kind of bacteria or microbe/ Psychrophiles continue to grow/ Bacteria may go dormant/ Some bacteria preserved by freezing, others killed (EX: Eukaryotic) |
Understand pressure | High pressure kills microbes/ Pascalization/ Hyperbaric oxygen therapy/ Desiccation/ Lyophilization |
What two types of radiation can be used to control microbial growth? | Ionizing & non-ionizing radiation |
Understand filtration. | HEPA filters remove microbes, endospores, and viruses Membrane filtration removes bacteria from liquids (that cannot be autoclaved) |
Know the examples of chemical methods of microbial control: phenols and phenolics, pt1 | First used in surgery (Lister)/ Lipid soluble/ Denature proteins/ used in throat sprays/stable/ Disinfectants for surfaces |
Know the examples of chemical methods of microbial control: phenols and phenolics, pt2 | Cresols: from coal tar, in Lysol/ Bisphenols: Hexachlorophene is good for Gram + bacteria & Triclosan- in soaps, toothpastes, sheets, etc. Good against Gram + and - bacteria |
Know the examples of chemical methods of microbial control: heavy metals, | Oligodynamic action-Very small amounts exert antimicrobial activity/ Denature proteins/ AG,Hg,Cu,Zn |
Know the examples of chemical methods of microbial control: heavy metals, pt2 | Silver nitrate Ag used to prevent ophthalmia neonatorum/ Mercuric Chloride Hg prevents mildew in paint/ Copper sulfate Cu is an algicide/ Zinc chloride Zn is found in mouthwash |
Know the examples of chemical methods of microbial control: iodine | Tincture: solution in aqueous alcohol/ Iodophor: combines with organic molecules(betadine)/ Oxidizes cellular components |
Know the examples of chemical methods of microbial control: chlorine | Oxidizing agents; shut down cellular enzyme systems/ Chlorine gas/ bleach/ chloramine |
Know the examples of chemical methods of microbial control: alcohols | Most common: ethanol, isopropanol/ Disrupts membranes/ kill bacteria and fungi, but not endospores or non-enveloped viruses/ Degerming |
Know the examples of chemical methods of microbial control: surfactants | Includes soaps and surfactants/ Lower the surface tension of water/ Create emulsions/ Degerming |
Know the examples of chemical methods of microbial control: quats | Cationic detergents/ Disrupt membranes/ Stable, nontoxic, inexpensive, colorless, odorless, tasteless/ Bactericidal/ no not affect mycobacteria or endospores |
Know the examples of chemical methods of microbial control: bisbiguanides | Causes gross permeability changes to cell membrane/ Used on skin and mucous membranes/ Combined with detergents and alcohols/ Affected: vegetative bact, yeast, enveloped viruses/ Unaffected: mycobacteria, endospores, non-enveloped viruses |
Know the examples of chemical methods of microbial control: alkylating agents | Inactive enzymes and nucleic acids/ Formaldehyde/ Glutaraldehyde/ o-phthalaldehyde/ Ethylene dioxide/ B-Propionolactone |
Know the examples of chemical methods of microbial control: peroxygens | Oxidizing agents, highly reactive: oxidize cellular components of microbes/ Ozone/ Hydrogen peroxide/ Benzoyl peroxide/ Peracetic acid |
Know the examples of chemical methods of microbial control: supercritical fluids. | Compressed state/ CO2 at 10x atmospheric pressure/ Sterilizes/ Enters cell, forms carbonic acid, lowers pH (Works with vegetative cells & endospores together with peracetic acid)/ Food, medical devices, tissues |
Understand the disk-diffusion method, e-test, use-dilution test, and in-use test. | spread a place with bacteria/ place filter disks soaked in diff disinfectants on top/ incubate/ determine lawn grows/ extent |
Understand the disk-diffusion method, e-test, use-dilution test, and in-use test. | Provides a minimum inhibitory concentration (MIC) |
Understand the disk-diffusion method, e-test, use-dilution test, and in-use test. | Metal cylinders dipped in broth cultures of test bacteria and dried/ Contaminated cylinders are exposed to disinfectant for desired times/ Cylinders dropped back in broth/ Growth or no growth recorded/ kills or not |
Understand the disk-diffusion method, e-test, use-dilution test, and in-use test. | To check if disinfectant is contaminated/ Disinfectant + inactivator/ If growth is observed, the disinfectant was contaminated |
Understand hypertonic environments. | Solute concentration is higher than that inside the cell. Water flows out of cell and into the surrounding solution |