Chapter 11 Exam Test – Flashcards
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| 1. Sterilization: |
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| 1. Sterilization: the destruction of all microbial life including viruses and endospores |
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| 2. Disinfection: |
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| destroys most microbial life, reducing contamination on inanimate surfaces (not endospores) |
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| 3. Antisepsis: |
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| destroys most microbial life, reducing contamination on a living surface (not endospores) |
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| 4. Decontamination: A. Sanitization B. Degermination |
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| the mechanical removal of most microbes from an animate or inanimate surface a) Sanitization: any cleaning technique that mechanically removes microorganisms to reduce contamination to safe levels b) Degermation: reduces the number of microbes on the human skin (mechanical) |
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| 5. Asepsis: |
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| any practice that prevents the entry of infectious agents into sterile tissues |
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| 6. Disinfectant: |
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| a chemical agent used to destroy a vegetative pathogens |
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| 7. Sterilant: |
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| Chemical used in sterilization to kill all microorganisms |
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| 8. Antiseptics: |
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| applied directly to exposed body surfaces to destroy or inhibit vegetative pathogens |
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| 9. Sanitizer: |
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| compound such as soap or detergents that sanitizes |
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| 10. Sepsis: |
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| the growth of micro-organisms in the blood and other tissues |
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| Microbial control methods (Physical Agents) |
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| A. Heat- DRY 1. Incineration= Sterilization 2. Dry Oven= Sterilization MOIST 1. Steam under pressure= sterilization 2. Boiling water, hot water, pasteurization= Disinfection B. Radiation- 1. Ionizing- X-ray, cathode, gamma= Sterilization 2. Nonionizing- UV= Disinfection |
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| Microbial control methods (Chemical Agents) |
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| 1. Gases= Sterilization and Disinfection 2. Liquids- Animate=Antisepsis Inanimate= Disinfection and Sterilization |
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| Microbial control methods Mechanical Removal |
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| Filtration 1. Air= Decontamination 2. Liquids= Decontamination |
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| Know difference between –static and –cide |
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| static - to stand still cide- to kill |
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| – Bactericide: |
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| chemical that destroys bacteria (not endospores) |
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| – Fungicide: |
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| a chemical that can kill fungal spores, hyphae, and yeasts |
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| – Virucide: |
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| a chemical that inactivates viruses – |
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| Sporicide: |
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| can destroy bacterial endospores |
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| – Germicide |
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| and microbicide: chemical agents that kill microorganisms |
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| – Bacteristatic: |
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| prevent the growth of bacteria |
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| – Fungistatic: |
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| inhibit fungal growth |
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| – Microbiostatic: |
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| materials used to control microorganisms in the body, for example |
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| Know the factors you consider when choosing your form of control |
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| • Does the application require sterilization, or is disinfection adequate• Is the item to be reused or permanently discarded• If it will be reused, can it withstand heat, pressure, radiation, or chemicals• Is the control method suitable for a given application• Will the agent penetrate to the necessary extent• Is the method cost- and labor-efficient, and is it safe? |
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| Know what factors influence the treatment’s effectiveness |
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| • The number of microorganisms • The nature of the microorganisms in the population • The temperature and pH of the environment • The concentration of the agent • The mode of action of the agent • The presence of solvents, interfering organic matter, and inhibitors |
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| Know how you denature a protein |
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| By increasing heat and/or changing the PH |
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| Which is more affective moist or dry heat |
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| Moist Heat because it penetrates deeper |
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| What optimal pressure and steam combo and whats the name of the machine |
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| • Steam under pressure – Pressure raises the temperature of steam by raising boiling point – Autoclave is used – Most efficient pressure-temperature combination for sterilization: 15 psi which yields 121°C |
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| • Thermal death time (TDT) |
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| : the shortest length of time required to kill all test microbes at a specified temperature |
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| • Thermal death point (TDP): |
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| the lowest temperature required to kill all microbes in a sample in 10 minutes |
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| Know the disadvantage of tyndallization and why you would use it |
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| • You would use it to sterilize glass that is not pressure treated, such as those made for chemistry, the disadvantage is the amount of time (3 days) it takes to do it. Expose to free-flowing steam for 30-60 minutes, incubate for 23-24 hours, treat again; repeat for 3 days in a row. |
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| Know what pasteurization is used for and the two methods |
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| • Used to disinfect beverages • Heat is applied to liquids to kill potential pathogens and spoilage, while retaining the liquid’s flavor and food value • Special heat exchangers – Flash method: expose to 71.6°C for 15 seconds – Batch method: expose to 63°C to 66°C for 30 minutes • Does not kill endospores or thermoduric microbes |
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| Know the two forms of dry heat and what they are used for |
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| Incineration- Sterilization • Ignites and reduces microbes to ashes and gas • Common practice in microbiology lab- incineration on inoculating loops and needles using a Bunsen burner • Can also use tabletop infrared incinerators DRY OVEN- Sterilization • Usually an electric oven • Coils radiate heat within an enclosed compartment • Exposure to 150°C to 180°C for 2 to 4 hours • Used for heat-resistant items that do not sterilize well with moist heat |
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| • Desiccation: |
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| dehydration of vegetative cells when directly exposed to normal room air |
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| • Lyophilization: |
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| a combination of freezing and drying; used to preserve microorganisms and other cells in a viable state for many years |
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| what happens to a culture in the refrigerator |
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| • slow growth of cultures and microbes in food during processing and storage • Cold does not kill most microbes; freezing can actually preserve cultures |
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| Know two forms of radiation, unit of measurement, how each works, and what each is used for |
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| • Ionizing radiation: if the radiation ejects orbital electrons from an atom causing ions to form; used for medical supplies and greys • Nonionizing radiation: excites atoms by raising them to a higher energy state but does not ionize them; wavelength in nm, hospital room, dental office, food prep area, schools. |
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| Know the forms of ionizing radiation and which is best- |
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| best---GAMMA! • Cold sterilization • Dosage of radiation- measured in Grays • Exposure ranges from 5 to 50 kiloGrays • Gamma rays, most penetrating; X rays, intermediate; cathode rays, least penetrating |
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| Define tincture |
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| Solutions dissolved in pure alcohol or water-alcohol mixtures |
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| Know what factors to consider when choosing your chemical |
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| • Rapid action even in low concentrations • Solubility in water or alcohol and long-term stability • Broad-spectrum microbicidal action without being toxic to human and animal tissues • Penetration of inanimate surfaces to sustain a cumulative or persistent action • Resistance to becoming inactivated by organic matter • Noncorrosive or nonstaining properties • Sanitizing and deodorizing properties • Affordability and ready availability |
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| Know what factors influence the chemical you chose |
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| • Nature of microorganisms being treated • Nature of the material being treated • Degree of contamination • Time of exposure • Strength and chemical action of the germicide |
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| Sterilant |
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| – Chlorine compounds: liquid and gaseous chlorine, hypochlorites, chloramines |
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| Iodine |
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| – Iodine compounds: free iodine and iodophors • Topical antiseptic- free iodine • Disinfectant- idophors |
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| Define phenol coefficient |
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| Compares a chemical’s antimicrobic properties to those of phenol—high concentrations: cellular poisons, --lower concentrations: inactive certain critical enzyme systems |
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| Know which two forms of alcohol to use, know how it works against the microbe at the 3 concentrations |
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| • Only ethyl and isopropyl alcohols are suitable for microbial control- Sterilant • Mechanism of action depends in part upon its concentration – 50% and higher dissolve membrane lipids, disrupt cell surface tension, and compromise membrane integrity – 50% to 90% denatures proteins through coagulation; but higher concentration does not increase microbicidal activity – 100% (absolute alcohol) dehydrates cells and inhibits their growth • Does not destroy bacterial spores at room temperature but can destroy resistant vegetative forms • More effective in inactivating enveloped viruses than nonenveloped viruses because it breaks down the envelop. |
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| Know how hydrogen peroxide works and if disinfectant or sterilant |
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| • Germicidal effects are due to the direct and indirect actions of oxygen • Oxygen forms hydroxyl free radicals which are highly toxic and reactive to cells • Bactericidal, virucidal, and fungicidal- 3% antiseptic, disinfectant • In higher concentrations is sporicidal- Sterilant |
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| Know how surfactants, detergents, work |
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| Chemicals with Surface Action: Detergents- Disinfectant • Act like sufactants • Anionic detergents have limited microbicidal power • Cationic detergents are more effective because the positively charged end binds well with the predominantly negatively charged bacterial surface proteins • Soaps are weak microbicides but gain germicidal value when mixed with agents such as chlorhexidine or iodine |
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| Know how heavy metals work |
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| HEAVY METALS • Hg, Ag, Au, Cu, As, and Zn have been used • Only Hg and Ag still have significance as germicides • Oligodynamic action: having antimicrobial effects in exceedingly small amounts • Bind onto functional groups of proteins and inactivating them • Drawbacks to using metals in microbial control: • Can be very toxic to humans • Often cause allergic reactions • Large quantities of biological fluids and wastes neutralize their actions • Microbes can develop resistance to them |
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| Know the two aldehydes- sterilant |
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| Glutaraldehyde and formaldehyde (formalin- aqueous solution) |
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| Know the 2 aniline dyes and what they inhibit |
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| crystal violet and malachite green Inhibit- gram-positive species of bacteria and various fungi |
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| Know disadvantages of dyes , heavy metals, acids, and alkalis |
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| • Very low or high pH can destroy or inhibit microbial cells • Acid Alkolis- Limited in applications due to their corrosive, caustic, and hazardous nature • Heavy metals- microbes can develop resistance, toxic, cause allergic reactions, easily divided • Dyes- stain and narrow spectrum |
