Ch. 11 – Microbiology – Flashcards
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| What is sterilization? |
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| The destruction of all microbial life. |
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| What is disinfection? |
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| Destroys MOST microbial life, reducing contamination on inanimate surfaces. |
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| What is antisepsis? |
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| Destroys MOST microbial life, reducing contamination on a living surface. |
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| What is decontamination? |
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| The mechanical removal of most microbes from an animate or inanimate surface. |
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| What are the primary targets of microbial control? |
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| the microorganisms that can cause infection or spoilage that are constantly present in the external environment. |
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| What microorganisms have the highest resistance to forms of control? |
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| Prions and bacterial endospores. |
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| What microorganisms have moderate resistance to forms of control? |
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| Protozoan cysts, some fungal spores, naked viruses, and some hearty bacteria like M.Tuberculosis, S.Aureus and Psuedomonas. |
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| What microorganisms have the lowest resistance to forms of control? |
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| Most vegetative bacterial cells, most fungal spores/hyphae, enveloped viruses, yeasts and protozoan trophozoites. |
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| What are the methods of microbial control? |
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| 1.)Sterilization 2.)Disinfection 3.)Antisepsis 4.)Sanitization 5.)Degermination |
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| What does sterilization do? What surfaces is it used on? What accompanies it? |
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| Removes all viable microorganisms including viruses and spores. Inanimate. Usually heat but chemicals can be used as well. |
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| What does disinfection do? What surfaces is it used on? What accompanies it? |
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| The use of a physical process or chemical agent (disinfectant) to destroy vegetative pathogens and most viruses. DOES NOT DESTROY BACTERIAL ENDOSPORES AND SOME VIRUSES. Removes toxins. Used on inanimate surfaces. |
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| What does Sanitization do? |
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| Any cleansing technique that mechanically removes microorganisms to reduce contamination to safe levels. Ex: washing dishes or clothes. |
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| What is degermation? How does it work? |
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| Reduces the numbers of microbes on HUMAN SKIN. Works by removing oils and microbes on the outer layer of the skin through physical/chemical or both. Ex: hand washing and surgical scrubbing. |
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| What does CIDE mean? |
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| To kill. DOES NOT NECESSARILY RESULT IN STERILIZATION. |
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| What is a bactericide? |
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| chemical that destroys bacteria NOT endospores |
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| What is a fungicide? |
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| Chemical that kills fungal spores, hyphae, and yeasts. |
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| What is a virucide? |
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| A chemical that inactivates viruses. |
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| What is a sporicide? |
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| Can destroy bacterial endospores. |
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| What is a germicide/microbicide? |
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| Chemical agents that kill a variety of microorganisms. |
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| What does statis/static mean? |
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| To stand still. |
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| What is bacteristatic? |
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| Prevent the growth of bacteria. |
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| What is fungistatic? |
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| inhibit fungal growth. |
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| What is a microbistatic? |
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| Materials used to control microorganisms in the body such as antiseptics. |
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| What is microbial death? |
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| When cell structures become dysfunctional and the cell becomes irreversibly damaged OR a cell can no longer reproduce under ideal environmental conditions. |
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| What are the factors that influence action of antimicrobial agents? |
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| 1.)The number of microorganisms 2.)The nature of the microorganism 3.)The temp and pH of environment 4.)The concentration of the agent 5.)The mode of action of the agent 6.)The presence of solvents, interfering organic matter and inhibitors. |
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| What are the 4 ways agents work? |
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| 1.)Affect the cell wall 2.)Affect the cell membrane 3.)Affect protein synthesis 4.)Affect protein function |
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| How do agents affect the cell wall? |
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| By blocking its synthesis, digesting it or breaking it down. Once gone, the cell is easily lysed. |
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| What is an example of an agent that effects a cell wall? |
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| Penicillin, cephalosporins, vancomyocin, detergents, and alcohol. |
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| How do agents affect the cell membrane? |
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| They disrupt the normal transport of materials in/out of the cell or allow the free flow of substances in/out of the cell. |
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| What is an example of an agent that effects the cell membrane? |
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| Surfactants - detergents that easily open holes in the membrane |
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| How do agents affect protein synthesis? |
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| They disrupt DNA transcription or replication OR disruption of the translation in the ribosomes. |
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| What is an example of the disruption of DNA transcription/replication? |
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| Ciprofloxacin, sulfonamides, and radiation (gamma, UV and X) |
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| What is an example of the disruption of the translation in the ribosomes? |
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| Streptomycin, tetracycline, chloramphenicol, and erythromycin. |
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| How do agents effect protein fucntion? |
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| Generally work by altering protein's natural structure (conformation). |
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| What is denaturation? |
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| Involves breaking the bonds within the protein to disrupt its conformation. |
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| What is coagulation? |
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| Aggregation of proteins resulting in a non-functioning mass. |
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| What are the 4 methods of physical control? |
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| 1.)Heat 2.)Cold/Desiccation 3.)Radiation 4.)Filtration |
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| Generally, ______ temperatures are microbicidal and ______ temperatures are microbistatic. |
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| higher/lower |
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| What are the common methods of moist heat control? |
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| 1.)Pressurized Steam 2.)Non-pressurized Steam 3.)Pasteurization 4.)Boiling water 5.)Dry heat |
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| What is pressurized steam? What does it destroy? What is it used on? |
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| Increasing the pressure of steam allows for higher temps and better microbe killing. It destroys vegetative cells, spores and viruses. Sterilizes heat-resistant materials and any material that will be discarded. |
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| What is pressurized steam NOT effective against? What is an example of a pressurized steam method? |
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| Not effective in sterilizing substances that repel or absorb moisture (waxes, oils, powders.) Autoclave is a commercial device used for steam-heat sterilization. Average setting = 15 psi 121 celcius for 15 minutes. |
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| What is non-pressurized steam? What does it kill? What is it ineffective against? |
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| Intermittent sterilization. Destroys vegetative cells and viruses but NOT spores. Used to sterilize heat sensitive culture media. Inneffective against objects that don't allow microbial growth but can disinfect them. |
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| How does non-pressurized steam work? |
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| Exposed to free-flowing steam for 30-60 minutes, incubate for 23-24 hours, treat again and repeat for 3 days in a row. |
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| What is pasteurization? |
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| Technique in which heat is applied to liquids to kill potential agents of infection and spoilage while maintaining flavor and food value. |
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| What does pasteurization sterilize? |
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| Does not STERILIZE the liquid as spores, thermoduric and thermophilic organisms still remain. |
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| What is flash pasteurization? |
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| 71.6 celcius for 15 seconds - common in Asia |
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| What is Batch pasteurization? |
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| 63-66 celcius for 30 minutes - common in USA |
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| What is Ultrahigh-temperature pasteurization? |
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| 134 celcius for 1-2 seconds. Allows milk to be stored for long periods at room temperature aka coffee creamer. |
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| What is the goal of pasteurization? |
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| To prevent the transmission of milk-borne diseases from infected cows and milk handlers. |
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| Does pasteurization kill ALL microbes? |
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| no |
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| What does boiling water do? How does it work? What is its downside? |
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| For DISINFECTION NOT STERILIZATION. Expose materials to boiling water for 30 minutes. After 10, all non-spore forming pathogens and most viruses. Decontaminates suspect drinking water. Biggest downside = recontamination. |
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| What are the 2 methods of dry heat sterilization? |
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| Incineration and Dry Oven |
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| What does incineration do? |
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| Ignites and reduces microbes to ashes and gas. Common practice in microbiology lab - flaming the loop. Hospitals use it to eliminate infectuous waste products. |
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| What does dry oven do? |
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| Electric coils radiate heat within an enclosed compartment. Sterilization occurs at 150-180 celcius for 2-4 hours. Is used on heat-resistant items that do not sterilize well with moist heat. |
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| What does refridgeration and freezing do? |
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| Designed to SLOW microbial growth. Common in food processing and storage. Not considered a viable method of sterilization or disinfection. |
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| What does dessication do? |
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| Drying. Inhibits growth by removing water. Inhibits the spread of most pathogens but not all of them. Not considered a viable method of sterilization or disinfection. |
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| What is lyophilization? |
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| Mixture of freezing and drying. Used to preserve microbes and other cells for long periods of time. |
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| What is radiation? |
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| Energy emitted from atomic activities and dispersed at high velocity through matter or space. |
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| What are the 2 categories of radiation? |
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| Ionizing and Non Ionizing |
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| What is ionizing radiation? |
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| Excites the electrons to the point that they are ejected from the molecule entirely causing the formation of ions. DNA is the most sensitive. |
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| Ionizing radiation causes ______ _______ ______ in organelles and the production of toxins. |
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| lethal chemical changes. |
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| What is ionizing radiation used in? |
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| Sterilization of commercial food products. |
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| What are the potential problems with ionizing radiation? |
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| Potential change in taste and nutritional value, and introducing undesirable chemical rxns. Causes potential danger to operators and possible damage to materials. |
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| What is ionizing radiation the preferred method of sterilization for? |
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| Drugs and tissues by hospitals. |
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| What are some examples of ionizing radiation? |
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| Gamma rays, x rays, cathode rays |
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| What is non-ionizing radiation? |
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| Excites electrons causing them to jump orbitals but don't leave the molecule. Leads to abnormal linkages and bonding. DNA is very succeptible. Leads to Thymine dimers. |
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| What is non-ionizing radiation usually used for? |
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| Disinfecting air. Commonly seen in lights in hospitals, operating rooms, schools, food prep areas, and dental offices. Can treat liquids. |
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| Does non-ionizing radiation pass easily through solids? What is its threat? |
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| No but can be used in some applications. Can be damaging to human skin. |
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| What is filtration effective in removing? How does it work? |
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| Microbes from the air and liquids. Fluid strained through a filter with openings large enough for fluid but too small for microorganisms. |
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| When is filtration used? |
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| Prepare liquids that can't withstand heat such as serum, blood products, vaccines, IV fluids, and enzymes. Can decontaminate beverages without altering their taste. Water purification. Can remove airborne contaminates. |
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| What are sounds waves used for? |
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| Disrupt cell structure. Sonicator. Gram negative bacteria are most susceptible. NOT A RELIABLE SOURCE OF DISINFECTION/STERILIZATION BY ITSELF |
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| What is osmotic pressure used for? |
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| Salt concentration. Involves the use of salt to create a hypertonic environment. Results in water leaving the cell which inhibits cellular processes. |
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| What are the chemical agents of microbial control? |
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| 1.)Halogens 2.)Phenols/Derivatives 3.)Alcohols 4.)Oxidizing agents 5.)Surfactants/Detergents 6.)Heavy Metal Compounds 7.)Aldehydes 8.)Gaseous Sterilants and Disinfectants |
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| How do the halogens work? What are some examples? DISINFECTANT |
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| They generally disrupt microbial enzyme function. They are effective against vegetative cells and some spores. Ex: Household bleach and betadine |
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| How do the phenols work? What are some examples? DISINFECTANT |
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| Effective against vegetative cells but not spores. They denature proteins and disrupt cell membranes. Have nasty odor and bad side effects. Ex: Orthophenylphenol (lysol), hexylresocrinol (throat lozenges), hexochlorophene (Phisoderm) |
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| How do alcohols work? What are some examples? DISINFECTANT |
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| Effective against vegetative cells but NOT spores. Mostly inactivation of enveloped viruses than nonenveloped viruses. Work by denaturing proteins and disrupting cell walls and membranes. Disadvantage - evaporate quickly. Isopropanol and ethanol commonly used in 70-95% mixtures. 100% alcohol dehydrates cells and inhibits their growht. |
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| How do oxidizing agents work? What are some examples? DISINFECTANT. |
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| Bactericidal, virucidal, fungicidal and sporicidal in higher concentrations. Effective against anaerobic organisms. Used to treat drinking water and eliminate spores on surfaces. Oxidize enzymes and shuts down microbes metabolism. Ex: peroxide, ozone, paracetic acid. |
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| How do surfactants/detergents work? What are some examples? DISINFECTANT |
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| Work against vegetative cells but NOT spores. Work by disrupting the cell membrane structure. Ex: soaps, detergents, mouthwash. |
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| How do heavy metal compounds work? What are some examples? |
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| All work differently. Most are no longer used. Copper - algae growth in water. Zinc/Mercury - fungal growth in paint Silver - oral ulcers. opthalmic gonorrhea. In plastic and steel to control microbial growth. Germicidal ointments. Catheters to prevent UTI's. Mercury - Antiseptic |
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| How do aldehydes work? What are some examples? STERILIZERS |
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| Denature proteins and inactivate nucleic acids. Glutaraldehyde - cleaning lensed instruments and some respiratory equipment. Carcinogenic. Formaldehyde - vapor sterilizes laboratories. |
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| How do gaseous sterilizers and disinfectants work? What are some examples? |
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| Ethylene Oxide Gas - effective against all microbes. Reacting with proteins. Useful in sterilizing fabrics, implantable objects and any heat or moisture sensitive items. Exposure time = 3-12 hours for full sterilization. GAS IS TOXIC, EXPLOSIVE, POTENTIALLY CARCINOGENIC. |
