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24 Cards in this Set
- Front
- Back
Sterilization
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A process that destroys or removes all viable microorganisms, including viruses
Reserved for inanimate objects, such as surgical instruments, syringes, and commercially packaged foods An object is either sterile or it is not sterile, there is no in between |
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Bactericide
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A chemical that destroys bacteria, except for those in the endospore stage
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Bacteriostatic
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Agents that prevent the growth of bacteria on tissues or on objects in the environment
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Germicide
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Any chemical agent that kills pathogenic microorganisms
Can be used on both inanimate materials and living tissue CANNOT kill resistant microbial cells |
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Disinfection
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The use of a physical process or a chemical agent to destroy vegetative pathogens, but not bacterial endospores
Process can remove the harmful products of microorganisms Toxic to living tissue in the concentration required to be effective, therefore used on inanimate objects |
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Asepsis
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Any practice that prevents the entry of infectious agents into sterile tissues thus preventing infection
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Antiseptic
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Chemical agents that are applied directly to exposed body surfaces, wounds, and surgical incisions to inhibit or destroy vegetative pathogens
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Mode of Action
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An antimicrobial (disinfectants and antiseptics agent's adverse effect on cells
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Sanitization
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Refers to any cleansing technique that removes debris, microorganisms, and toxins, and in this way reduces the potential for infection and spoilage
Soaps and detergents are the most commonly employed sanitizers Is often preferable to sterilization |
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Factors that affect Microbial Death
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1. the number of microbes present, the high load of contaminants requires more time to destroy
2. the nature of the microorganisms in the population 3. the temperature and pH of the environment 4. the concentration (intensity/dosage) of the agent 5. the mode of the agent, how does it kill the microorganism |
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Four Modes of Actions
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1. Effect on cell wall- damage wall by blocking its synthesis, digesting it, or breaking down its surface leaving cell fragile
2. Effect on cell membrane- if membrane is destroyed cell loses its selective permeability and can neither prevent the loss of vital molecules nor bar the entry of damaging chemicals 3. Effects on protein and nucleic acids synthesis- block protein synthesis inhibiting metabolism and growth or block DNA replication 4. Effects on protein function- denature cells proteins through pH, temperature or block active site of enzymes |
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Physical Control: Moist Heat
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Can establish thermal death time (how long it takes to kill the organism) and sterilizes and controls faster than dry heat
Methods: - non-pressurized steam - boiling water - pasteurization - steam under pressure (will control endospores), autoclave is most effective |
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Physical Control: Dry Heat
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Incineration
- cremation - flaming loop in lab |
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Physical Control: Cold and Desiccation
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Cold temperatures are biostatic- do not kill microorganism, just slows down the growth of the culture
Desiccation- dehydrating cells lyophilization- freezing and dehydrating microorganism |
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Physical Control: Radiation
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Causes the breakdown of DNA and structure of microorganism
Ionizing- gamma, x, and cathode rays Non ionizing- UV rays |
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Physical Control: Filtration
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Mechanical removal of microorganisms
ex) water system filtration |
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Chemical Control Agents: Halogens
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- Chlorine- gaseous and liquid state disinfect water
EX) hypochlorite: bleach EX) Chloramines - Iodine- topical antiseptic, treatment for burns, and disinfection of inanimate objects |
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Chemical Control Agents: Phenols
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- Phenol: general disinfections
- Bisphenols: Lysol - Chlorhexidine: mild low toxicity, hand scrubbing, surgical incision site, and wound degermer (only antiseptic phenol) |
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Chemical Control Agents: Alcohols
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70% alcohol is most effective
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Chemical Control Agents: Hydrogen Peroxide
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Acts as both an antiseptic and a disinfectant depending upon its concentration
3% and below= antiseptic 4% and above= disinfectant will kill normal flora in human body and can breakdown tissue, therefore not heavily used as antiseptic |
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Chemical Control Agents: Heavy Metals
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Copper, Gold, and Silver
All metals, esp heavy metals, have an anti microbial property |
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Chemical Control Agents: Aldehydes
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Formaldehyde, 1% solution (formalin) can be used in ponds to control algae without killing animals
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Chemical Control Agents: Dyes
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Eosin Methylene Blue (EMB) will control the growth of gram positive organisms
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Chemical Control Agents: Acids and Alkalis
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Adjusts the pH therefore killing organism
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