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Chapter 9
Exam 3
37
Microbiology
Undergraduate 3
11/11/2009

Additional Microbiology Flashcards

 


 

Cards

Term
Sterilization
Definition
Removal or destruction of all harmful microbes.
Term
Aseptic
Definition
Eliminates pathogens
Term
Disinfection
Definition
Use of physical or chemical agents to remove orgs from inanimate or nonliving objects (disinfectants)
Term
Antisepsis
Definition
Removal of orgs from living tissues (ex: alcohol)
Term
Degerming
Definition
Removal of microbes by scrubbing
Term
Sanitation
Definition
Disinfecting public places and utensils by reducing # of pathogens to safe levels (steam, hot water, scrubbing, etc.)
Term
Pasteurization
Definition
Use of heat to kill pathogens and reduce spoilage microbes in food and beverages. (milk, fruit juices, wine, beer)
Term
-static vs. -cidal agents
Definition
-static inhibit microbes
-cidal kill them
Term
Factors Affecting Microbial Control
Definition
- nature of sites to be treated.
- susceptibility of microbes
- environmental conditions
Term
Methods for Evaluating Disinfectants and Antiseptics
Definition
1. Phenol Coefficient
2. Use-Dilution
3. Disk-Diffusion Method (Kirby-Bauer)
4. In-Use Test
Term
Phenol Coefficient Test
Definition
Divide amount of agent that kills by Amount of phenol that kills
Term
Use-Dilution Test
Definition
Standard - dip metal cylinders into broth cultures 1 min. Immerse into various dilutions of disinfectant for 10 min, rinse, and add to sterile broth and incubate 48 hrs then look for growth
Term
Disk-Diffusion Method
Definition
Used in Lab - Kirby-Bauer method - Soak sterile paper disk in agent, place on swabbed agar plate, compare zones of inhibition. Must compare diffusion constants!
Term
In-Use Test
Definition
Swabs taken from objects before and after disinfection then placed onto growth media to determine effectiveness.
Term
Physical Methods of Microbial Control
Definition
1. Heat
2. Refrigeration and Freezing
3. Dessication and Lyophilization
4. Filtration
5. Radiation
Term
Heat-related Methods
Definition
Moist Heat - Boiling (everything but endospores) Autoclaving - 15 psi for 15 min 121 *C. Pasteurization - Batch (30 min 63*C), Flash (15s 72*C) Ultrahigh (134C for 1s). Ultrahigh Temp - 140C for 1s then cooled
Dry Heat - Powders 171C 1hr 160c 2hr
Term
Refrigeration and Freezing
Definition
Refrigeration slows metabolism and growth 0-7C Psychrophiles
Freezing Ice crystals puncture cell membrane - slow is better (-30 to -80C storage of microbes with glycerol)
Term
Dessication
Definition
(drying) remove water to stop metabolism (ex: jerky)
Term
Lyophilization
Definition
Freeze drying - freezes then uses vacuum to remove water
Term
Filtration
Definition
passage of fluid through membrane with small pores
Term
Osmotic Pressure
Definition
High concentration of salt/sugar inhibit growth by creating hypertonic solutions and causing water to leave cells. Molds aren't inhibitied - spores!
Term
Ionizing Radiation
Definition
beams, rays, cause electrons to be ejected from atoms, disrupting H bonding, oxidizing double bonds, creating hydroxl ions. DNA easily damaged leading to mutations.
Term
Non-ionizing Radiation
Definition
excite electrons and cause to chemical bonds to be formed, damaging proteins and NA's. UV light-260nm not very penetrating-thymine dimers block transcription and DNA replication.
Term
Chemical Methods of Microbial Control
Definition
Used more- act on proteins, membranes or DNA. Effects vary with temp, time of exposure, concentration, freshness, amnt of organic matter present.
Term
Phenol
Definition
Chemical - denature proteins and disrupt cell membranes, effective in presence of organic matter (advantage). Disadvantages: odor and side effects
Term
Alcohols
Definition
everything but spores. isopropanol and ethanol common. Combined with other chem - tinctures. Most effective with water-Both polar and nonpolar effected. No mess but doesn't stay on long enough.
Term
Halogens
Definition
I, Cl, Br. Used alone or combined. Organic/inorganic forms are used. I-releases slowly, non-staining, non-irritating. Cl-Treat water. May be gas. Can produce carcinogens in water. Br-Used in hot tubs slow evaporate, protects from herpes.
Term
Oxidizing Agents
Definition
Anaerobes. Damage DNA. h2o2- inanimate objects. neutralized by catalase from damaged skin cells. Chems overcome. O-zone - exposing 02 to electricity, expensive. Peracetic Acid - Sporocide, sterilize med. equipment
Term
Surfactants
Definition
"surface active agents" - loosens molecules. Soaps - break up oils. Detergents- + charged, "quats"-quaternary Ammonium compound, Mouthwashes, disrupt cell membrane, not effective against envelope viruses or spores.
Term
Heavy metals
Definition
As, Zn, Hg, Ag, Cu. Denatures proteins. Silver-surgical dressings, burn creams, catheters. Copper-Interferes with Chlorophyll synthesis (algae), pathogens don't have chlorophyll tho!!
Term
Zinc
Definition
Control mildew in paint
Term
Mercury
Definition
Used to control mildew in paint - mercurochrome, merthiolate
Term
Aldehydes
Definition
end in "-CHO" denature proteins, Gluteraldehyde-2% used to kill bacteria, fungi, viruses, 10 min. 10 hr-sterilizes. safer, less irritating than Formaldehyde-37% used for embalming, disinfection. Irritates mucous membranes, and carcinogenic.
Term
Gaseous Agents
Definition
Sterilize heat sensitive items, highly reactive, sporocidal, very effective, but many hrs. Ethylene oxide-Chambers in hospitals and dentists, explosive, poisonous. Propylene oxide-Same. Beta-propiolactone-same, carcinogenic
Term
Enzymes
Definition
Antimicrobial enzymes can kill microbes. (ex:lysozyme (tears), prionzyme (mad cow)
Term
Antimicrobials
Definition
Antibiotics-chem produced by microbes that kill other microbes.
Semisynthetics-Chem modified antibiotic
Term
Development of Resistant Microbes
Definition
Overuse of disinfectants? like Triclosan. Never see resistance to ones that destroy cell membranes
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