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30 Cards in this Set
- Front
- Back
What are antibiotics? |
chemical agent that have an important property of selective toxicity |
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What is selective toxicity? |
chemicals have the property of being more toxic to one group compared to another (bacteria and humans) |
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Antibiotic Spectrum |
the spectrum of which bacterial species can be inhibited or killed by an antibiotic (narrow and broad) |
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If a bacteria is sensitive to an antibiotic, it ________ and if it is resistant it ______ |
can be killed; cannot be killed |
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Kirby Bauer Assay |
Assay used to determine the response, spectrum and effectiveness of antibiotics |
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The Zone of Inhibition |
circular area of clearing around the disk post incubation, only if they are sensitive will this appear |
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A dose is? |
the amount of antibiotics that can be consumed, applied or injected into the body. The dose makes the poison. |
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The minimum inhibitory concentration is the |
lowest dose that will inhibit the growth of bacteria |
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MIC Assay |
if the drug can inhibit cell growth at the concentration found in a given tube, then the broth in that tube will remain clear |
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Why is fecal contamination of water a problem? |
This is a problem because when bacteria is present in water that we drink or use, it can cause disease and intestinal disorders in our bodies. This results in nausea, diarrhea and even more sever symptoms that can lead to death. |
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What are some waterborne diseases? |
Salmonella poisoning, Polio, hepatitis a |
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What indicates the presence of fecal contamination? |
Coliforms (are an indicator species) |
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What are coliform? |
Gram - enterobacteriaceae, they are present when there is lactose fermentation. They are adapted to the gut environment, easy to detect, only present when there is fecal contamination and not present when there isn't and their population density ratio is reflective upon the amount of fecal contamination. |
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Most probable number |
estimate of the coliform density based on probability theory...0 1 2 or 3...positive = 5mm bubble |
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EMB medium characteristics |
selective and differential, used during the confirmed test (you inoculate with positive presumptive cells) lactose fermenting cells will be metallic green or dark purple in color |
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Steps of water analysis? |
Presumptive, confirmed, completed |
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Urea Broth tube |
tests and organisms ability to use urea as a source of nitrogen fuchsia color is positive for urea production (alkaline) yellow color is negative for urea production (acidic) |
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Durham Fermentation Tubes |
test for the fermentation of mannitol or lactose acidic pH is yellow and is -/+ for gas and + for acid neutral or alkaline pH is - for gas and - for acid organisms that can ferment and produce lactose and mannitol will produce acid and/or gas. |
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Nutrient Agar |
If an organism can break down gelatin, the broth will be liquid and on a slant (above 32 degrees C) (+) If not, the broth will be solid (below 32 degrees C) (-) |
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Citrate Agar Slant |
Tests and organisms ability to use citrate as a source of carbon pH 7.5 and higher will be blue (+) Neutral pH will be green and (-) |
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Tryptic Soy Agar |
catalase test, positive = bubbling, aerobic, H2O2 |
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SIM Medium Testing |
S- sulfide, positive if black participate forms I- 6 drops Kovac's, positive for indole if red/pink ring (indole= chemical compound present in coal, tar and feces (odor)) M- motile (growth throughout or not) |
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Fluid Thio |
Aero tolerance (aerobic at top, facultative throughout, anaerobic at bottom) |
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Effects of disinfectants and antiseptics |
Static - inhibits microbial growth Cidal- kills microorganisms |
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Uses of disinfectants and antiseptics |
Dis- chemicals that are applied to nonliving or inanimate surfaces or objects Anti-chemicals that are applied to living tissue (mucous membranes, skin) |
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Factors that influence the antimicrobial activity of chemical agents |
pH, temperature, solubility of agent, interactions with other chemical in environment, initial size of population, types of microbes present |
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Phenol |
denatures proteins, disrupts membranes |
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Alcohol |
denatures proteins, disrupts membranes |
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Chlorine |
chemically oxidizes many types of cell components |
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Phenol Coefficient |
Value that can be determined in regards to the relation of a chemical's effectiveness against the disinfectant phenol |