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19 Cards in this Set
- Front
- Back
What media is used for testing throat cultures?
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Blood agar
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How do you test with throat cultures?
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swab the back and sides of the throat, then swabbed on a 5% sheep blood agar plate, and hemolysis is read after incubation
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What is the difference between alpha beta and gamma hemolysis?
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Gamma- no hemolysis, regular colony growth with no change to blood agar
Alpha- Green colony growth on blood agar. partial hemolysis of RBCs. bacteria produce hydrogen peroxide and affect the cells, may have some areas cleared of the RBCs Beta- Complete hemolysis of the blood agar, RBCs are destroyed. clear areas easily discerned on the plate. |
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Which 3 organisms are of concern in throat cultures and what type of hemolysis do they have?
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Staph aureus --beta
strept pyogenes--beta strept pneumoniae--alpha |
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What media was used first in staphylococcus spp. testing? what type of media is it?
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M-staph broth.
enrichment media- selective because it has a level of salt preferable to that organism |
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What media was used second in the staphylococcus spp. testing? How were the results interpreted? What was the confirmation test?
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MSA plate. yellow growth, positive, red or white colonies, negative
coagulase test was confirmation,latex beads with rabbit plasma agglutination is positive |
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How many people typically carry S. aureus? more on fomites or people? why?
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30% of the population. more on fomites ?
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Phenol Red
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Mannitol Lactose, Glucose
Reaction red- negative yellow- positive Enzyme sugar fermentation--->acid production |
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MR
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Reaction
red--postive no color change--negative Enzyme glucose-->mixed acid fermentation (presence of hydrogenlyase) |
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VP
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Enzyme
glucose-->pyruvic acid-->acetoin Reaction copper or yellow-negative red- Positive |
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Catalase
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Enzyme
Hydrogen peroxide-->water and O2 (presence of catalase) Reaction bubbles-positive no bubbles-negative |
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Oxidase
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Enzymes presence of oxidase
no color negative purple positive |
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Starch Hydrolysis
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presence of amylase
halo positive no halo negative |
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Gelatine
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presence of gelatinase
solid-negative liquefaction-positive |
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Urease
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presence of urease
pink-positive no color change-negative |
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Hydrogen Sulfide Production (SIM)
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Cysteine desulfurase
black precipitate positive no black precipitate negative |
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Indole (SIM)
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presence of tryptophanase
no color change-negative red/pink layer-positive |
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Citrate Utilization
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presence of citrase enzyme
green negative blue with growth-positive |
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Litmus milk
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Reductase (white positive)
proteolytic enzymes (watery positive) lactic acid and casein (clumps) |