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15 Cards in this Set
- Front
- Back
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Name the catalase positive GPCs to the genus level.
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Staphylococcus Rothia (+/-)
Micrococcus Dermacoccus Kocuria Arthrobacter Macrococcus Alliococcus (+/-) Kytococcus Planococcus |
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What is the clinical significance of Micrococceae?
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Common inhabitants of skin, relatively low virulence, commonly isolated in setting of catheter
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What is the relative size of Micrococcus to Staph?
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Micrococci are slightly larger to Staph (1 x 1.8um to 0.5 x 1.5)
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Which species of the genus Rothia is a clinically relevant GPC?
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Rothia mucilaginosa
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What does the catalase test detect, what reagent is used, and what reaction is occurring?
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Catalase test detects cytochrome oxidase enzymes, is performed using 3% hydrogen peroxide, and results from H202 being converted into water and oxygen
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Which of the commonly encountered cat pos GPCs can routinely be cat neg or weakly pos?
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Rothia mucilaginosa
Rare strains of staphylococci may be cat neg and some enterococci produce a "pseudocatalase" reaction |
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How can Rothia be differentiated from staphylococci?
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Sticky colony and inability to grow in 6.5% NaCl
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What organisms are novobiocin resistant?
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S. saprophyticus
S. cohnii |
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Small colony variants of S. aureus are often auxotrophic for what?
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Menadione and hemin
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Small colony variants of S. aureus are often resistant to which antibiotics?
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Gentamicin and other aminoglycosides, TMP/SMX, cell wall agents
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How do you identify S. lugdenensis?
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PYR and ornithine decarboxylase positive
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What coag neg staph species are PYR positive?
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S. haemolyticus, S. lugdunensis, S. schleiferi, and S. intermedius
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What may lead to a false negative coagulase test with S. aureus?
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Staphylokinase may lyse clot after prolonged incubation
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What tests differentiate micrococci from staphylococci?
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Bacitracin (Micro S), modified oxidase (Micro pos), furazolidone (Micro R)
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What test is for production of acetoin?
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Voges-Proskauer
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