Lab Test – Microbiology – Flashcards
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| Starch Agar |
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| Use (U): inoculate gel, cells that produce and exocytose amylase will digest starch (+); Gram's Iodine is used to bind starch, turning it brown Results (R): (+) gap in brown coloring around colonies; (-) no gap |
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| O-F Media |
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| U: determine aerobicity of organism; liquid broths are inoculated, one is covered with oil R: aerobes: (+) non-oil, (-) oil; anaerobes: (-)(+); facan: (+)(+); dead: (-)(-); acid: (+) green to yellow |
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| Citrate Slant |
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| U: scrape-inoculate across top of slant, if citrate is present, acid is created turning green agar blue (+) R: (+) blue; (-) green |
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| Urea |
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| U: tests for denitrification (production of N2) as well as metabolism of urea R: (+) gas in catcher, pink broth; (-) yellow broth, no gas |
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| Bile Esculin |
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| U: breakdown of esculin to esculetin, esculetin reacts with bile (brown) R: (+) brown (+)not brown |
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| Phenol Red Broth |
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| U: determination of growth on a particular carbohydrate; growth produces acid, turns broth red R: (+) red (-)not |
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| Methyl Red |
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| U: determine degree of metabolism of carbohydrate R: (+) high acidity, red (-) low-to-no acidity, not red |
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| Voges-Proskauer |
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| U: determine if glucose is digested to acetoin; acetoin reacts with alpha naphthol and KOH turns cherry red R: (+) cherry red (-) yellow-brown |
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| Decarboxylase test |
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| U: measures pH change due to breakdown of arginine, lysine, and/or ornithine R: (+) purple/blue; (-) no color change |
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| Nitrate Reduction |
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| U: nitrate-->ammonia; nitrate broth, trap gas R: (+) bubble (-) no bubble |
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| Fluid Thioglycallate Media |
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| U: determines aerobicity R: Aerobe: all at surface; anaerobe: all away from surface; aerotolerant anaerobe: evenly distributed; facan: most at surface, but also elsewhere |
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| Milk agar |
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| eats up casein or doesn't +: blank areas around colonies -: continuous whiteness |
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| gelatin agar |
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| eats gelatin or doesn't +: becomes liquid -: remains solid |
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| DNase agar |
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| breaks down DNA or doesn't +: blue (breaks it down forms acid) -: not (doesn't) |
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| Lipase agar |
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| lipolysis capacity +: clear patch around colonies -: continuous blueness |
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| Nutrient agar |
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| no test other than presence and growth (used for isolation) |
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| SIM |
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| H2S and indole production, motility +++: black spots, red reaction to Kovac's reagent, spread from insertion -++: no black spots +-+: no reaction to Kovac's ++-: no spread |
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| KIA |
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| glucose/lactose fermentation; h2s production; gas production; inoculate slant and stab ++++: yellow butt, yellow slant, black butt, and crack/bubble ----: red butt, red slant, no black, no crack/bubble |
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| CNA agar |
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| blood agar, selective for gram positive, differential based on hemolysis R: alpha: greenish; beta: turns gel bright yello; gamma: blueish |
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| Desoxycholate agar |
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| fermentation of lactose determinatoin by red pH indicator; selective for gram negative R: +: red colonies -: colorless colonies |
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| Methylene Blue agar |
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| fermentation of lactose and/or sucrose dyes eosin Y & methylene blue; selective for gram negative R: coliforms: blue-black; salmonella/shigella: colorless/amber; e coli: metallic green |
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| Hektoen Enteric Agar |
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| U: lactose/sucrose/salicin fermentation (acid fuchsin/bromthymol blue); selective for gram negative R: yellow/salmon: E. coli, entero, kleibs blue-green: proteus, salmonella green/moist: shigella green-brown: pseudomonas |
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| MacConkey Agar |
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| Lactose fermentation determination; selective for gram negative rods |
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| Mannitol Salt |
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| Determines if organism grows on mannitol/is halotolerant R: +mann: yellow +growth: halotolerant |
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| Phenylethyl alcohol agar |
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| selective for gram positive |
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| catalase test |
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| if organism synthesizes and secretes catalase, administration of H2O2 will produce O2 gas +: bubbles; -: no bubbles |
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| oxidase test |
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| testing presence of cyt. c oxidase (ETC) with sterile swab and a drop of tetramethyl-p-phenylenediamine R: +: purple quickly -: no/slow color change |
