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24 Cards in this Set
- Front
- Back
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Bacitracin Susceptibility
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Tests for specific organisms susceptibility to bacitracin
Differentiate between Group A strep (S) and Group B strep (R) Positive result = clearing around AB disc Done on BA plate 35 degrees |
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Bile esculin test
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Determines organisms ability to grow in high bile concentrations and their ability to hydrolyze esculin
Test for Enterococcus positive result is growth AND black color change on the slant. Must use small inoculum to make sure bacteria can grow on media. Also to reduce chance of false positive for esculin hyrdolysis Small inoculum |
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Catalase
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Tests for the presence of catalase, an enzyme that protects against oxidative damage due to hydrogen peroxide
Positive result indicated by bubbles in H2O2 Positive organisms are Staph, Neisseria, Corynebacteria, Listeria, Bacteroides |
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Citrate
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Ability of organism to utilize citrate as SOLE carbon source.
Positive result indicated by growth and blue color shift of agar *Small inoculum is required to prevent addition of additional carbon source |
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Coagulase
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Ability for an organism to coagulate serum
Positive test is a clumping Tests for S. aureus Heavy inoculum needed to make results more easily noticed |
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CTA
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test for sugar oxidation pattern of an organism in different sugars (Glu, Suc, Mal, Lac)
Positive test is no color change (orange) to yellow. Negative test is a pink color change Differentiating test for Neisseria *Neisseria cannot grow on CTA slant. Test determines preformed enzymes and therefore requires a heavy inoculum |
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Ornithine decarboxylase
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tests for ability to decarboxylate ornithine
Glucose is fermented in anaerobic environment changing pH indicator yellow. decarboxylation would change the color back to purple Positive result is no color change (purple) |
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Hemin NAD requirement
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Test for the Hemin and NAD requirements of Haemophilus species
Hemin (X) and NAD (V) strips on a TSY plate Positive determined by satelliting around one or both strips H. flu (X+V) H. para (V) |
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Hippurate
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hydrolysis of hippurate
organism added to hippurate broth with ninhydrin (turns purple in amino acids) Test for group B strep Positive = purple |
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Indole
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tests for tryptophanase activity
Start with tryptone broth and Kovac's reagent tests for indole (byproduct) Positive is red color |
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Spot indole
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test for indole production due to tryptophanase.
positive = pink *Use spot indole reagent which reacts with any indole |
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Latex agglutination
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antibody coated latex beads bind to a specific antigen that is tested for and causes beads to aggregate due to antigen binding
positive result = clumping of latex beads Imporant organisms: beta hemolytic strep, H. flu, Shigella |
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Lecithinase
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test for lecithinase activity of an organism on egg yolk agar
positive result = cloudy white area around streak lecithinase positve organism(s) = C. perfringens |
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LIA
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Tests for lysine decarboxylase/deaminase activity
Bottom of slant - glucose fermentation (-/yellow) --> decarboxylase (basic) (+/purple) Top - glu ferm (acid)-->peptone oxidation (-/purple) --> deamination (+/red) |
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Motility
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Tests for motility of organisms
Positive = cloudy area around stab Negative = growth on stab only Nonmotile: Klebsiella, Shigella |
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Nitrate
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Ability to reduce nitrate anaerobically
Nitrate --> nitrite -->-->-->N2 reagents detect for nitrite and turn red. durham vial detects for production of N2 gas.If not red add zinc dust that binds to NO3 turning red indicting a negative result Important test for Corynebacterium (+) and Listeria (-) |
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Novoboicin
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Test for novo sensitivity
Tests for Staphylococcus epidermidis (S) and Staph. saprophyticus (R) |
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O/F
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Test whether organism oxidizes or ferments certain sugar
yellow in aerobic - oxidation only yellow in both - fermentation blue (no change) - no sugar utilization |
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Oxidase
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test for presence of cytochrome c
positive result = pink imporant organisms - pseudomonas, neisseria spp, campylobacter |
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Salt tolerance
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ability for an organism to grow on 6.5% NaCl
Positive = turbidity and/or yellow color change test for enterococcus |
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Sugar ferments
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Test for ability to ferment a certain sugar
positive result = color change and sometimes gas. Look for whether there is no change or no growth |
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TSI
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Top: Lac/Suc fermentation
Glu ferm --> Lac/Suc ferm (A/yellow) OR peptone oxidation (K/red) bottom glu ferm (A/yellow) |
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Urea hydrolysis
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test for presence of urease (NH3 released
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VP
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Tests for the presence of the butan-diol pathway
add VP A/B reagents and turns red if positive (may have to wait a few minutes) |
