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kris10leejmu
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What is the urease test performed on?
urea test media
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What does an uninoculated urease test look like?
peach
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What does the urease test contain?
- urea
- phenol red - pH indicator
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What color does the media of a urease test turn when the pH is over 8.4?
dark pink
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What does the urease test differentiate?
differentiates the bacteria that produce urease and are able to hydrolyze urea
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What does hydrolysis of urea produce?
alkaline meatbolites (ammonia)
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What does a positive urease test look like?
dark pink
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What does a negative urease test look like?
peach
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The urease test is a good media for distinguishing which bacteria from other enteric bacteria?
Proteus spp
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Before we do the Oxidase test what do we need to determine first?
first determine that the colonies are gram negative
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What does gram negative bacteria produce?
an enzyme called cytochrome oxidase (functions in cellular respiration)
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What does the Oxidase test check for?
the presence of the enzyme cytochrome oxidase
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Which gram negative bacteria is oxidase positive?
Pseudomonas aeruginosa
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Which gram negative bacteria is oxidase negative?
Enterobacteriacease (including E. coli) and Proteus
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What types of Oxidase tests are available?
commercial test pads, liquids, or sticks
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In an Oxidase test, immediate _____ color is positive for oxidase (within 60 seconds).
blue to blue-violet
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After we do the Oxidase test, the oxidase negative bacteria is tested in what?
Enterotube
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After we do the Oxidase test, the oxidase positive bacteria is tested in what?
Oxiferm tube
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How many compartments are there for the Enterotube II system?
12 compartments with 12 different media
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How do we inoculate the Enterotube II system?
- life one colony with the sterile wire at the end of the Enterotube
- withdraw the wire from Enterotube, then twist it almost all of the way back
- simultaneously inoculates all of the compartments
- break off the wire at the crimped area
- use the broken off wire handle to puncture the sides of the aerobic chambers
- incubate
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How long do we incubate the Enterotube?
24 hours
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How do we read the Enterotube?
- results will add up to a five digit code called biocode
- compare code to chart to identify bacteria
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What is the Oxiferm tube?
commercial identification system for oxidase positive bacteria
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How many compartments are there for the Oxiferm tube?
12 different media and tests
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How do we inoculate the Oxiferm tube and read it?
just like we do for the Enterotube II system
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What does the motility tube test for?
detects flagella
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What is the media of the motility tube?
- semisolid to allow for movement
- beef extract and peptones to support growth
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How do we do the motility tube?
- obtain an isolated colony
- transfer it to the motility tube with a transfer needle
- insert and withdraw needle in a straight line in the middle of the media
- incubate 24 - 48 hours
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What does a positive motility tube look like?
bacteria will spread away from the line of inoculation
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What does a negative motility tube look like?
growth only in the line of inoculation
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Other than the motility tube, how else can motility be detected?
motility can also be tested for using the handing drop technique
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