Gram Negative Media and Testing 2

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  1. What is the urease test performed on?
    urea test media
  2. What does an uninoculated urease test look like?
  3. What does the urease test contain?
    • urea
    • phenol red - pH indicator
  4. What color does the media of a urease test turn when the pH is over 8.4?
    dark pink
  5. What does the urease test differentiate?
    differentiates the bacteria that produce urease and are able to hydrolyze urea
  6. What does hydrolysis of urea produce?
    alkaline meatbolites (ammonia)
  7. What does a positive urease test look like?
    dark pink
  8. What does a negative urease test look like?
  9. The urease test is a good media for distinguishing which bacteria from other enteric bacteria?
    Proteus spp
  10. Before we do the Oxidase test what do we need to determine first?
    first determine that the colonies are gram negative
  11. What does gram negative bacteria produce?
    an enzyme called cytochrome oxidase (functions in cellular respiration)
  12. What does the Oxidase test check for?
    the presence of the enzyme cytochrome oxidase
  13. Which gram negative bacteria is oxidase positive?
    Pseudomonas aeruginosa
  14. Which gram negative bacteria is oxidase negative?
    Enterobacteriacease (including E. coli) and Proteus
  15. What types of Oxidase tests are available?
    commercial test pads, liquids, or sticks
  16. In an Oxidase test, immediate _____ color is positive for oxidase (within 60 seconds).
    blue to blue-violet
  17. After we do the Oxidase test, the oxidase negative bacteria is tested in what?
  18. After we do the Oxidase test, the oxidase positive bacteria is tested in what?
    Oxiferm tube
  19. How many compartments are there for the Enterotube II system?
    12 compartments with 12 different media
  20. 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
  21. How long do we incubate the Enterotube?
    24 hours
  22. How do we read the Enterotube?
    • results will add up to a five digit code called biocode
    • compare code to chart to identify bacteria
  23. What is the Oxiferm tube?
    commercial identification system for oxidase positive bacteria
  24. How many compartments are there for the Oxiferm tube?
    12 different media and tests
  25. How do we inoculate the Oxiferm tube and read it?
    just like we do for the Enterotube II system
  26. What does the motility tube test for?
    detects flagella
  27. What is the media of the motility tube?
    • semisolid to allow for movement
    • beef extract and peptones to support growth
  28. 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
  29. What does a positive motility tube look like?
    bacteria will spread away from the line of inoculation
  30. What does a negative motility tube look like?
    growth only in the line of inoculation
  31. Other than the motility tube, how else can motility be detected?
    motility can also be tested for using the handing drop technique
Card Set:
Gram Negative Media and Testing 2
2013-02-17 02:26:37
Microbiology Four

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