Biol 251 lab 4

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Biol 251 lab 4
2014-02-28 21:10:26

Lab 4 quiz
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  1. Name a pathogen that produces H2S but does not ferment lactose or sucrose.

    (Page 41).
    • E. Proteus vulgaris
    • F. proteus mirabilis
    • G. salmonella typhimurium
  2. Name a pathogen that may inhabit the stomach and produces the urease enzyme (we can detect it
    using that method; refer to chapter 21 and discuss with your table)?

    (Page 41).
    klebsiella pneumoniae
  3. Name a possible pathogen that is motile and produces indole.

    (Page 41).
    • A. Escherichia coli
    • D. Serratia marcescens
    • E. proteus vulgaris
  4. Name a pathogen that is non-motile but ferments glucose.

    (Page 41).
    • B. Klebsiella pneumoneiae
    • H. Shigella flexneri
  5. Use the color and the results of indole and try to identify your unknown.  How did the
    identification of your bacterial unknown on the Chromagar/Indole compare to the tube
    biochemicals identification?  Was it 100% successful?

    (Page 43).
    No, but close
  6. What is the cellular target of the acid fast stain?

    (Page 53).
    mycolic acid in the cell wall
  7. What genera of bacteria is typically acid fast?

    (Page 53).
    Mycobacterium and some Nocardia
  8. Discuss two diseases caused by acid fast bacteria.

    (Page 53).
    • Mycobacterium tuberculosis causes Tuberculosis.
    • Myobacterium leprae causes Leprosy
  9. Explain how the acid fast property of the bacterium is a virulence factor?

    (Page 53).
    The myolic acid of myobacterium clump the cells together. it is a virulence factor that allow them to survive in phagocytes and make them resistant to disinfectants & antimicrobial therapy.
  10. If a patient has acid fast bacteria in the sputum specimen they provided, does this mean they have
    tuberculosis?  Why or why not?

    (Page 53).
    Yes, if it is Myobacterium tuberculosis that is an acid fast bacteria that cause tuberculosis.
  11. Explain a screening test and a more definitive test for diagnosis of tuberculosis.

    (Page 53).
    • There are number of tests for tuberculosis.
    • skin testing (screens people with high risk for tuberculosis but may have false results even if it test positive)
    • Chest X-Ray
    • Direct identification of myobacterium tuberculosis in sputum.
    • Cultural isolation & identification
  12. Do animals get tuberculosis?

    (Page 53).
  13. Explain the meaning of tuberculosis as a re-emerging infection.

    (Page 53).
    After tuberculosis had been controlled and the number of infections was reduced around the world, myobacterium tuberculosis developed multi-drug resistance and now the number of infections is on the rise.