VUMIE Online - Section 2

Worksheet – ID strategies for gram negatives

Section 1

Indicate whether the following statements are true or false.

1. Bacterial identification is based on comparing results of your unknown with results from known strains of bacteria

2. Bacterial identification is based on a process of elimination based on opinions of scientists

3. Bacterial ID in VUMIE Online cannot be corrected if a mistake is made along the way

4. You cannot eliminate bacteria based on a test result of d, {-}, or {+}

5. Sources for clues to the identity of your unknown include colony appearance, staining results, and biochemical tests.

6. The best source of information on which test to do next in your identification journey is your Lab Report.

7. Smart testing avoids lots of tests with {+}, d, and {-}

8. Smart testing has roughly the same number of + and – outcomes for the test

9. Smart testing begins with a set of standard tests commonly used for unknowns of this type

10. Basic tests for identifying Gram negative bacteria include indole production, growth on bile, and esculin hydrolysis.

11. Basic tests for identifying Gram negative bacteria include acetoin production, motility, and citrate use.

12.  If zero organisms are left in the matrix after conducting a test, you have successfully identified your unknown.

13. When you change the result for a test from + to –, the list of possible IDs for your unknown is modified

14. When you change the result for a test from – to +, the software suggests which other tests should be repeated

15. “Save The Patient” unknowns give you three days to complete the identification of the microbe.

16. “Save The Patient” unknowns give you three days to complete the set of basic tests recommended

17. “Save The Patient” unknowns give you three days to prescribe which antibiotic would be effective for treatment

18. Use of data to eliminate candidate microbes during the ID process is considered inductive reasoning

19. A test result of + or {+} indicates at least half of the strains tested were positive for the test

20. For the VUMIE Online Gram negative bacteria, motility is a useless test

Section 2

Using the image below, indicate whether the following statements are true or false.

21. Cellobiose fermentation is the most useful ID test for these bacteria

22. Arginine dihydrolase would be a useful test for these bacteria

23.  B. agrestis and C. amalonaticus cannot be distinguished from one another based on these tests

24. C. davisae, C. lapagei, and C. neteri cannot be distinguished from one another based on these tests

25. Two good tests to distinguish between B. agrestis and C. davisae would be arabinose or arabitol fermentation tests

26. Two good tests to distinguish between Cedecea neteri and Citrobacter amalonaticus would be adonitol or arabinose fermentation tests

Section 3

Using the image below, indicate whether the following statements are true or false.

27. Malonate and melibiose would be good tests to do, because a positive result provides the ID of the microbe

28. Proteus vulgaris is the only organism giving positive results to lipase, maltose, and methyl red tests

29.  Mannitol fermentation would be useful in distinguishing between Providencia rettgeri and Providencia rustigiani

30. Methyl red is a useful test here because two of the six microbes do not give result of +

31. The tests shown here cannot distinguish between Providencia alcalifaciens and Providencia stuartii

32. If you considered ALL tests in the matrix, it would take a minimum of 5 tests to separate out these 6 bacteria and provide an ID for each