BIO 2420

1. BIO 2420 Intro to Microbiology Sample Comprehensive Laboratory exam Created by R. Rohde www.austincc.edu/rohde

2. Identify the gram reaction seen at the pointer. • Identify the morphology (shape). • Identify the arrangement.

3. Identify the staining technique. • What is the purpose of the white structure seen at the pointer. • 13. Why is an acidic dye used for this technique?

4. Identify the staining technique. • Identify the purpose of iodine in this technique. • Name the primary morphology seen in the slide. • Name the most likely Genus and species seen in this image.

5. 22. Identify the method. 23. What is the purpose of this method?

6. A B C 36. Identify which tube illustrated a non-motile organism.

7. 37. Identify microscope part # 1 • 38. What is the magnification of • part #1? • 39. Identify microscope part # 6 that is • labeled 10X. • What is the magnification when • using the oil immersion objective lens?

8. B A • Identify the bacteria that is found on plate A. • Identify the bacteria that is found to produce the green/blue pigment seen • in image B. • 35. Between these two bacteria (A and B), which one produces a soluble pigment?

9. Identify which sector(s) is/are positive for the breakdown of the milk protein • casein. • 2. Name the enzyme that is present when a bacteria can breakdown this protein.

10. 14. In the nitrate reduction test shown above, what two reagents were added to • determine if nitrate reductase is present? • 2nd reagent • What 3rd reagent must be added to the inconclusive tube above to determine if nitrate • has been totally reduced? • If the inconclusive tube stays the same color as above after this reagent (#16 answer) • is added, what does that outcome mean?

11. Identify the end-product that has been produced in the tube on the right. • Identify the amino acid that is the substrate in this test. • For which bacteria, is this test a presumptive test (positive indicator)?

12. Name the test. • Name the pH indicator in this test. • What is the purpose of this test?

13. You have been given a sample of urine to determine whether or not • it’s likely to be a urinary tract infection (UTI). The only information you know • is that you have a gram negative rod in the urine that “swarms” on agar. The • only biochem test you have available in the lab is the urea test and it turns up positive. • Based on this information, what is the most likely organism that is causing this UTI?

14. Based on the observations with hemolytic activity and bacitracin, • identify the genus and species most likely isolated on this plate.

15. Which family of bacteria is the IMViC test useful for most often? • The following results were noted for the IMViC test (+, +, -, -). Based • on these results, what is the identification of the most likely gram-negative • enteric that we’ve studied in our lab? • 47 and 48. If the IMViC results were reversed (-, -, +, +), which two likely gram- • negative enterics would you suspect based on our labs? • 49. Which simple test could one use to differentiate between these two bacteria?

16. The culture turned purple within 15 seconds of adding the oxidase reagent to the swab. Is this a positive or negative test? • Name which bacteria is positive for this test • that also is assachrolytic and produces a bluish- • green pigment.

17. 9. Identify this selective and differential media that allows for • Differentiation between Staph. aureus and Staph. epidermidis. • Name which sector you would find S. aureus. • Name the ingredient that makes this plate “selective”. • Why is sector “1” turning yellow?

18. What does EMB stand for in this test? • Which bacteria are inhibited on this plate? • Name the bacteria isolated on the above plate.

19. Identify which disk the bacteria is totally resistant to. • Identify which disk the bacteria is most susceptible to. • 29 & 30. Name 2 reasons for the colonies seen in the inhibition zone at • the arrow.

20. An enteric culture gave the following results: gram positive cocci, • Gamma/alpha hemolytic, bacitracin negative, optochin negative, • Bile esculin slant tube entirely black, 6.5% NaCl broth turbid. • Based on the results above, name the genus and species of the most • likely bacteria. • Name the beta-hemolytic, gram positive bacteria that is found in • the Group B streptococcus organisms. • A skin swab gave the following results: gram positive cocci, • Catalase positive, halophile, ferments mannitol. Based on these results, • name the most likely genus and species.

21. On this Hektoen enteric media (HE), are the isolated colonies • LF’s or NLF’s? • What other characteristic is observed with the isolated colonies? • Name one bacteria that would give this result.

22. 8. Identify by genus and species.

23. trophozoite cyst • Identify this protozoan that can cause dysentery from drinking • non-purified water when camping, etc. • 13. What class does this protozoan belong to?

24. Identify this flagellate protozoan (genus only). • 27. Name the type of specimen (urine, etc.) one would have to • acquire to view this microbe.

25. Identify the helminth (Genus & species that produces this egg.) • It is the #1 roundworm infection in the USA. • Specifically, how would one obtain a sample of these eggs to ID • them for a clinical diagnosis?

26. Identify this microbe by genus. • Name the class?