2. this will differentiate Staphylococcus aureus from Staphylococcus epidermidis. 3. B. Staphylococcus aureus
4. the plasma clotted (gelled), indicating a positive coagulase, which indicates S. aureus having followed the diagnostic scheme so far. the beta-hemolysis of this particular strain of S. aureus is not diagnostic of the species. Some strains produce the hemolysin, while others don't. 5. B. Alpha hemolytic and small. (There is a greenish color of the red blood cells around the small colonies) 6. B. Perform a Gram stain.
7. D. Gram-positive cocci in chains.
8. C. Catalase test.
9. B. Streptococcus
10. B. Optochin (P disk)
11. this test is used to differentiate different types of alpha-hemolytic streptococci. 12. A. It is viridans streptococci
13. there was no inhibition of bacterial growth around the P disk. This is indicative of viridans streptococci. this is a collection of streptococci normally found in the oral cavity. 14. B. Type 2 is lactose-positive, and type 1 is lactose-negative. 15. C. Citrate test
16. the citrate test will differentiate E. coli from Klebsiella. Normally a battery of test would be performed to separate the numerous species in the family Eneterobacteriaceae. 17. B. The bacteria are citrate-negative.
18. the tube started off with the same green color, so no change occurred. This is in contrast to the tube on the bottom that was inoculated with a citrate-positive bacterium. this means that colony type 2 is normal E. coli. there are many types of E. coli, some that cause different types of disease, and many that do not.