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Alpha Strep
Question | Answer |
---|---|
What two groups are alpha hemolytic? | 1) Streptococcus viridans 2) Streptococcus pneumoniae |
How does S. pneumoniae usually appear on gram stain and what is the colony morphology on agar? | Gram positive cocci, sometimes lancet shaped It can be round, wet, and mucoid dome shaped, "green snot." It can also look collapsed in the center of the colony (umbilicated or donut). |
What are two main tests used to identify S. pneumonia and what would the results look like? | Optochin/P disk susceptibility: Zone of inhibition (12-15mm) = positive for S. pneumo. Other AHS are resistant. Bile Soubility: Agar: Colony is disintegrated = positive for S. pneumo. Broth: Turbid suspension becomes clear = positive for S. pneum |
What is the major cause of bacterial endocarditis in the U.S.? | Strep viridans |
Nutritionally variant streptococci (NVS) are viridans strep that require what three compounds? | Thiol, cysteine, and vitamin B6 |