Gram +/- Cocci

Question 1

Group A Streptococci differ from other beta-hemolytic streptococci because they are…

Answer 1

Bacitracin-sensitive; (Strept Pyogenes)

Question 2

Group B Streptococci differ from other streptococci because they are…

Answer 2

cAMP-test positive; (Strept. agalactiae)

Question 3

What species of Streptococci is part of the normal oral flora in humans and presents as rheumatic fever and subacute infective endocarditis if it gets into circulation.

Answer 3

Streptococcus viridans; (Group C Strept)

Question 4

Define the key feature of Streptococcus pneumonia that distinguishes it from other strept

Answer 4

Optochin-sensitive

Question 5

What key diagnostic feature differentiates Staphylococcus from Streptococcus?

Answer 5

Catalase test is (+) for Staph and (-) for Strept

Question 6

How does Streptococcus pneumonia and viridans differ from Group A and B Strept?

Answer 6

Unlike Groups A and B Strept (which are beta-hemolytic), pneumonia and viridans are both alpha-hemolytic.

Question 7

Gram positive cocci always have “coccus” in their name. List 3 learned in lecture and provide a feature of each.

Answer 7

1. Staphylococcus - catalase (+)
2. Streptococcus - catalase (-)
3. Enterococcus - E faecium is vancomycin-resistant (Linezolid may treat)