A microbiologist is reading a vaginal culture on the bench.There is growth on the sheep blood agar (SBA) and chocolate (CHOC) plates, but no growth on the MacConkey (MAC) plate.The colonies growing on the SBA have produced a narrow, diffuse zone of b-hemolysis around and under the colonies.What organism could this be?
A)Escherichia coli
B)Streptococcus agalactiae
C)Streptococcus pyogenes
D)Streptococcus pneumoniae

Question

Quizplus · Accepted Answer

Streptococcus agalactiae will produce a narrow, diffuse zone of b-hemolysis on the SBA plate.E.coli will grow on all three plates, not just SBA and CHOC.Streptococcus pyogenes will produce a wide, deep, clear zone of b-hemolysis on SBA.Streptococcus pneumoniae produces a-hemolysis on SBA.

A Microbiologist Is Reading a Vaginal Culture on the Bench