A technician is reading a sputum 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 wide,deep,clear zone of b-hemolysis around and under the colonies.What organism could this be?
A) Escherichia coli
B) Staphylococcus aureus
C) Streptococcus pyogenes
D) Streptococcus pneumoniae

Question

Quizplus · Accepted Answer

E.coli will grow on all three plates,not just SBA and CHOC.Staphylococcus aureus will produce b-hemolysis on the SBA plate,but it is not characteristic of Streptococcus pyogenes.Streptococcus pyogenes will produce a wide,deep,clear zone of b-hemolysis on SBA.Streptococcus pneumoniae produces a-hemolysis on SBA.

A Technician Is Reading a Sputum Culture on the Bench