A microbiologist is reading a sputum culture on the bench. There is growth on the BAP and CHOC plates, but no growth on the MAC plate. The colonies growing on the BAP have discolored the media to a green color around and under the colonies. What organism could this be?
A) Escherichia coli
B) Staphylococcus aureus
C) Haemophilus influenzae
D) Streptococcus pneumoniae

Question

Quizplus · Accepted Answer

Streptococcus pneumoniae is known for its ability to discolor blood agar plates (BAP) to a green color due to alpha hemolysis. The lack of growth on MacConkey (MAC) agar, which selects for Gram-negative bacteria, further supports this identification, as Streptococcus pneumoniae is a Gram-positive bacterium.

A Microbiologist Is Reading a Sputum Culture on the Bench