A microbiologist is reading a sputum culture and notices tiny, translucent colonies growing closely around a $\beta$ hemolytic colony on sheep blood agar (SBA). The colonies are growing in the area where the blood has been hemolyzed. What is the probable identity of the organism that is growing closely to the $\beta$-hemolytic organism, and why are they growing in the hemolyzed area?

Question

Quizplus · Accepted Answer

Haemophilus spp. are known to require factor V (NAD) for growth, which can be released from red blood cells when they are lysed by the action of hemolytic organisms. The presence of tiny, translucent colonies growing closely around a β-hemolytic colony on sheep blood agar indicates that these organisms are utilizing the nutrients released from the lysed red blood cells, specifically factor V, which supports the growth of Haemophilus spp.

A Microbiologist Is Reading a Sputum Culture and Notices Tiny β\betaβ

A Microbiologist Is Reading a Sputum Culture and Notices Tiny $\beta$