Question

Which hemolysis test (alpha beta gamma) is S. epidermidis positive for?

1) Alpha
2) Beta
3) Gamma

Answer 1

S. epidermidis is positive for gamma hemolysis, indicating no hemolysis. Gamma hemolysis refers to visible bruising of the red blood cells. Alpha and beta hemolysis involve different levels of red blood cell lysis.

Step-by-step explanation:

S. epidermidis is positive for gamma hemolysis, as it forms gray, nonhemolytic colonies on blood agar (BAP) plates. Gamma hemolysis refers to no hemolysis, where the red blood cell membrane is not ruptured but visibly bruised. In contrast, alpha-hemolysis and beta-hemolysis involve different levels of red blood cell lysis. Alpha-hemolysis is a partial lysis, while beta-hemolysis is complete lysis of red blood cells.