Hemolytic Reactions on Sheep Blood Agar Clinical Microbiology Review 157
HEMOLYSIS DESCRIPTION EXPLANATION EXAMPLES
Alpha
Beta
Gamma (nonhemolytic)
Streptococcus pneumoniae, viridans
streptococci, some enterococciGroup A strep, group B strep, Listeria
monocytogenesSome enterococciGreen zone around colony.
May be narrow or wide.Clear zone around colony.
May be narrow or wide.No zone of hemolysis.Partial lysis of RBCsComplete lysis of RBCsNo lysis of RBCs