Overview the type of hemolysis present can be used to classify the bacteria Alpha hemolysis dark and greenish "partial" hemolysis bacteria include Streptococcus pneumoniae Optochin sensitive Viridans group streptococci Optochin resistant Beta hemolysis transparent "complete" hemolysis bacteria include Staphylococcus aureus Streptococcus pyogenes (group A strep) Streptococcus agalactiae (group B strep) Listeria monocytogenes Gamma hemolysis unchanged "no hemolysis" bacteria include Enterococcus faecalis (group D strep) can also be alpha hemolytic Notice that hemolysis is generally used to distinguish strains of Streptococcus, but that Staphylococcus aureus and Listeria also have characteristic hemolytic properties