I will assume we are talking about an oral specimen:
beta hemolytic strep, group A probable
beta hemolytic strep, grp C possible
beta hemolytic strep, grp B possible although I would expect this
in other sources
Staph hemolyticus
Staph aureus
Hemophilus parahemolyticus or hemolyticus, as satellite colonies with
Staph present. However, H. parahemolyticus would be tiny on bloods
without Staph present and H. hemolyticus would not grow on blood at all
without Staph present.
More than likely you have a beta-hemolytic strep. Presumptive grouping
can be made on colony morphology although it should not be relied on as
definitive. Small colonies with a zone of complete hemolysis 2-3 times
the size of the colony are probably group A. Slightly larger colonies
with a zone of hemolysis rough 1-1.5 times the size of the colony are
probably group B. Tiny colonies with a zone of hemolysis 3-4 times the
size of the colony are probably group C.
Hope that helps....
