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Alpha and gamma-hemolysis on sheep blood agar. Cultivation 48 hours in an aerobic
atmosphere, 37°C. Skin flora.
Species of Streptococcus are classified based on their hemolytic properties. Alpha hemolytic species cause oxidization of iron in hemoglobin molecules within red blood cells, giving it a greenish color on blood agar. Beta hemolytic species (e.g., Staphylococcus aureus, Streptococcus pyogenes, Streptococcus agalactiae)cause complete rupture of red blood cells. On blood agar, this appears as wide areas clear of blood cells surrounding bacterial colonies. Gamma-hemolytic species (e.g., Enterococcus faecalis, Moraxella catarrhalis, Neisseria meningitidis) cause no hemolysis.
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