A throat swab specimen was cultured on a blood agar plate.Colonies are formed,which produce a greenish halo around the colonies.These bacteria are exhibiting

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The greenish halo around the colonies indicates alpha hemolysis, where the bacteria partially break down red blood cells and produce a greenish discoloration due to the breakdown of hemoglobin. Gamma hemolysis does not cause any visible change in the blood agar plate, beta hemolysis causes complete lysis of red blood cells, and lactose or mannitol fermentation has nothing to do with hemolysis.

A Throat Swab Specimen Was Cultured on a Blood Agar