Colony characteristics of bateria on Blood Agar (BA)

1. Streptococcus pyogenes

The Gram positive streptococcus produces pinpoint colonies which are circular with entire margins and convex elevation.

2. Streptococcus pneumoniae

The Gram positive streptococcus produces colonies which are circular with entire margins, often raised with depressed centres. This microbe exhibits alpha haemolysis; a partial breakdown of the red blood cells in the medium.

3. Enterococcus faecalis

This Gram positive coccus forms pinpoint colonies with convex elevation. This strain exhibits gamma haemolysis; growth on Blood Agar Plate but no lysis of the red blood cells in the agar.

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