Aerococcus viridans
Small, grey, semi-transparent, smooth colonies.		The same Blood Agar plate examined with transmitted light. There is a green zone around the colonies. This 'greening' is caused by the accumulation of hydrogen peroxide converting the haemoglobin to methaemoglobin in the agar. Viridans means green.
General characteristics: Gram-positive. Catalase-negative or weakly positive. Oxidase-negative. Attacks sugars by fermentation. Non-motile.
Microscopy: Phase contrast - tetrads