Bile Esculin Azide Agar

Bile Esculin Azide Agar is used for isolating and presumptively identifying Group D?Streptococci?based on their ability to hydrolyze Esculin. This glucoside is hydrolyzed to esculetin and dextrose by the bacteria. The former reacts with Ferric Ammonium Citrate to form a dark brown or black complex. Oxgall inhibits Gram-positive bacteria not belonging to the?Enterococci?group, while Sodium Azide inhibits Gram-negative microorganisms. Beef Meat Extract, Pancreatic Digest of Casein, and Yeast Extract provide essential nitrogenous sources and carbohydrates for bacterial growth. Sodium Chloride maintains the osmotic balance and Agar is the gelifying agent.