BILE ESCULIN AGAR, MODIFIED

This medium is a modification of Bile esculin agar, that differs in content of bile. The value of bile tolerance together with hydrolysis of esculin as a means of presumptive identification of group D streptococci/ enterococci is widely recognized. Bile esculin agar was formulated by Swan for the isolation and identification of Group D Streptococci from food. This medium was also shows differentiation of Enterobacteriaceae, Klebsiella and Enterobacter-Serratia division from other Enterobacteriaceae genera on the basis of esculin hydrolysis.
The medium contains 2% bile that inhibits gram-positive bacteria other than group D Streptococci and Enterococci. Enterococci and Group D Streptococci hydrolyzes esculin to esculetin and dextrose, which reacts with ferric citrate producing brownish black precipitate. Originally Bile esculin test was used for identification of Enterococci. But it was found that this test is also shared by group D Streptococci and therefore it is recommended that other tests such as salt tolerance be performed while identifying Enterococci.

for isolation and presumptive identi?cation of group D Streptococci/Enterococci from food and pharmaceutical products