Bile Esculin Azide Agar, Modified is recommended for rapid, selective detection and enumeration of Enterococci and Group D Streptococci.It is a highly nutritious media because of presence of tryptone, peptone and yeast extract which serve as a source of carbon, nitrogen and essential nutrients. Sodium azide inhibits growth of gram-negative organisms and permits the cultivation of Enterococci and group D Streptococci. Bile inhibits grampositive bacteria other than Enterococci. Sodium citrate acts as a buffering agent. Esculin is hydrolysed by Enterococci and group D streptococci to esculetin which reacts with ferric ammonium citrate to form dark brown or black complex . Bile tolerance of group D Streptococci permits its isolation and identification in 24-48 hours.
1.Isenberg, Goldberg and Sampson, 1970, Appl. Microbiol. 20:433.2.MacFaddin, 2000. Biochemical test for identification of medical bacteria, 3rd ed. Lippincott William & Wilkins, Baltimore,Md.3.Swan, 1954, J. Clin. Pathol., 7:160.