BILE ESCULIN AZIDE AGAR, MODIFIED

Description

Group D Streptococci possess the group D lipoteichoic acid antigen in their cell walls. Group D species, are predominant normal inhabitants of the human gastrointestinal tract, are termed as faecal streptococci or Enterococci. The unique ability of Enterococci to split esculin was reported by Meyer and Schonfeld. Enterococci and group D streptococci hydrolyze esculin to esculetin and dextrose, which reacts with ferric citrate producing brownish black precipitate. The use of esculin hydrolysis in identification of Enterococci was first cited by Rochaix. However, other tests such as salt tolerance should be performed for identifying Enterococci. Modified Bile Esculin Azide Agar was formulated according to Isenberg et al, Swan, Facklam and Moody and Meyer and Schonfeld. They reported that esculin hydrolysis and bile tolerance permit the isolation and identification of group D streptococci in 24 hours.