BILE ESCULIN AGAR 500 grams/bottle

Bile Esculin Agar is ideal for the isolation and differentiation of intestinal enterococci, based on Esculin hydrolysis in the presence of bile. It is also reccomended by ISO 10273 for fermentation studies of esculin by Yersinia. An esculin test shall be carried out to determine presumed pathogenicity since pathogenic Yersinia enterocolitica strains are esculin negative. This test for fermentation of esculin is equivalent to the test for fermentation of salicin. Organisms positive for esculin hydrolysis hydrolyze the glycoside esculin to esculetin and dextrose. The esculetin reacts with the Ferric citrate to form a dark brown or black colony. Bile Salts do not inhibit enterococci while other Gram positive bacteria are inhibited. Beef extract and peptone supply the nutrients essential for growth. Bacteriological agar is the solidifying agent. Tolerance to bile and the ability to hydrolyze esculin constitutes a reliable presumptive test for the identification of Enterococci. The brown color (positive reaction) around the colonies appears after 18-24 hours of incubation at a temperature of 35±2 °C. The presence of intestinal enterococci, is an indicator for faecal contamination, especially when the contamination occurred a long before and the less resistant coliform bacteria, including Escherichia coli, may already be dead when the analysis is carried out.