Enterococcus faecalis colonies on bile esculin agar. The ability to hydrolyze esculin in the presence of bile is a characteristic of enterococci and group D streptococci. Esculin hydrolysis is resulting in the blackening of the medium around the colony. Bile salts inhibit gram-positive bacteria other than enterococci. Viridans streptococci sometimes exhibit a weak positive reaction. Also, Leuconostoc, Pediococcus, Lactococcus species causing human infections give a positive bile esculin test.
Cultivated 24 hours at 37°C in an aerobic atmosphere.