[A medium for rapid and economic identification of Escherichia coli lactose+ colonies: brilliant green-bile-lactose-tryptophan broth].

Among 17 lactose-fermenting species of Enterobacteriaceae (735 strains studied), only Escherichia coli could grow at 44 degrees C in brilliant green/ bile/lactose/L-tryptophan broth (BLBVB-T) with production of gas and indole. When the inoculum was from a lactose+ colony developed on selective or differential agar media commonly used in enteric bacteriology, detection of gas and indole in BLBVB-T after 8 to 18 h incubation at 44 degrees C allowed good identification of E. coli. The use of a single-test medium for the identification of lactose+ E. coli saves time and money.