BBE contains gentamicin at a concentration which inhibits most facultative anaerobes. This medium also contains bile, which inhibits anaerobic gram-negative rods except the B. fragilis group and other bile resistant Bacteroides and Fusobacteria. Esculin in the medium permits recognition of esculin hydrolysis by organisms that produce a brown to black coloration in the medium around the colonies. Hemin is added as a growth factor and allows testing for catalase production. This medium is prepared, stored and dispensed under oxygen-free conditions to prevent the formation of oxidized products prior to use.
LKV contains vancomycin to inhibit the growth of gram-positive microorganisms and kanamycin to inhibit the growth of
gram-negative, facultatively-anaerobic bacilli. The sheep blood in the medium is laked and vitamin K1 is added to facilitate the recovery and pigment production of Prevotella melaninogenica. This medium is prepared, stored and dispensed under
oxygen-free conditions to prevent the formation of oxidized products prior to use.