Bile salts mixture

Bile salts mixture is recommended in diverse media like MacConkey Agar, SS Agar, and Violet Red Bile Agar. It increases the selectivity of the media to Enterobacteriaceae by inhibiting Gram-positive bacteria. It is used as a selective agent in culture media for the selective growth of intestinal bacteria like E. coli, other fecal coliforms, and fecal Streptococci. But it is also used as a selective agent in media for the detection of Yersinia enterocolitica, Aeromonas hydrophila, and Vibrio species.

Bile salts mixture is a combination of an organic sodium salt with a conjugate of any of the bile acids along with either glycine or taurine. Bile salts are composed of four different kinds of bile acids - cholic, deoxycholic, chenodeoxycholic, and lithocholic acids. Bile salts are extracted under controlled conditions from purified fresh bile, to be used in bacteriological culture media, where it behaves as a selective inhibitory agent that inhibits Gram-positive bacteria and induced germination. It also inhibits the outgrowth of the germinated spores but does not interfere with the growth of Enterobacteriaceae.

Extracted from purified, fresh bile.