Deconjugation of bile acids by human intestinal bacteria implanted in germ-free rats.

Fecal bile acids in germ-free rats were analyzed after inoculation with Bacteroides vulgatus, Bifidobacterium longum, Escherichia coli or Clostridium ramosum. B. vulgatus preferentially deconjugated tauro-beta-muricholic acid and B. longum taurocholic acid. C. ramosum deconjugated both bile acids, but E. coli deconjugated neither. 7 alpha-Dehydroxylation of bile acids was negligible even after 18 days of inoculation, but a small amount of 7-oxo-bile acids, less than 5%, was formed. Fecal excretion of bile acids increased after inoculation with B. vulgatus, B. longum and C. ramosum, but not with E. coli.