SUMMARY A variety of strains of Bacteroides fragilis, Clostridium perfringens, Lactobacillus
species, and Enterococcus species were tested in vitro against human whole bile,
conjugated bile acid, and deconjugated bile acid solutions. The test system revealed that all
four groups of intestinal bacteria were sensitive to unconjugated bile acids; however, the
sensitivity varied with the strains tested. Thin-layer chromatography studies revealed that
human whole bile and conjugated bile acid solutions had no inhibitory effect unless bacteria …