Secondary bile acids, produced solely by intestinal bacteria, can accumulate to high levels
in the enterohepatic circulation of some individuals and may contribute to the pathogenesis
of colon cancer, gallstones, and other gastrointestinal (GI) diseases. Bile salt hydrolysis and
hydroxy group dehydrogenation reactions are carried out by a broad spectrum of intestinal
anaerobic bacteria, whereas bile acid 7-dehydroxylation appears restricted to a limited
number of intestinal anaerobes representing a small fraction of the total colonic flora …