Fecal steroids in diarrhea. II. Travellers' diarrhea

Fecal bile acid and neutral sterol patterns of five healthy adult volunteers from the United States who contracted travellers' diarrhea in Mexico City in 1974 were studied. The only pathogen in four of these patients was the heat-stable-only enterotoxin producing strain of Escherichia coli. Stool culture for pathogens was negative in the fifth subject. Bacterial 7α-dehydroxylation of cholic and chenodeoxycholic acids was not altered in diarrhea associated with toxigenic E. coli heat-stable, although total concentrations of bile acids in the feces in mg/g of feces (wet weight) were decreased during the diarrheal episode (1.3 ± 0.2 versus 3.3 ± 0.4 in controls, P < 0.02). Consistent with findings on bile acids, no significant changes in the production of coprostanol from cholesterol were observed. Although total concentrations of cholesterol metabolites, in milligrams per grams of feces (wet weight), were reduced in diarrhea, the difference was not significant statistically (2.2 ± 0.9 versus 5.4 ± 0.8 in controls, P > 0.05). There was an apparent increase in bacterial alteration of fecal steroids in the subject who showed no pathogens in stool culture, despite a decrease in total steroid concentrations of a magnitude similar to those observed in diarrhea associated with E. coli heat-stable. The production of coprostanol was correlated with 7α-dehydroxylation of cholic acid (r = 0.829, P < 0.001) and chenodeoxycholic acid (r = 0.749, P < 0.001). The results from this study are in striking contrast to the changes in gastrointestinal steroid metabolism previously observed in acute shigellosis.