Fecal
bile acid and neutral
sterol patterns of five healthy adult male volunteers, who were challenged by a virulent Shigella flexneri 2a (M42-43) strain and developed
dysentery were studied. It was observed that
cholic acid was increased from 1.9 +/- 0.4% of total
bile acid in the feces before
infection to 14.5 +/- 2.1% during
diarrhea (P less than 0.001).
Chenodeoxycholic acid also was increased from 3.2 +/- 0.7 to 8.7 +/- 3.2% in
diarrhea but the difference was not significant statistically. Deoxycholic and lithocholic
acids constituted 34.1 +/- 4.1 and 40.5 +/- 2.8%, respectively, of total
bile acid in the normal controls as compared to 13.9 +/- 2.5 and 24.8 +/- 2.5% for the same subjects during
diarrhea (P less than 0.005). Total excretion of
bile acids, expressed as mg/kg of
body weight per day, were higher in
diarrhea (5.4 +/- 1.0) than that in controls (4,2 +/- 1.0) but the difference was not statistically significant. In the neutral
sterol fraction, unmodified
cholesterol was increased during
diarrhea (86.2 +/- 8.7 versus 25.0 +/- 4.8% of total
cholesterol metabolites in controls, P less than 0.001).
Coprostanol was decreased in
shigellosis (12.2 +/- 8.2 versus 65.8 +/- 4.7% in controls, P less than 0.001).
Epicoprostanol,
coprostanone, and unidentified
cholesterol metabolites also were reduced in
shigellosis. The effect of
diarrhea on the
plant sterols was not as consistent. However, unidentified
plant sterols were reduced significantly in
shigellosis stools. Total excretion of
cholesterol metabolites and
plant sterols, when expressed as mg/kg of
body weight per day, were 6.8 +/- 1.7 and 0.6 +/- 0.2), respectively, in
Shigellosis. These values were not significantly different from the corresponding values for controls (10.3 +/- 3.0 and 0.8 +/- 0.2). One subject's stool samples were studied during
infection for the sequence of
bile acid alteration. A progressive reduction of bacterial activity upon fecal
steroids was evident following the initial diarrheal episode. The production of
coprostanol was correlated with 7 alpha-dehydroxylation of
cholic acid (r = 0.937, P less than 0.001) and
chenodeoxycholic acid (r = 0.755, P less than 0.01).