Duodenal bile acids among children: keto derivatives and aerobic small bowel bacterial overgrowth.

Duodenal bile acids, identified by gas-liquid chromatography (GLC) and gas chromatography-mass spectrometry (GC-MS), were correlated with quantitative aerobic and anaerobic duodenal culture in 26 children with enteropathies. Four patients whose duodenal fluid contained either greater than or equal to 10(6) gram-negative aerobes or greater than or equal to 10(6) aerobic lactobacilli per milliliter had a significantly greater molar percentage of keto-bile acids (32.3 +/- 8.4%) than did 19 controls (0.72 +/- 1.50%) chosen because duodenal fluid contained less than or equal to 10(4) bacteria per milliliter or three other patients with greater than or equal to 10(6) anaerobes (6.1 +/- 4.6%). As expected, free bile acids were seen in greater quantities (10.75 +/- 3.25%) among the patients with anaerobic overgrowth or aerobic Lactobacillus overgrowth than among the controls (1.6 +/- 1.0%) or the other three aerobic overgrowth patients (2.2 +/- 1.4%). Incubation of glycocholate or glycochenodeoxycholate for 60 h with Eubacterium tortuosum from one patient or Escherichia coli from another produced the types of bile acids found in the duodenum of those patients. Successful antibacterial therapy improved gastrointestinal function and normalized duodenal bile acids not only among patients with anaerobic overgrowth but also among those with pure aerobic overgrowth. These data suggest that pure aerobic bacterial overgrowth syndrome occurs in children, and that altered duodenal bile acid composition may play a pathophysiologic role in this disorder.