Bacterial Contamination of the Small Bowel Evaluated by Breath Tests, ⁷⁵Se-Labelled Homocholic-Tauro Acid, and Scanning Electron Microscopy

Abstract

Eighty-one patients with diarrhoea due to suspected bacterial contamination of the small intestine were investigated with the bile acid breath test (BABT) and ⁷⁵Se-labelled homocholic-tauro acid (SeHCAT), The impact of bile acid malabsorption due to dysfunction of the terminal ileum on BABT was evaluated. The group of patients with abnormal BABT, notably the 6-h accumulated value, showed a high frequency of reduced SeHCAT values (p < 0.01), indicating that a reliable test for bile acid malabsorption is indispensable for interpreting the BABT in the investigation of small-intestinal bacterial overgrowth. The results of the ¹⁴C-D-xylose breath test were compared with the outcome of the combined SeHCAT-BABT in 44 patients. In contrast to previous findings no correlation between the two breath tests was found. On the contrary, a significant negative correlation was encountered (p < 0.01) for patients in whom either breath test was abnormal. Scanning electron microscopy for demonstration of adherent microorganisms was included in the investigations. No correlations were found with the outcomes of the different breath tests. The effect of antibiotic treatment was evaluated with regard to symptoms and breath tests. The results of the investigation indicate that different tests are needed for the diagnosis of bacterial overgrowth of the small intestine, because of the different metabolic-characteristics of the contaminating bacteria.

Key Words:

• Bile acid breath test
• contaminated small bowel
• scanning electron microscopy
• ⁷⁵Se-homocholic-tauro acid
• ¹⁴C-xylose breath test