Validation of Breath Tests in Diagnosing Small Bowel Bacterial Overgrowth

Study Overview
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Brief Summary
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Normally the gastrointestinal tract is only sparsely colonized with bacteria. The normal flora of the duodenal or jejunal aspirate contains no more than 10^5 bacteria per milliliter. Small bowel bacterial overgrowth (SBBO) is defined as a pathologically increased number of bacteria or the presence of colonic flora in the proximal intestine. The reasons for this condition are manifold, ranging from diabetic neuropathy to surgical bypass. SBBO is frequent in elderly people. Therapy is targeted at correcting the underlying small bowel abnormalities that predispose to the condition and at providing appropriate antibiotic therapy. The symptoms and signs of SBBO can be reversed with this approach. However, in many patients the conditions predisposing to SBBO persist life-long, once present. This suggests that noninvasive, sensitive diagnostic tools with high specificity are required. Bacterial culture of upper intestinal content is considered the diagnostic gold standard. However, since endoscopic harvesting of duodenal or jejunal fluid is difficult and invasive, indirect tests such as breath tests have been advocated as diagnostic tools. Hydrogen breath tests are commonly employed since the substrates can be easily obtained and the measurement is simple. Hydrogen is formed when carbohydrates are fermented in the intestine. Breath hydrogen analysis allows a separation of metabolic activity of the intestinal flora from that of the host, since no known hydrogen production occurs in mammalian tissue. The hydrogen breath test most often used in routine clinical practice uses glucose. However, the utility of this test is mostly limited by its low sensitivity, because there are nonproducers in up to 25% of the subjects tested. The investigators have developed a stable isotope breath test using 13C-labeled lactose-ureide. Glycosyl-ureides are condensation products of reducing sugars and urea in aqueous acid. Lactose-[13C]ureide has been used to investigate oro-caecal transit time because it resists digestion by small intestinal enzymes and is hydrolyzed by bacterial enzymes in the large intestine. A number of studies have described the use of this substrate in adults and children. The aim of the present study was to investigate the lactose-[13C]ureide breath test in subjects with suspected SBBO and to compare its results with the results of the glucose hydrogen breath test. Microbiological analyses of upper intestinal bacterial cultures were used as gold standard to identify SBBO.

Official Title
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Validation of Breath Tests in Diagnosing Small Bowel Bacterial Overgrowth

Conditions
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Malabsorption Syndromes

Intervention / Treatment
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* Other: Stable-isotope labeled lactose ureide breath test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Suspected small bowel bacterial overgrowth Exclusion Criteria: Age < 18 years Antibiotic therapy

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Breath test<br>Subjects with suspected SBBO | Other: Stable-isotope labeled lactose ureide breath test<br>* 2 g 13C-labeled lactose ureide orally<br>* Other names: Lactosyl ureide;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 13CO2 enrichment in breath CO2 |  | 3 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hydrogen output in breath |  | 3 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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small bowel, bacterial overgrowth