Validation of Breath Tests in Diagnosing Small Bowel Bacterial Overgrowth (BTO)

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.

Study Overview

• Status: Completed
• Conditions: Malabsorption Syndromes
• Intervention / Treatment: Other: Stable-isotope labeled lactose ureide breath test

• Study Type: Observational
• Enrollment (Actual): 22

Contacts and Locations

Study Locations

• Germany
  • Bonn, Germany, 53105
    • University of Bonn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients with suspected small bowel bacterial overgrowth

Description

Inclusion Criteria:

• Suspected small bowel bacterial overgrowth

Exclusion Criteria:

• Age < 18 years
• Antibiotic therapy

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Breath test; Subjects with suspected SBBO	Other: Stable-isotope labeled lactose ureide breath test; 2 g 13C-labeled lactose ureide orally; Other Names: Lactosyl ureide

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
13CO2 enrichment in breath CO2	3 hours

Secondary Outcome Measures

Outcome Measure	Time Frame
Hydrogen output in breath	3 hours

Collaborators and Investigators

• Sponsor: University Hospital, Bonn

Study record dates

Study Major Dates

• Study Start: October 1, 1997
• Primary Completion (Actual): September 1, 1998
• Study Completion (Actual): September 1, 1998

Study Registration Dates

• First Submitted: March 30, 2009
• First Submitted That Met QC Criteria: March 30, 2009
• First Posted (Estimate): March 31, 2009

Study Record Updates

• Last Update Posted (Estimate): March 31, 2009
• Last Update Submitted That Met QC Criteria: March 30, 2009
• Last Verified: March 1, 2009

More Information

Terms related to this study

• Keywords: small bowel; bacterial overgrowth
• Additional Relevant MeSH Terms: Digestive System Diseases; Metabolic Diseases; Gastrointestinal Diseases; Intestinal Diseases; Malabsorption Syndromes
• Other Study ID Numbers: BTO-0001