Refining small intestinal bacterial overgrowth diagnosis by means of carbohydrate specificity: a proof-of-concept study

Abstract

Background: Diagnosis of small intestinal bacterial overgrowth (SIBO) remains challenging. This study aimed at proving the diagnostic concept of carbohydrate-specific SIBO (cs-SIBO) using glucose, fructose and sorbitol hydrogen (H 2 )/methane (CH 4 ) breath testing (HMBT). Methods: In this study 125 patients referred to our outpatient clinic for SIBO testing were included. All individuals underwent glucose (50 g), fructose (25 g) and sorbitol (12.5 g) HMBT at 3 consecutive days. Patients with cs-SIBO (i.e. early H 2 /CH 4 peak) were given rifaximin (600 mg/day) in a 10-day treatment. HMBT results were reassessed in a subset of patients 3-6 months after antibiotic therapy. In view of cs-SIBO diagnosis, agreements between HMBT results obtained for different sugars were calculated using Cohen's kappa (κ) with 95% confidence intervals (CIs). Results: A total of 59 (47.2%) patients presented an early H 2 /CH 4 peak with one or more sugars. Among these, 21 (16.8%), 10 (8.0%) and 7 (5.6%) individuals had a positive HMBT result with either glucose, fructose or sorbitol, respectively. Another 21 (16.8%) patients with a positive glucose HMBT result were also found positive with an early H 2 /CH 4 peak obtained after ingestion of fructose and/or sorbitol. Fair agreement was observed between glucose and fructose (κ = 0.26, p = 0.0018) and between glucose and sorbitol (κ = 0.18, p = 0.0178) HMBT results. Slight agreement was observed between fructose and sorbitol (κ = 0.03, p = 0.6955) HMBT results only. Successful antibiotic therapy with rifaximin could be demonstrated in 26/30 (86.7%) of patients as indicated by normal HMBT results and symptom remission. Conclusions: Combined glucose, fructose and sorbitol HMBT has the potential to optimize cs-SIBO diagnosis. Furthermore, the majority of patients with cs-SIBO seem to benefit from rifaximin therapy regardless of its carbohydrate specificity.

Prevalence and Factors Associated With Small Intestinal Bacterial Overgrowth in Patients With Crohn’s Disease: A Retrospective Study at a Referral Center

“…Crohn's disease (CD) is a multisystemic chronic inflammatory disease that is transmural, immune-mediated and, thus far, incurable and affects any part of the gastrointestinal tract (8) . SIBO seems to be a common condition in patients with CD, with an estimated prevalence between 25% and 88% (2) , and predominant in patients with gastrocolic or jejunocolic fistulas, stasis of intestinal contents, colo-ileal reflux caused by the loss of the ileocecal valve, surgical blind loop, intestinal obstruction and different types of motility disorders (1,9) .…”

Does Irritable Bowel Syndrome Exist? Identifiable and Treatable Causes of Associated Symptoms Suggest It May Not

“…Because refined sugars can be rapidly metabolized by microbiota in the small intestine they could play a contributory role to the development of SIBO. Importantly, carbohydrate intolerance (lactose, fructose and sorbitol) is common among patients with SIBO and may improve after eradication of bacterial overgrowth [64,189]. A low-fermentable carbohydrate diet such as the low FODMAP diet, or restriction of refined carbohydrates, sugars and gas-producing foods could be clinically useful [190].…”