Dynamic Changes in Small-Intestinal Bacterial Overgrowth Following Stricture-Directed Interventions in Patients With Crohn’s Disease: A Prospective Cohort Study

Background/Aims: Prospective data regarding small-intestinal bacterial overgrowth (SIBO) in patients with Crohn's disease (CD) are limited, and the influence of small-bowel strictures on SIBO as well as the effects of stricture-directed interventions remain unclear.Methods: Patients with CD were classified into stricture and non-stricture groups on the basis of the findings of double-balloon enteroscopy or cross-sectional imaging.Healthy controls (HCs) were included.All participants underwent glucose hydrogen-methane breath testing, and SIBO was diagnosed according to the North American Consensus criteria.Primary analyses used pre-intervention tests, whereas secondary analyses assessed changes after endoscopic balloon dilation (EBD) or surgery.Results: Hydrogen-type SIBO (H-SIBO) was not detected in HCs (0/33) but was observed in 3 of 32 patients with CD (9.4%; P = 0.114).H-SIBO was observed in patients with strictures (3/17) but not in those without strictures (0/15; P = 0.229).Three patients who initially showed negative results for H-SIBO showed positive results after EBD of the ileum or ileal surgery; thus, H-SIBO was observed in 6/32 CD cases (18.8%;P = 0.011 vs. HCs; sensitivity analysis including post-intervention tests).Methane-type SIBO was detected in one HC participant (1/33) but was not observed in patients with CD before or after the intervention.Conclusions: In this prospective cohort study, the prevalence of H-SIBO in Japanese patients with CD appeared to be lower than that reported previously.Severe small-bowel strictures may cause false-negative glucose breath-test results, and stricture-directed interventions may reveal previously undetectable bacterial overgrowth.These findings indicate dynamic changes in SIBO status following such interventions, although the results should be interpreted with caution given the limited sample size and methodological constraints.