Microbiota pattern in Crohn’s disease depending on the presence of small intestinal bacterial overgrowth

Aim: to evaluate microbiota in Crohn’s disease depending on the presence/absence of small intestinal bacterial overgrowth (SIBO). Patients and Methods: thirteen patients with Crohn’s disease affecting the small intestine were enrolled. Gut microbiota composition was analyzed using the 16S rRNA gene sequencing. 16S rDNA clone libraries were generated similarly. All patients underwent lactulose hydrogen breath test using Gastroplus+ monitor to establish SIBO. A positive lactulose hydrogen breath test indicated SIBO. Results: hydrogen breath test revealed SIBO in 8 patients with Crohn’s disease affecting the small intestine (61.5%). All these patients were women (mean age 40.5 [34.5; 51.2] years). In 5 patients (mean age 32.4 [28.7; 36.5] years), SIBO was not detected. The metagenome analysis of intestinal bacteria identified certain significant differences in microbiota composition in patients with Crohn’s disease depending on the presence/absence of SIBO. In Crohn’s disease affecting the small intestine, SIBO was associated with greater occurrence of Chryseobacterium spp. (р=0.045), Klebsiella spp. (р=0.045), Phocaecola operational taxonomic unit (OTU) (р=0.045), Enterobacteriaceae OTU (р=0.045), Pasteurellales. (р=0.031), Peptoniphilaceae (р=0,023), Solobacterium spp. (р=0.002), Haemophilus spp. (р=0.031), Lachnospiracea OTU (р=0.045), and Bifidobacterium spp. (р=0.019). Conclusions: a taxonomic shift with the reduction of Firmicutes and Bifidobacterium and increase of Proteobacteria (i.e., Klebsiella spp. and Enterobacteriaceae OTU) was revealed in patients with Crohn’s disease and SIBO. KEYWORDS: inflammatory bowel disease, Crohn’s disease, microbiota, small intestinal bacterial overgrowth, hydrogen respiratory test. FOR CITATION: Kulygina Yu.A., Osipenko M.F., Alikina T.Yu. Microbiota pattern in Crohn’s disease depending on the presence ofsmall intestinal bacterial overgrowth. Russian Medical Inquiry. 2022;6(5):221–226 (in Russ.). DOI: 10.32364/2587-6821-2022-6-5-221-226.