Small intestinal bacterial overgrowth and low-grade systemic inflammation in patients with inflammatory bowel disease

Background and Aim: To investigate the incidence of small intestinal bacterial overgrowth (SIBO) and low-grade systemic inflammation in patients with inflammatory bowel disease (IBD). Methods: From August 2018 to December 2019, 71 patients with inflammatory bowel disease were recruited, and 30 healthy people who came to our hospital for physical examinations at the same time were selected as the control group. The lactulose hydrogen breath test (LBT) and methane LBT were used to detect the prevalence of SIBO. The incidence of low-grade systemic inflammation in IBD patients was determined by the fractional exhaled nitric oxide (FeNO) breath test. The chi-squared test was used for statistical analysis. Results: The positive rate of SIBO in the IBD group was 33.8 %, which was significantly higher than that in the healthy control group (6.6 %) (P<0.01). The incidence of SIBO between UC and CD groups was not significantly different (P = 0.551). The SIBO positive rate was significantly increased in CD patients with no ileocecal valve, ileocecal valve malformation, or intestinal stenosis (P<0.05). The SIBO negative rate of IBD patients treated with infliximab (IFX) was significantly higher than that of IBD patients treated with 5-aminosalicylic acid (5-ASA) (P = 0.006). The FeNO positive rate in IBD patients with SIBO was higher (17/24) than that of IBD patients without SIBO (6/47), and the difference was statistically significant (P<0.01). Conclusion: SIBO in IBD patients was significantly higher than in healthy people, but there was no significant difference between UC and CD groups. The combination of the absence of the ileocecal valve, ileocecal valve malformation, and intestinal lumen stenosis was associated with CD combined with SIBO. IBD patients using IFX were less likely to incorporate SIBO than IBD patients using 5ASA. SIBO was associated with a low inflammatory response in IBD patients.