Alterations of gut microbiota in patients with irritable bowel syndrome: A systematic review and meta‐analysis

Abstract Background and Aims Alterations of gut microbiota were assumed to be the etiology and pathogenesis of irritable bowel syndrome (IBS) in some studies. However, alterations of gut microbiota in IBS patients had not been systematically assessed with a meta‐analysis. We performed a mate‐analysis to explore and compare the alterations of gut microbiota in IBS patients from China and other regions around the world. Methods Case–control studies detecting gut microbiota in IBS patients were identified through English and Chinese databases. The standardized mean difference (SMD) with 95% confidence interval (CI) of bacterial counts was calculated. Results Ten studies from China and seven studies from other regions around the world were included in our study. As compared with healthy controls, the SMDs of Bifidobacteria , Lactobacillus , Escherichia Coli , and Enterobacter in Chinese IBS patients were −1.42 (CI: −2.10, −0.75), −0.91 (95% CI: −1.31, −0.52), 0.83 (95% CI: 0.26, 1.40), and 0.57 (95% CI: 0.33, 0.82), respectively. But the SMDs of Bacteroides and Enterococcus were found no significant differences in Chinese IBS patients. However, the SMDs of Bifidobacteria and Bacteroides in IBS patients from other regions were −0.76 (CI: −1.43, −0.09) and 1.17 (CI: 0.00, 2.35), while the SMDs of Lactobacillus , E . Coli , Enterobacter , and Enterococcus were found no significant differences. Conclusions There were alterations of gut microbiota in IBS patients, and it implied that alterations of gut microbiota might be involved in the pathogenesis of IBS. However, the species‐specific alterations of gut microbiota were different between IBS patients from China and other regions.