Abstract

Background Many studies have reported significant changes in intestinal microbiota in irritable bowel syndrome (IBS) patients based on quantitative real-time PCR analysis.

Aims We aimed to review the alterations in intestinal microbiota.

Methods An online search up to June 9, 2016, was conducted. This systematic review and meta-analysis included differential expression of intestinal microbiota in patients with IBS versus healthy controls (HCs) and subgroup analysis. We assessed the quality of the included studies using an original assessment tool.

Results A total of 13 articles involving 360 IBS patients and 268 healthy controls were included. The quality assessment scores for these articles ranged from 5 to 8. Significant differences in expression in IBS patients were observed for Lactobacillus (SMD = −0.85, P < 0.001, I2 = 28%), Bifidobacterium (SMD = −1.17, P < 0.001, I2 = 79.3%), and Faecalibacterium prausnitzii (SMD = −1.05, P < 0.001, I2 = 0.0%) but not Bacteroides-Prevotella group, Escherichia coli or other genera or species. Subgroup analysis showed that diarrhea-predominant IBS patients had significantly different expression of Lactobacillus (SMD = −1.81, P < 0.001) and Bifidobacterium (SMD = −1.45, P < 0.001).