Altered faecal and mucosal microbial composition in post‐infectious irritable bowel syndrome patients correlates with mucosal lymphocyte phenotypes and psychological distress

Summary Background A subset of irritable bowel syndrome (IBS) patients, denoted post‐infectious IBS (PI‐IBS), develop symptoms after an enteric infection. Bacterial dysbiosis and mucosal inflammation have been proposed to be involved in the pathophysiology of this entity. Aim To characterise the mucosal and faecal microbiota in PI‐IBS, general IBS and healthy controls, and to investigate associations between the microbiota and the mucosal immune system. Methods Mucosal biopsies and faeces were collected from 13 PI‐IBS patients, 19 general IBS patients and 16 healthy controls. Global bacterial composition was determined by generating 16S rRNA amplicons that were examined by phylogenetic microarray hybridisation, principal component and redundancy analysis. We correlated previously reported lymphocyte proportions with the microbiota. Results Faecal microbiota composition of PI‐IBS patients differed significantly from both general IBS patients and healthy controls (P