Fructan‐sensitive children with irritable bowel syndrome have distinct gut microbiome signatures

Abstract

Dietary fructans may worsen gastrointestinal symptoms in children with irritable bowel syndrome (IBS). To determine whether gut microbiome composition and function are associated with childhood IBS fructan-induced symptoms. Faecal samples were collected from 38 children aged 7-17years with paediatric Rome III IBS, who previously completied a double-blind, randomised, placebo-controlled crossover (fructan vs maltodextrin) trial. Fructan sensitivity was defined as an increase of ≥30% in abdominal pain frequency during the fructan diet. Gut microbial composition was determined via 16Sv4 rDNA sequencing. LEfSe evaluated taxonomic composition differences. Tax4Fun2 predicted microbial fructan metabolic pathways. At baseline, 17 fructan-sensitive (vs 21 fructan-tolerant) subjects had lower alpha diversity (q<0.05) and were enriched in the genus Holdermania. In contrast, fructan-tolerant subjects were enriched in 14 genera from the class Clostridia. During the fructan diet, fructan-sensitive (vs tolerant) subjects were enriched in both Agathobacter (P=0.02) and Cyanobacteria (P=0.0001). In contrast, fructan-tolerant subjects were enriched in three genera from the Clostridia class. Comparing the fructan vs maltodextrin diet, fructan-sensitive subjects had a significantly increased relative abundance of Bifidobacterium (P=0.02) while fructan-tolerant subjects had increased Anaerostipes (P=0.03) during the fructan diet. Only fructan-sensitive subjects had a trend towards increased predicted β-fructofuranosidase during the fructan vs maltodextrin diet. Fructan-sensitive children with IBS have distinct gut microbiome signatures. These microbiome signatures differ both at baseline and in response to a fructan challenge.