Lower microbial diversity may increase extraintestinal pain, worsen QoL in women with IBS

Stool microbial diversity and composition appear to have a significant effect on daily extraintestinal symptoms, stool consistency and quality of life (QoL) in women with irritable bowel syndrome (IBS), a recent study has shown.

Seventy-six women completed a 28-day diary that included gastrointestinal symptoms, stool consistency, psychological distress and extraintestinal pain ratings, as well as the IBS-Specific Quality of Life questionnaire. Of these, 22 were categorized as IBS constipation, 39 as IBS diarrhoea, 13 as IBS mixed and two as IBS unsubtyped.

The investigators collected and analysed stool samples via 16S rRNA gene sequencing. They also performed principal component analysis and used the first two components (PC1, PC2) to test the relationships among bacterial families and clinical measures.

A significant group effect was observed for the Firmicutes-to-Bacteroidetes ratio and PC1. Lower microbial diversity and richness appeared to increase urgency and extraintestinal pain, worsen QoL, and result in looser stools.

Increased abundances of Rikenellaceae, Christensenellaceae, Dehalobabacteriaceae, Oscillospiraceae, Mogibacteriaceae, Ruminococcaceae, Sutterellaceae, Desulfovibrionaceae and Erysipelotrichaceae correlated with lower extraintestinal pain. A positive association was also found between QoL and several of these bacterial families. In addition, higher Firmicutes-to-Bacteroidetes ratio positively correlated with loose stools.

On the other hand, no statistically significant associations were found between bacterial families and daily psychological distress or abdominal pain.

“Altered microbial diversity has been associated with gastrointestinal symptoms in persons with IBS,” the investigators noted.