While proton-pump inhibitors have been linked to an increased risk of enteric infections such as C. difficile, a US study has found they do not affect the overall composition of the microbiome.

In what is claimed to be the first major study of the effect of PPIs on small intestinal microbiota, researchers from Cedars-Sinai Medical Center, Los Angeles, obtained duodenal aspirates from 148 patients undergoing endoscopy, of whom 36 were taking PPIs.

The microbiome composition was evaluated by culturing the aspirate on agar plates, with the microbial content analysed by genomic sequencing.

Presenting their findings at DDW 2019 in San Diego, the researchers said their analysis showed that people on PPIs showed similar microbial composition profile at all taxonomic levels when compared to controls not on PPIs. No differences were seen in diversity of the small bowel microbiome.

Similarly there were no differences in the incidence of small intestinal bacterial overgrowth with PPI use (30.5%) or without PPI use (29.5%).

The researchers said theirs was first large scale small bowel aspirate study to evaluate PPI use and the small intestinal biome, and it had found no changes in microflora composition or diversity associated with PPI.