Mucosal Biofilms Are an Endoscopic Feature of Irritable Bowel Syndrome and Ulcerative Colitis

Abstract

BACKGROUND & AIMS: Irritable bowel syndrome (IBS) and inflammatory bowel diseases result in a substantial reduction in quality of life and a considerable socioeconomic impact. In IBS, diagnosis and treatment options are limited, but evidence for involvement of the gut microbiome in disease pathophysiology is emerging. Here we analyzed the prevalence of endoscopically visible mucosal biofilms in gastrointestinal disease and associated changes in microbiome composition and metabolism. METHODS: The presence of mucosal biofilms was assessed in 1426 patients at 2 European university-based endoscopy centers. One-hundred and seventeen patients were selected for in-depth molecular and microscopic analysis using 16S ribosomal RNA gene amplicon-sequencing of colonic biopsies and fecal samples, confocal microscopy with deep learning-based image analysis, scanning electron microscopy, metabolomics, and in vitro biofilm formation assays. RESULTS: Biofilms were present in 57% of patients with IBS and 34% of patients with ulcerative colitis compared with 6% of controls (P < .001). These yellow-green adherent layers of the ileum and right-sided colon were microscopically confirmed to be dense bacterial biofilms. 16S-sequencing links the presence of biofilms to a dysbiotic gut microbiome, including overgrowth of Escherichia coli and Ruminococcus gnavus. R. gnavus isolates cultivated from patient biofilms also

Bile Acid Signaling in Inflammatory Bowel Disease

“…A metabolomic analysis of the biofilm have found an accumulation of taurocholic acid that correlated with fecal BA excretion. Moreover, a correlation of mucus production with total amount of BA was observed in UC patients [38].…”

“…Dietary fiber consumption may help to regulate Th1 immune responses in IBD. The presence of biofilms in UC patients, besides increased bile acids content, has been associated with a decrease in short-chain fatty acid producing bacterial genera, including Faecalibacterium, Coprococcus, Subdoligranulum, and Blautia [38]. Such intestinal biofilms were present in 57% of patients with irritable bowel syndrome [38].…”

“…The presence of biofilms in UC patients, besides increased bile acids content, has been associated with a decrease in short-chain fatty acid producing bacterial genera, including Faecalibacterium, Coprococcus, Subdoligranulum, and Blautia [38]. Such intestinal biofilms were present in 57% of patients with irritable bowel syndrome [38]. Faecalibacterium prausnitzii, a known producer of anti-inflammatory short chain fatty acids, is highly sensitive to a slight increase in physiological concentrations of bile salts.…”

Gut Microbiota-Derived Metabolites in Irritable Bowel Syndrome

“…As such, biofilms can protect the bacteria against external interference and promote gene information and nutrient exchange. In fact, biofilms were detected in 57% of IBS patients, compared to controls (Baumgartner et al, 2021). Bacterial biofilms are associated with gut microbiol dysbiosis and increased levels of intestinal bile acids (Baumgartner et al, 2021).…”

“…In fact, biofilms were detected in 57% of IBS patients, compared to controls (Baumgartner et al, 2021). Bacterial biofilms are associated with gut microbiol dysbiosis and increased levels of intestinal bile acids (Baumgartner et al, 2021). Although existing methods on fecal microbial profile or single genus were difficult to distinguish IBS patients from healthy individuals, which indicates that changes in the gut microbiota of IBS are likely to be a heterogeneous and individualized process.…”