Biofilms may be ‘tipping point’ in development of dysbiosis, disease in IBS, UC
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Mucosal biofilms are endoscopic features in patients with irritable bowel syndrome and ulcerative colitis with disrupted bile acid metabolism and bacterial dysbiosis, according to a study in Gastroenterology.
“Biofilms correlate with dysbiosis of the gut microbiome and BA malabsorption. [Seventy-one percent of biofilm positive] individuals had observable phenotypes of [Ruminococcus gnavus (R. gnavus)] and/or [Escherichia coli (E. coli)] overgrowth,” Maximilian Baumgartner, MD, from the division of gastroenterology and hepatology, department of internal medicine, Medical University of Vienna in Austria and colleagues wrote. “Biofilms represent a new dimension in understanding GI health and disease and hold the potential to revolutionize diagnostic algorithms and treatment approaches in functional GI disorders.”
Baumgarten and colleagues evaluated the presence of mucosal biofilms in 1,426 patients with IBS and UC at two European university-based endoscopy centers. They selected 117 patients for an in-depth molecular and microscopic analysis with 16S-rRNA 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.
Investigators observed biofilms in 57% of patients with IBS and 34% of those with UC, compared with 6% of control participants (P < .001).
“These yellow-green adherent layers of the ileum and right-sided colon were microscopically confirmed to be dense bacterial biofilms,” Baumgarten and colleagues wrote. “16S-sequencing link 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 formed biofilms in vitro.”
According to results from metabolomic analysis, there was an accumulation of bile acids within biofilms that were associated with fecal bile and excretion. This demonstrated a link between the phenotype and a mechanism of diarrhea.
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