P0150 - Diverticulosis and Colonic Mucosa-Associated Microbiota

Ronan Allencherril, MD, Maria Ellionore Jarbrink-Sehgal, MD, PhD, Li Jiao, MD, PhD
Baylor College of Medicine, Houston, TX

Introduction: Diverticular disease is an increasingly common condition, with an estimated prevalence of 50% among those 60 years of age or older. Still, the pathogenesis of the disease is poorly understood. Dietary fiber, red meat, and obesity are known risk factors for diverticulitis, but the role of gut microbiota in diverticular disease is unclear. We examined the association between the mucosa-associated gut microbiota and diverticulosis.

Methods: We performed an age-, race-, and sex-matched case-control study in adult men, including 37 patients with diverticulosis (75 biopsies) vs. 39 controls without colon pathology (68 biopsies). Colonic biopsy was obtained during colonoscopy. Gut microbiota was determined by sequencing the hypervariable region 4 of the 16S ribosomal RNA gene. The sequence reads were processed using DADA2 and the taxonomy was assigned using SILVA 132. We compared the α- and β-diversity, and taxonomic relative abundances between cases and controls using the Mann-Whitney test followed by multivariable analysis. False discovery rate-adjusted P value (q value) < 0.05 indicated statistical significance.

Results: The study included 76 men (63% white, average age 62 years old). There was no significant difference in bacterial α-diversity between cases and controls (Shannon Index, q value= 0.96). The β-diversity significantly differed between the two groups (P value = 0.001). At the phylum level, cases had significantly higher relative abundance of Fusobacteriota (2.12% vs. 1.28%) and Proteobacteria (16.9% vs. 12.0%) than controls (q values < 0.03). At the family levels, cases had lower relative abundance of Bacteroidaceae (20.74% vs 28.0%, q value = 0.05) than controls. At the genus level, cases had significantly lower relative abundance of Anaerostipes (0.15% vs. 0.56%) and Bacteroides (20.7% vs. 28.0%), but higher relative abundance of Megamonas (0.09% vs. 0) (q values < 0.05) than controls. Multivariable negative binomial regression model for panel data confirmed the association between Proteobacteria and Bacteroides after adjusting for age, race, ethnicity, body mass index, smoking, alcohol use, and segment.

Discussion: The composition and structure of the mucosa-associated gut bacteria differed between those with and without diverticulosis. Diverticulosis was associated with more abundant Proteobacteria phylum and less abundant Anaerostipes and Bacteroidetes than those who had a normal colon.


Disclosures:


Ronan Allencherril, MD, Maria Ellionore Jarbrink-Sehgal, MD, PhD, Li Jiao, MD, PhD. P0150 - Diverticulosis and Colonic Mucosa-Associated Microbiota, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.