# Description of the Distinctive Changes in the Colonic Microbiome Associated with Irritable Bowel Syndrome, Uncomplicated Diverticulitis, and Tubular Adenoma

## TL;DR

This study explores how changes in gut bacteria are linked to three colon-related conditions, finding differences in microbial diversity and balance between helpful and harmful bacteria.

## Contribution

The study identifies distinctive microbiome patterns in irritable bowel syndrome, diverticulitis, and tubular adenoma, highlighting a commensal-pathogenic imbalance in these conditions.

## Key findings

- The microbiome of tubular adenoma patients showed lower diversity and fewer commensal bacteria compared to other groups.
- IBS patients had a lower pathogenic/commensal ratio (2.54) compared to diverticulitis and adenoma patients (ratio of 8).
- Key genera like Escherichia–Shigella and Fusobacteria were more abundant in tubular adenoma patients.

## Abstract

Background: The pathogenesis of various colon-related pathologies, including irritable bowel syndrome, uncomplicated diverticulitis, and tubular adenoma, remains unknown, primarily due to their multifactorial nature. These gastrointestinal diseases are increasing in prevalence in Western countries and are common conditions worldwide. Objective: To identify intestinal microbiota signs and their associations with the development of colonic pathologies, such as irritable bowel syndrome, uncomplicated diverticulitis, and tubular adenoma. Materials and Methods: An observational, prospective, cross-sectional study was conducted to compare the microbiome among three conditions via 16S rRNA sequencing of biopsy samples obtained via colonoscopy. Results: The microbiome of individuals with tubular adenoma was less diverse than that of patients with diverticulitis and irritable bowel syndrome, with a lower abundance of commensal bacterial genera, such as Catenibacterium, Bifidobacterium, and Faecalibacterium, and an increase in several genera with known pathogenic roles, including Escherichia–Shigella, Fusobacteria, Prevotella, and Haemophilus. No significant association was found between the type of pathology and the total pathogenic or commensal disease score; however, a ratio of 2.54 to pathogenic/commensal was observed in the IBS patient group. In contrast, in the diverticulitis and adenoma patient groups, this ratio was 8. Conclusions: These results provide evidence supporting the proposal that alterations in the colonic microbiome could be involved in various colonic pathogeneses and that an imbalance between commensal and pathogenic populations could be directly related to pathogenesis in the microsystem. It is important to highlight the need for future studies.