Fecal microbiome profiles in uncomplicated right colonic diverticulitis: An exploratory prospective case–control study

Right colonic diverticulitis is common in East Asian populations, but its microbiome features remain poorly characterized. This exploratory prospective case-control study compared fecal microbiome profiles between patients with uncomplicated right colonic diverticulitis (URCD) and healthy controls (HC) and explored clinical-course-related patterns. Twenty patients with CT-confirmed acute URCD and ten HC participants underwent stool sampling and 16S rRNA gene sequencing using the EzBioCloud Microbiome Taxonomic Profiling workflow. Alpha and beta diversity did not differ significantly between the overall URCD and HC groups, and no taxon remained significant after false discovery rate correction. In patients sampled before symptom relief, those requiring antibiotics (n = 2) showed nominal enrichment of Proteobacteria compared with those recovering without antibiotics (n = 8) (9.917% [interquartile range, 9.656-10.178] vs. 1.626% [0.650-2.423], p = 0.044; q = 0.467), although these findings were not significant after multiple-testing correction. Among patients who recovered without antibiotics and had documented sampling timing, the Firmicutes-to-Bacteroidetes ratio was higher in the after-symptom relief subgroup (n = 6) than in before-symptom relief subgroup (n = 8) (0.98 [0.710-2.150] vs. 0.22 [0.130-0.340], p = 0.008), and beta-diversity profiles differed between these subgroups (PERMANOVA, p = 0.003). These exploratory findings suggest that fecal microbiome differences in URCD are not clearly detectable in overall case-control comparisons but may show clinical-course-related patterns in selected subgroups. Larger longitudinal studies with serial sampling are needed.