Investigation of Gut Microbiome Alterations in Type 2 Diabetic Patients at Federal Medical Centre Owerri, Imo State

Emerging evidence implicates gut microbiome dysbiosis in the pathophysiology of type 2 diabetes mellitus, yet characterisation of gut microbiome alterations in Nigerian diabetic populations remains largely absent from the literature. This study investigates gut microbiome composition and diversity in type 2 diabetic patients and matched healthy controls at the Federal Medical Centre, Owerri, Imo State, South East Nigeria. Stool samples were collected from 40 type 2 diabetic patients and 40 age- and sex-matched healthy controls. DNA was extracted from stool samples and the V3-V4 region of the 16S rRNA gene was sequenced using Illumina MiSeq. Operational taxonomic unit clustering and alpha and beta diversity analyses were performed using QIIME2 and R packages. Gut microbiome alpha diversity was significantly lower in diabetic patients than controls (Shannon index, p = 0.008). A significant reduction in Firmicutes/Bacteroidetes ratio was observed in diabetics. Faecalibacterium prausnitzii, an anti-inflammatory butyrate producer, was markedly depleted in diabetics, while Enterobacteriaceae were over-represented. Metformin use was associated with distinct microbiome profiles distinct from diet-controlled diabetics. The study establishes the first 16S rRNA-based gut microbiome dataset in an Imo State diabetic cohort, providing a research foundation for microbiome-targeted probiotic intervention studies in Nigerian type 2 diabetes management. Keywords: gut microbiome, type 2 diabetes, 16S rRNA, dysbiosis, Imo State