Comparative Analysis of Oral Microbiome in Indian Type 2 Diabetes Mellitus (T2DM) and Periodontitis Cohorts

TL;DR

This study explores how early-onset diabetes and gum disease affect the oral microbiome in Indian adults, revealing changes in microbial networks linked to lifestyle factors.

Contribution

The study identifies keystone taxa and network shifts in oral microbiomes of Indian T2DM and periodontitis patients under adverse lifestyles.

Findings

Healthy individuals with good lifestyles had scaffold-forming oral bacteria like Corynebacterium matruchotii.

Periodontitis and T2DM_P groups showed enrichment of inflammation-related genera like Porphyromonas and Tannerella.

Disease groups exhibited densely connected microbial networks, contrasting with modular networks in healthy individuals.

Abstract

Background: Type 2 diabetes mellitus (T2DM) and periodontitis are highly prevalent immune-inflammatory diseases that interact bidirectionally. However, how early-onset T2DM, periodontitis, and adverse lifestyle behaviors collectively remodel the gingival plaque microbiome at the ecological network level remains poorly understood in Indian populations. Methods: A cross-sectional 16S rRNA gene (V3–V4) sequencing study was conducted on supragingival and subgingival plaque from 60 adults (30–40 years) recruited in Mumbai. Participants were categorized as healthy (H, n = 10), periodontitis (P, n = 10), T2DM (n = 20), and T2DM with periodontitis (T2DM_P, n = 20). Comprehensive demographic, anthropometric, metabolic, periodontal, dietary, lifestyle, and oral hygiene data were collected. Sequence data were processed using QIIME2–DADA2, followed by diversity, differential abundance, and genus-level co-occurrence network analyses (Spearman |r| ≥ 0.6, FDR < 0.05; core prevalence ≥ 70%). Results: α-diversity showed no marked depletion across groups, whereas Bray–Curtis β-diversity revealed significant global separation, with maximal dissimilarity between H and T2DM_P. Healthy individuals with favorable lifestyle behaviors harbored scaffold-forming taxa such as Corynebacterium matruchotii, Lautropia mirabilis, and Capnocytophaga spp. In contrast, P and T2DM_P groups showed enrichment of proteolytic, inflammation-adapted genera including Porphyromonas, Tannerella, Treponema, Fretibacterium, Peptostreptococcus, and Selenomonas. Network analysis revealed a shift from commensal-rich modular networks to densely connected, keystone-centered disease modules. Conclusion: Early-onset T2DM and periodontitis, particularly under adverse lifestyle behaviors, reorganize plaque microbial composition and interaction architecture rather than depleting diversity, highlighting plaque-based keystone taxa and networks as targets for microbiome-informed risk stratification and integrated medical–dental–lifestyle interventions.

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