A comparative analysis of oral microbial communities in hypertensive patients with and without chronic periodontitis

Hypertension and chronic periodontitis are both highly prevalent diseases with a well-established association. Dysbiosis of the oral microbiota, a key factor in oral health, may contribute to the mechanisms underlying their comorbidity. This study aimed to characterize the oral microbiota in hypertensive patients with and without periodontitis and explore its potential role in this disease association. Saliva samples from hypertensive patients without periodontitis (T, n = 17), periodontitis patients without hypertension (P, n = 18), comorbid patients (TP, n = 16), and healthy controls (HC, n = 16) underwent 16S rRNA gene (V3-V4) sequencing. Microbiota composition, diversity, differential taxa, and predicted function were analyzed. Alpha diversity (Chao1/Ace indices) was significantly higher in HC versus disease groups (P < 0.05), while beta diversity showed greater similarity among disease groups but marked divergence from HC (P < 0.05). At genus/species levels, disease groups exhibited characteristic dysbiosis: the abundance of health-associated taxa decreased, while classic periodontal pathogens were significantly enriched. Notably, Streptococcus sp. I-G5 was uniquely enriched in the T group. Functionally, disease groups exhibited enriched lipid metabolism, immune response, and oxidative stress pathways (P < 0.05), contrasting with HC group dominance in xenobiotic biodegradation and amino acid metabolism. Ten differentially abundant genera and eleven species distinguished disease states, highlighting microbiome dysbiosis and metabolic shifts in oral-systemic disease interactions. The oral microbial community of hypertensive patients exhibited dysbiosis analogous to those observed in periodontitis, characterized by a reduced alpha diversity, an enrichment of periodontal pathogens, and activation of pro-inflammatory metabolic pathways. These findings suggest that oral microbial dysbiosis is a shared feature in hypertensive and periodontitis patients. The specific enrichment of Streptococcus sp. I-G5 in hypertension alone may indicate a potential microbial signature for this condition, contributing to a better understanding of the oral microbiome’s role in hypertension.