The prevalence of obesity is continually rising worldwide, posing a risk for the development of various serious diseases. The pathogenesis of obesity is complex and recent research suggests a link between obesity and the oral microbiome, though the specific mechanisms remain unclear.

We collected saliva samples from 9 non-obese and 13 obese participants and conducted 16S rRNA sequencing to analyze the differences in oral microbiota between obese and non-obese individuals in terms of microbial abundance, functionality, and interaction networks.

Obese participants exhibited a distinct composition of salivary microbiota compared to non-obese participants, with a greater number of ASVs detected and higher α diversity indices. Specifically, Haemophilus, Aggregatibacter, and Actinobacillus were significantly enriched, while Actinomyces showed significant depletion. Functional prediction analysis indicated that biofilm formation pathways were significantly more abundant in the obese group. Random forest regression model analysis identified Bergeyella as the most contributive genus, and interaction network analysis suggested that Bergeyella may function as a bridge node, linking the obese group-enriched genera to the broader microbial community and facilitating the exchange of information and resources.

Our study suggests that obesity may be closely associated with salivary microbiota dysbiosis and functional changes. Further research is needed to elucidate the causal relationship and underlying molecular mechanisms between obesity and oral microbiota dysbiosis, or to determine if they mutually influence each other.