Restraint of dental caries-inducing Streptococcus mutans MTCC497 by potential oral bacterial metabolite - In vitro and In vivo analysis in Caenorhabditis elegans.

Excessive consumption of sucrose by humans often leads to dental caries, primarily induced by the bacterium Streptococcus mutans. This bacterium utilizes glucosyltransferase to break down sugar into glucose, resulting in the synthesis of sticky glucan, which promotes caries formation. However, some individuals display resistance to caries due to the prevalence of other oral bacteria with inhibitory properties against S. mutans. This study aims to extract effective bacterial metabolites from isolated oral bacteria found in the microbiota of healthy individuals. These metabolites were selected based on their antagonistic activity against S. mutans and subjected to probiotic screening tests. Whole cell metabolites were extracted, and the most promising bacteria were then evaluated for glucosyltransferase enzyme inhibition activities against caries-inducing pathogen. The toxicity of the identified oral bacterial metabolite was tested with Caenorhabditis elegans. Among the tested oral bacterial metabolites, the metabolite of the bacteria DMTMMLMH801 exhibited significant inhibition against the pathogen. High Content Screening imaging revealed no toxicity in synchronized C. elegans treated with MIC level of the metabolite. This conclusion was drawn following biochemical characterization and 16S rRNA sequencing revealed that the bacteria DMTMMLMH801 belongs to a lineage closely related to the novel bacterium Enterobacter quasihormaechei, suggesting its potential as a novel candidate for combating dental caries.