Tongue-Coating Microbial and Metabolic Characteristics in Halitosis.

This article focuses on characterizing the tongue-coating microbiome and metabolome in individuals with intraoral halitosis (IOH) without other oral diseases, using metagenomics and metabolomics analyses. The study found that halitosis patients exhibited significantly higher microbial richness and diversity, with increased abundance of species from Actinomyces, Prevotella, Veillonella, and Solobacterium, alongside enriched metabolic pathways related to cysteine and methionine metabolism, which are linked to volatile sulfur compound (VSC) production. Functional genes involved in sulfur and indole metabolism were more abundant in halitosis samples, and metabolites such as indole-3-acetic acid and L-tryptophan were elevated and correlated with VSC levels. Machine learning models identified specific microbial species and metabolites that effectively distinguished halitosis patients from healthy controls, suggesting potential etiological roles of these microbiome and metabolome shifts in halitosis pathogenesis.