The tongue biofilm metatranscriptome identifies metabolic pathways associated with halitosis and its prevention

Halitosis is an oral condition caused by an increase in the concentration of volatile sulfur compounds (VSCs), mainly methyl mercaptan and hydrogen sulfide, generated as a consequence of bacterial degradation of amino acids on the tongue. Microbial communities on the tongue of halitosis patients have been studied by bacterial culture, 16S rRNA taxonomic studies and metagenomics, showing an association of several bacterial pathways to the production of VSCs. However, there are currently no reports on the microbial gene-expression profiles, which could identify the specific pathways involved in halitosis. In this study, we sequenced the RNA of tongue coating samples from control individuals and halitosis patients with different levels and composition of VSCs, as determined by gas chromatography.