Rothia mucilaginosa alleviates constipation through gut microbiota remodeling and neuroactive pathway activation

BACKGROUND: Constipation affects approximately 15% of the global population, and gut microbiota dysbiosis is implicated in its pathogenesis. Rothia mucilaginosa, a commensal bacterium with established anti-inflammatory properties in the respiratory tract, has not been investigated for its effects on intestinal function. This study aimed to evaluate the therapeutic potential of Rothia mucilaginosa in a constipation mouse model using multiomics approaches. METHODS: Loperamide-induced constipation C57BL/6 mice (n = 26) were treated with Rothia mucilaginosa (2 × 10⁸ CFU/day). Therapeutic effects were assessed through fecal output parameters, gut microbiota restructuring (16S rRNA sequencing), functional genomic characterization (complete genome sequencing), host molecular responses (colon transcriptomics), and metabolic changes (untargeted metabolomics). RESULTS: Rothia mucilaginosa intervention significantly improved fecal output in constipated mice. 16S rRNA sequencing revealed enrichment of beneficial bacteria including Akkermansia muciniphila and Alistipes finegoldii, while reducing pathobionts such as Escherichia coli. Genome analysis identified 194 functional genes related to short-chain fatty acid metabolism, vitamin biosynthesis, and gut colonization. Transcriptomic analysis revealed significant enrichment of the Neuroactive ligand-receptor interaction pathway with serotonin receptor Htr1b upregulation. Untargeted metabolomics identified 170 differential metabolites between intervention and model groups. CONCLUSIONS: Rothia mucilaginosa alleviates constipation through beneficial microbiota remodeling and neuroactive pathway activation, supporting its potential as a candidate probiotic for clinical investigation.