<i>Lactobacillus johnsonii</i> is a dominant <i>Lactobacillus</i> in the murine oral mucosa and has chitinase activity that compromises fungal cell wall integrity

The interactions between the opportunistic pathogen <i>Candida albicans</i> and resident oral bacteria are particularly crucial in maintaining oral health. Emerging antifungal drug-resistant strains, slow-paced drug discovery, and the risk of side effects can compromise the effectiveness of current treatments available for oropharyngeal candidiasis. This study advances the search for alternative microbiome-targeted therapies in oral fungal infections. We report that <i>Lactobacillus johnsonii</i> strain MT4 prevents the <i>Candida</i>-induced bloom of dysbiotic oral enterococci and reduces oral mucosal lesions in an oropharyngeal candidiasis murine model. We also show that this strain directly compromises the cell wall and reduces fungal metabolic activity, partly due to its chitinase activity.