Plaque sample from patients diagnosed with adult severe caries and healthy individuals without caries
The composition and its interactions of oral microbiota play important role in the development of dental caries. As adult severe caries brings great oral dysfunction and treatment difficulties to patients and have not yet found a clear pathogenic mechanism. This study aimed to investigated the dental plaque microbiome profiles (bacterial and fungal profiles) in control and adult severe caries to identify disease-relevant species. Samples of dental plaque from adult severe caries patients and caries free werecollected (n = 13, 7 adult severe caries patients and 6 caries free) for metagenomic analysis. Six species (Streptococcus mutans, Veillonella parvula, Veillonella dispar, Veillonella sp, Bacteroides xylanisolvens and Salmonella enterica) were found association with adult severe caries.The most abundant significantly mutative taxonomy was V. parvula. Using multiscale/computational imaging and virulence assays, we examined the inter-species interaction between V. parvula and S. mutans. We showed that V. parvula can effectively promote S. mutans mature biofilm formation with enhanced acid resistance, hydrogen peroxide detoxicity and biofilm virulence and is mainly attributed to the boost of the adhesion,coaggregation, growth and extracellular exopolysaccharide(EPS) synthesis of S. mutans. Rodent model experiments revealed in uncapable of causing disease on its own, V. parvula significantly heightened the biofilm virulence of S.mutans in vivo when co-infected and augmented the progression, quantity and severity of dental caries. In summary, Our findings demonstrated that V. parvula may act as a synergistic pathobiont to modulate the metabolic activity of S. mutans, spatial structure and pathogenicity of biofilms of S. mutans in the context of adult severe caries disease.