Ethnicity-specific microbiome in early childhood caries: from the functional perspectives of oral biofilm

National surveillance data has long shown a significant disparity in tooth decay among young children (early childhood caries, ECC). While factors including household poverty level, culture, health insurance, and infrastructure have been studied, the biomedical perspective is less explored. Using RNASeq technology, our findings show that, besides Streptococcus mutans , which is most commonly associated with caries, several additional dental plaque bacteria are significantly overexpressed in caries lesions. Notably, the bacterial species and functional profiles differ markedly between African American and Latin American Hispanic children. In African American children, gene expression profiles linked to Pseudopropionibacterium propionicum and Cardiobacterium hominis ; in contrast, in Latin American Hispanic children, gene expression profiles were dominated by Propionibacterium acidifaciens , Selenomonas sp. , Rothia dentocariosa , Atopobium parvulum , and Streptococcus sanguinis . This study underscores the diverse metabolic pathways in plaque bacteria contributing to ECC in minority populations, identifying significant bacterial species beyond common cariogenic bacteria. Main Text: