Maternal Salivary Microbiome at 2-Months Postpartum Influences Childhood Caries

Objectives: Early childhood caries (ECC) affects ~ 48% of children globally. We hypothesized an association between presence of bacteria – previously identified as associated with caries-free and caries-active teeth – in the mother’s oral cavity at 2 months postpartum and the likelihood their child developed caries by age 5.
Methods: We analyzed the oral microbiome of mothers at 2-months postpartum, whose children were included in a previously published incidence density-matched case-control subset (53 case and 56 control pairs ) from the Center for Oral Health Research in Appalachia 2 (COHRA2) cohort. Children were followed from 2-months to age 5. Maternal saliva was amplicon sequenced using the V4 region of 16S rRNA gene, processed using DADA2, assigned taxonomy (Human Oral Microbiome Database), and relative abundance of bacterial species calculated using “phyloseq” R package (version 1.4.8). A series of linear regression models were fitted to predict the log transformed relative abundance of selected bacterial species in the mother by child’s ECC status. Species were previously identified as associated with caries.
Results: ECC status was positively associated with increased relative abundance of: Prevotella denticola (estimate=0.6972; p=0.046), Fusobacterium nucleatum subsp. vincentii (estimate=1.008; p=0.011), Corynebacterium matruchotii (estimate=0.359, p=0.093) and Rothia dentocariosa (estimate=0.305,p=0.245). ECC status was negatively associated with the relative abundance of : Lachnoanaerobaculum umeaense (estimate= -0.5192; p=0.036), and Prevotella melaninogenica (-0.875, p=0.021). There was no association with Veillonella dispar or parvula.
Conclusions: Poor maternal oral health was previously associated with children’s risk of ECC. This is a first report suggesting that specific bacterial species found in maternal saliva at 2-months postpartum may influence the risk of ECC in their children by age 5.