Salivary Microbiome in Children With Down Syndrome

Down syndrome (DS), a most frequently occurring genetic disorder, is associated with oral morphological abnormalities and higher incidence rates of oral diseases. Recent studies have analyzed the oral microbiome to elucidate their relationships with oral diseases and general health; however, reports on the oral microbiome in individuals with DS are scarce. This study aimed to characterize the oral microbiome in children with DS. The salivary microbiomes of children with DS (DS) and children without DS (ND) aged 1 to 12 years were compared. Results of culture and quantitative polymerase chain reaction (qPCR) detection tests for cariogenic and periodontopathic bacteria showed no significant differences in the detected bacteria between the DS and ND groups, with the exception of a significantly higher detection rate of Candida albicans in children with DS with mixed dentition. A comparison of the salivary microbiomes by 16S sequencing showed no significant difference in α diversity; however, it showed a significant difference in β diversity. Children with DS had a higher relative abundance of Corynebacterium and Cardiobacterium , and lower relative abundance of TM7. This study provided basic data on the salivary microbiome of children with DS and further identified a characteristic microbiological marker of children with DS.