Comparison of the oral microbiota of children with autism spectrum disorder in primary dentition with neurotypical controls

Abstract

Background: The number of studies suggesting differences in oral microbiota in autism spectrum disorders (ASDs) is increasing. However, the relationship between oral microbiota and ASD has not been determined. Therefore, this study aimed to examine the oral microbiota of children with ASD compared with neurotypical controls. Method: Nine boys with a diagnosis of ASD according to the Diagnostic and Statistical Manual of the American Psychiatric Association, Fifth Edition who were aged 36 to 60 months (44 +/- 6.34), and nine neurotypical age-matched boys were included in the study. After detailed clinical examinations, saliva samples were collected. DNA from the samples was investigated by highthroughput sequencing of the 16S rRNA gene. The Childhood Autism Rating Scale was used to assess the severity of ASD in the case group. Results: An analysis of alpha and beta diversity indexes and principal coordinate analysis revealed no significant differences between ASD and neurotypical controls nor were there significant differences in the relative abundance of the phyla and genera between the two groups. However, the distribution of operational taxonomic units (with a relative abundance> 1 %) for Bacillales, Granulicatella elegans, Micrococcaceae, Micrococcales, Neisseria zalophi, S. anginosus SK52 = DSM 2563, S. cristatus AS 1.389, S. mitis, S. oralis subsp. dentisani and S. pneumoniae were significantly higher in the ASD group (p < 0.05). Conclusions: Differences in the relative abundance of some taxa in the saliva of children with ASD compared with neurotypical controls were found. Further studies are needed to understand the relationship between oral microbiota and ASD.