Microbial exposure at birth and the development of behavioral temperament during the first three years of childhood

We investigated cross-sectional and longitudinal associations between neonate microbial exposure and emerging behavioral temperament measures at the ages of 1, 2, and 3 years. Infants and mothers (<i>n = 335</i>) were extracted from the Kuopio Birth Cohort Study. Temperament was assessed using the Infant Behavioral and Early Childhood Behavioral Questionnaires. Microbial samples were collected from oral cavity at birth and the bacterial profiles were assessed using 16S rRNA gene sequencing. Microbial diversity was characterized using alpha and beta diversity metrics. Analyses were performed for the most abundant genera. The sample was analyzed as a whole, as well as divided into subgroups representing no antibiotic use during birth (<i>n = 198</i>) and those with antibiotic use during birth (<i>n = 137</i>). No significant associations were observed between microbial profiles and behavioral measures after Bonferroni corrections. Nevertheless, our pre-correction results indicated an association between increased behavioral temperament surgency in the first year and beta diversity (high abundance of <i>Bacteroides</i>, <i>Faecalibacterium</i> and <i>Blautia</i>, low abundance of <i>Lactobacillus</i>) in the antibiotic use group. Additionally, pre-corrections, a high relative abundance of <i>Staphylococcus</i> was associated with increased surgency through years 1, 2, and 3 in the no antibiotics group, prompting consideration into a possible link between antibiotic use and emerging behavioral temperament.