Background: The origin of the initial oral microbiota in neonates still remains poorly understood.

Objective: The aim of this study was to understand how the maternal microbiota contributes to the initial neonatal oral microbiota.

Design: Twelve mother-neonate pairs with samples from the maternal oral mucosa, uterine cervix and placenta and the neonatal oral cavity immediately after birth were studied. The microbiota composition and diversity were characterized by 16S rRNA gene sequencing (V3-V4 region). The microbiota analyses and comparisons were carried out with Calypso software version 8.1 and with SourceTracker 1.0.1.

Results: Samples from the neonatal oral cavity showed moderately high bacterial diversity and low richness. The neonatal oral cavity microbiota seems to share features mainly with the microbes detected in the placenta, followed by the cervical microbiota and the maternal oral microbiota. No statistically significant differences in diversity (Shannon index, p = 0.14), richness (Chao1, p = 0.53) or in microbial composition were observed according to delivery mode.

Conclusion: The neonatal oral cavity microbiota is not significantly modulated by the birth canal or maternal oral microbiota but displays clear associations with microbes in the placenta. These results suggest that the neonatal oral microbiota may have a prenatal origin.

背景：新生儿最初口腔微生物群的起源仍然知之甚少。

目的：本研究的目的是了解母体微生物群如何促进最初的新生儿口腔微生物群。

设计：研究了十二对母亲-新生儿，并从出生后立即收集了来自母亲口腔粘膜，宫颈和胎盘以及新生儿口腔的样品。通过16S rRNA基因测序（V3-V4区）对微生物群组成和多样性进行了表征。微生物群的分析和比较是使用Calypso软件版本8.1和SourceTracker 1.0.1进行的。

结果：新生儿口腔样品显示中等程度的细菌多样性和低丰度。新生儿口腔微生物群似乎与胎盘中检测到的微生物具有共同的特征，其次是宫颈微生物群和孕妇口腔微生物群。根据输送方式，在多样性（香农指数，p = 0.14），丰富度（Chao1，p = 0.53）或微生物组成方面均未观察到统计学上的显着差异。

结论：新生儿口腔微生物区系不受产道或母亲口腔微生物区系的显着调节，但与胎盘中的微生物具有明显的关联。这些结果表明，新生儿口腔微生物群可能具有产前起源。