Perturbations to the gut microbiome are implicated in altered neurodevelopmental trajectories that may shape life span risk for emotion dysregulation and affective disorders. However, the sensitive periods during which the microbiome may influence neurodevelopment remain understudied. We investigated relationships between gut microbiome composition across infancy and temperament at 12 months of age. In 67 infants, we examined if gut microbiome composition assessed at 1–3 weeks, 2, 6, and 12 months of age was associated with temperament at age 12 months. Stool samples were sequenced using the 16S Illumina MiSeq platform. Temperament was assessed using the Infant Behavior Questionnaire-Revised (IBQ-R). Beta diversity at age 1–3 weeks was associated with surgency/extraversion at age 12 months. Bifidobacterium and Lachnospiraceae abundance at 1–3 weeks of age was positively associated with surgency/extraversion at age 12 months. Klebsiella abundance at 1–3 weeks was negatively associated with surgency/extraversion at 12 months. Concurrent composition was associated with negative affectivity at 12 months, including a positive association with Ruminococcus-1 and a negative association with Lactobacillus. Our findings support a relationship between gut microbiome composition and infant temperament. While exploratory due to the small sample size, these results point to early and late infancy as sensitive periods during which the gut microbiome may exert effects on neurodevelopment.

肠道微生物群的扰动与神经发育轨迹的改变有关，这可能会影响情绪失调和情感障碍的终生风险。然而，微生物组可能影响神经发育的敏感期仍未得到充分研究。我们研究了婴儿期肠道微生物组组成与 12 个月大时气质之间的关系。在 67 名婴儿中，我们检查了 1-3 周、2、6 和 12 个月时评估的肠道微生物组组成是否与 12 个月时的气质相关。使用 16S Illumina MiSeq 平台对粪便样本进行测序。使用婴儿行为问卷修订版（IBQ-R）评估气质。1-3 周龄时的 Beta 多样性与 12 个月龄时的手术/外向性相关。1-3周龄时双歧杆菌和毛螺菌科的丰度与12月龄时的手术/外倾呈正相关。1-3 周时的克雷伯氏菌丰度与 12 个月时的手术/外倾呈负相关。12 个月时，同时组成与负面情感相关，包括与瘤胃球菌-1呈正相关，与乳酸菌呈负相关。我们的研究结果支持肠道微生物组组成与婴儿气质之间的关系。虽然由于样本量较小而具有探索性，但这些结果表明婴儿早期和晚期是肠道微生物组可能对神经发育产生影响的敏感时期。