A Higher Abundance of Actinomyces spp. in the Gut Is Associated with Spontaneous Preterm Birth

Abstract

Preterm birth is a major challenge in pregnancy worldwide. Prematurity is the leading cause of death in infants and may result in severe complications. Nearly half of preterm births are spontaneous, but do not have recognizable causes. This study investigated whether the maternal gut microbiome and associated functional pathways might play a key role in spontaneous preterm birth (sPTB). Two hundred eleven women carrying singleton pregnancies were enrolled in this mother-child cohort study. Fecal samples were freshly collected at 24–28 weeks of gestation before delivery, and the 16S ribosomal RNA gene was sequenced. Microbial diversity and composition, core microbiome, and associated functional pathways were then statistically analyzed. Demographic characteristics were collected using records from the Medical Birth Registry and questionnaires. The result showed that the gut microbiome of mothers with over-weight (BMI ≥ 24) before pregnancy have lower alpha diversity than those with normal BMI before pregnancy. A higher abundance of Actinomyces spp. was filtered out from the Linear discriminant analysis (LDA) effect size (LEfSe), Spearman correlation, and random forest model, and was inversely correlated with gestational age in sPTB. The multivariate regression model showed that the odds ratio of premature delivery was 3.274 [95% confidence interval (CI): 1.349; p = 0.010] in the group with over-weight before pregnancy with a cutoff Hit% > 0.022 for Actinomyces spp. The enrichment of Actinomyces spp. was negatively correlated with glycan biosynthesis and metabolism in sPTB by prediction from the Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) platform. Maternal gut microbiota showing a lower alpha diversity, increased abundance of Actinomyces spp., and dysregulated glycan metabolism may be associated with sPTB risk.

Unveiling the dynamics of the breast milk microbiome: impact of lactation stage and gestational age

“…Streptococcus was the predominant genera in our preterm BM samples, whereas the abundance of Staphylococcus was lower than previously reported [ 21 ]. In a case–control study examining the gut microbiota of 121 mothers with vaginal deliveries, the mothers giving birth prematurely were found to have lower abundance of Streptococcus , four days postpartum [ 82 ], whereas another study reported a higher abundance of Streptococcus in the gut microbiota of mothers who deliver preterm before delivery [ 83 ]. Evidence also suggests that PTB is associated with maternal Group B Streptococcus (GBS) colonization worldwide, previous work from SMRU suggests a low proportion (12%) of mothers carry Group B Streptococcus at birth [ 84 , 85 ].…”

Stress and depression-associated shifts in gut microbiota: A pilot study of human pregnancy

“…Interestingly, increased abundance of Actinomyces have been reported in those with depression, Crohn’s disease, and SARS-CoV-2 infections ( Barandouzi et al, 2020 ; Farsi et al, 2022 ; Pittayanon et al, 2020 ). During pregnancy, Actinomyces infections appear to be rare, but increased abundance of Actinomyces species is associated with increased risk of spontaneous preterm birth ( Yu et al, 2023 ). Therefore, our results contrast with the extant literature reporting Actinomyces .…”