Saadaoui Marwa, Djekidel Mohamed Nadhir, Murugesan Selvasankar, Kumar Manoj, Elhag Duaa, Singh Parul, Kabeer Basirudeen Syed Ahamed, Marr Alexandra Katharina, Kino Tomoshige, Brummaier Tobias, McGready Rose, Nosten François, Chaussabel Damien, Terranegra Annalisa, Al Khodor Souhaila
Research Department, Sidra Medicine, Doha, Qatar.
Center for Global Health Research, Saveetha Medical College and Hospital, Saveetha University, Chennai, India.
Front Cell Infect Microbiol. 2025 Jan 16;14:1486409. doi: 10.3389/fcimb.2024.1486409. eCollection 2024.
For years, the placenta was believed to be sterile, but recent studies reveal it hosts a unique microbiome. Despite these findings, significant questions remain about the origins of the placental microbiome and its effects on pregnancy and fetal health. Some studies suggest it may originate from the vaginal tract, while others indicate that oral bacteria can enter the maternal bloodstream and seed the placenta. However, research analyzing the vaginal, oral, and placental microbiomes within the same cohort is lacking. Additionally, it's unclear whether the placental microbiome differs between healthy pregnancies and those with complications like preterm birth (PTB), which remains a leading cause of neonatal morbidity and mortality worldwide.
In this study, we performed 16S rRNA gene sequencing to investigate the composition of the oral and placental microbiome in samples collected from 18 women who experienced PTB and 36 matched controls who delivered at term (TB), all of whom were part of the Molecular Signature in Pregnancy (MSP) study. We leveraged on the multisite microbiome sampling from the MSP participants and on our previously published vaginal microbiome data to investigate the potential origins of the placental microbiome and assess whether its composition varies between healthy and complicated pregnancies.
Our analysis revealed distinct profiles in the oral microbiome of PTB subjects compared to those who delivered at term. Specifically, we observed an increased abundance of Treponema maltophilum, Bacteroides sp, Mollicutes, Prevotella buccae, Leptotrichia, Prevotella_sp_Alloprevotella, in the PTB group. Importantly, Treponema maltophilum species showed higher abundance in the PTB group during the second trimester, suggesting its potential use as biomarkers. When we assessed the placenta microbiome composition, we found that Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria were the most dominant phyla. Interestingly, microorganisms such as Ureaplasma urealyticum were more abundant in PTB placenta samples. Our findings suggest that the placenta microbiome could originate from the oral or vaginal cavities, with a notable increase in the crosstalk between the vaginal and placental sites in cases of PTB. Specifically, our data revealed that in PTB cases, the placental microbiome exhibited a closer resemblance to the vaginal microbiome, whereas in term pregnancies, the placental microbiome was similar to the oral microbiome.
多年来，人们一直认为胎盘是无菌的，但最近的研究表明它拥有独特的微生物群。尽管有这些发现，但关于胎盘微生物群的起源及其对妊娠和胎儿健康的影响仍存在重大疑问。一些研究表明它可能起源于阴道，而另一些研究则表明口腔细菌可进入母体血液循环并定植于胎盘。然而，缺乏对同一队列中的阴道、口腔和胎盘微生物群进行分析的研究。此外，尚不清楚健康妊娠与早产（PTB）等并发症妊娠的胎盘微生物群是否存在差异，早产仍是全球新生儿发病和死亡的主要原因。
在本研究中，我们对18例早产女性和36例足月分娩（TB）的匹配对照者所采集样本中的口腔和胎盘微生物群组成进行了16S rRNA基因测序，所有这些人均为妊娠分子特征（MSP）研究的一部分。我们利用MSP参与者的多部位微生物群样本以及我们之前发表的阴道微生物群数据，来研究胎盘微生物群的潜在起源，并评估其组成在健康妊娠和复杂妊娠之间是否存在差异。
我们的分析显示，与足月分娩者相比，早产受试者的口腔微生物群具有不同的特征。具体而言，我们观察到在早产组中嗜麦芽寡养单胞菌、拟杆菌属、柔膜菌纲、颊普雷沃菌、纤毛菌属、普雷沃菌属_别普雷沃菌属的丰度增加。重要的是，嗜麦芽寡养单胞菌在孕中期的早产组中丰度更高，表明其有可能用作生物标志物。当我们评估胎盘微生物群组成时，发现厚壁菌门、拟杆菌门、放线菌门和变形菌门是最主要的门类。有趣的是，解脲脲原体等微生物在早产胎盘样本中更为丰富。我们的研究结果表明，胎盘微生物群可能起源于口腔或阴道，在早产情况下，阴道和胎盘部位之间的相互作用显著增加。具体而言，我们的数据显示，在早产病例中，胎盘微生物群与阴道微生物群更为相似，而在足月妊娠中，胎盘微生物群与口腔微生物群相似。
