Niche-driven microbial architecture in mothers and newborns with minimal cohort influence across anatomically...

The microbiota plays a crucial role in the functioning of the human body. Several theories have been proposed regarding the origin of the uterine microbiota, including both ascending pathways from the vagina and translocation from the gastrointestinal tract. Numerous studies suggest that, in preterm births, amniotic fluid may contain microbial DNA or signals associated with microorganisms ascending from the vagina, even in the presence of intact fetal membranes, as well as by microbes originating from the placental microbiome.

The aim of this study was to comprehensively characterize the maternal and neonatal microbiome across multiple anatomically and biologically distinct niches and to determine the extent to which the structure of microbial communities reflects (i) anatomical location, (ii) maternal-infant relationships, and (iii) cohort-related perinatal factors.

The study included eight women who delivered between 34 + 0 and 36 + 6 weeks of gestation, along with their neonates. The control group consisted of eight women who delivered at ≥37 + 0 weeks of gestation and their neonates. Prior to delivery, a cervical swab, an oral (buccal) swab, and a stool sample were collected. After delivery, the following samples were obtained from the neonate: a skin swab, a sample of amniotic fluid aspirated from the stomach, a rectal swab, and placental tissue. To assess microbiota composition, microbiome profiling based on 16S rRNA gene sequencing was performed.

The analysis did not demonstrate significant differences in microbiota composition between late preterm and term pregnancies, in either mothers or neonates.

Comparative analysis of maternal and neonatal microbiota suggests a possible association with microbial signals consistent with an ascending vaginal contribution; however, without a detectable influence on neonatal microbiota. Conversely, the findings may indicate a potential association with maternal microbiota consistent with a hematogenous contribution, however, no direct evidence of microbial colonization or transmission can be inferred.