Extremely preterm neonates have more Lactobacillus in meconium than very preterm neonates – the in utero microbial colonization hypothesis

Abstract

Growing evidence suggests that maternal microbiota can influence the neonates' gut colonization. However, the mechanisms of vertical bacterial transmission remain poorly defined. We believed that the first colonizers of the newborn come from the mother's gut and vagina during pregnancy and that this is independent of the mode of delivery. We conducted an observational longitudinal study to evaluate the link between the maternal gut microbiota and the meconium's microbiota in extremely and very preterm neonates. Bacterial DNA was extracted from samples and specific bacterial groups were quantified by RT-PCR. In this cohort of 117 preterm neonates, we detected bacterial DNA in 88% of meconium samples. Meconium microbiota of neonates born after 28 gestational weeks (very preterm neonates) showed stronger correlations with their mothers' fecal microbiota. However, neonates born before 28 gestational weeks (extremely preterm neonates) had more Lactobacillusgenus that dominated the vaginal microbiota-than very preterm neonates, regardless of the mode of delivery. Collectively, these data support the hypothesis that maternal bacteria from the gut and vagina can play a role in shaping neonates' gut microbiota and that mother-to-infant bacterial transmission is a controlled and time-specific process. ClinicalTrials.gov Identifier: NCT03663556 ARTICLE HISTORY

A systematic review of the factors influencing microbial colonization of the preterm infant gut

“…The prevailing paradigm in obstetrics has been the sterile womb hypothesis. However, studies have identified the presence of bacteria in the amniotic fluid, placenta, umbilical cord, 91 , 92 and meconium of PT, 93 and full-term infants. 94 This suggests that colonization of the gastrointestinal tract begins in utero .…”

Influence of Human Milk on Very Preterms’ Gut Microbiota and Alkaline Phosphatase Activity

“…Microbiota results are expressed as log10 16S rRNA gene copies/10 ng of DNA. All of the analyses were conducted using the appropriate negative controls, as previously described [ 21 ].…”

First 1000 Days and Beyond After Birth: Gut Microbiota and Necrotizing Enterocolitis in Preterm Infants

“…Although the idea of whether the prenatal environment is sterile remains questionable (Fricke and Ravel, 2021), the presence of microbiota has been detected in meconium by using either nextgeneration sequencing (NGS) or real-time PCR (Morais et al, 2020;Hiltunen et al, 2021;Klopp et al, 2022). The meconium FIGURE 1 | The developmental trajectory and comparisons of full-term and preterm infants in the first 1000 days after birth.…”

“…Although the idea of whether the prenatal environment is sterile remains questionable ( Fricke and Ravel, 2021 ), the presence of microbiota has been detected in meconium by using either next-generation sequencing (NGS) or real-time PCR ( Morais et al, 2020 ; Hiltunen et al, 2021 ; Klopp et al, 2022 ). The meconium microbiota normally exhibits large between-individual variation, which is influenced by gestational age at birth ( Klopp et al, 2022 ).…”