The maternal microbiome in pregnancy, delivery, and early-stage development of neonatal microbiome after cesarean section: A prospective longitudinal study.

INTRODUCTION: Changes within the maternal microbiome during the last trimester of pregnancy and the determinants of the subsequent neonatal microbiome establishment after delivery by elective cesarean section are described. MATERIAL AND METHODS: Maternal vaginal and rectal microbiome samples were collected in the last trimester and before cesarean section; intrauterine cavity, placenta, neonatal buccal mucosa, skin, and meconium samples were obtained at birth; neonatal sample collection was repeated 2-3 days postnatally. Microbial community composition was analyzed by 16S rRNA gene amplicon sequencing. Relative abundance measurements of amplicon sequencing variants and sum counts at higher taxonomic levels were compared to test for significant overlap or differences in microbial community compositions. CLINICALTRIALS: gov ID: NCT04489056. RESULTS: A total of 30 mothers and their neonates were included with available microbiome samples for all maternal, intrauterine cavity and placenta samples, as well as for 18 of 30 neonates. The composition of maternal vaginal and rectal microbiomes during the last trimester of healthy pregnancies did not significantly change (permutational multivariate analysis of variance [PERMANOVA], p > 0.05). No robust microbial signature was detected in the intrauterine cavity, placenta, neonatal buccal mucosa, skin swabs, or meconium samples collected at birth. After birth, the neonatal microbiome was rapidly established, and significantly different microbial communities were detectable 2-3 days postnatally in neonate buccal mucosa and stool samples (PERMANOVA, p < 0.01). CONCLUSIONS: Maternal vaginal and rectal microbiomes in healthy pregnancies remain stable during the third trimester. No microbial colonization of the neonate was observed before birth in healthy pregnancies. Neonatal microbiomes in infants delivered by cesarean section displayed a taxonomic composition distinct from maternal vaginal and rectal microbiomes at birth, indicating that postnatal exposure to the extrauterine environment is the driving source of initial neonatal microbiome development in this cohort.

Vaginal Microbial Colonization after Antibiotic Treatment in Women with Preterm Premature Rupture of Membranes: An Observational Cohort Study.

Preterm premature rupture of membranes (pPROM) stands as a primary contributor to preterm deliveries worldwide, closely linked to consequential infectious peripartum complications, including chorioamnionitis and early-onset neonatal sepsis. As a prophylactic measure, individuals following pPROM routinely undergo antibiotic treatment. The aim of this study was to evaluate changes in the vaginal microbial colonization after antibiotic treatment following pPROM. Therefore, we retrospectively assessed the impact of antibiotic treatment on the maternal vaginal microbial colonization in 438 post-pPROM patients delivering before 29 gestational weeks. Vaginal samples were collected for microbiological analysis before and after antibiotic administration and analysed for seventeen pre-defined microbial groups. We observed eradication in eleven microbial groups, including beta-hemolytic streptococci group B and Gardnerella vaginalis. No significant reduction was found for the remaining groups, including Escherichia (E.) coli. Moreover, we found a notable increase in resistant bacteria after antibiotic treatment. In conclusion, broad-spectrum antimicrobial treatment exhibited substantial efficacy in eradicating the majority of pathogens in our cohort. However, certain pathogens, notably E. coli, showed resilience. Given E. coli's prominent role in infectious peripartum complications, our findings underline the challenges in antibiotic management post-pPROM and the need to establish international guidelines, particularly regarding emerging concerns about antibiotic resistances.