Impact du mode d'accouchement sur l'établissement et la diversité du microbiote intestinal chez les nourrissons

Abstract

The infant gut microbiota plays a fundamental role in immune development, digestion, and metabolic balance. Its early establishment is influenced by several factors, foremost among them the mode of delivery. This study aims to evaluate the impact of delivery mode (vaginal birth vs. cesarean section) on the establishment and diversity of the intestinal microbiota in newborns. Our study involved six newborns, three delivered vaginally and three by cesarean section. Fecal samples were collected on days 1 and 10 of life and analyzed using culture on selective media. Results show that vaginally delivered newborns exhibit early colonization from day one by beneficial bacteria of the genera Streptococcus, Enterococcus, Lactobacillus, and Escherichia coli. By day ten, their flora evolves towards a dominance of Bifidobacteria and lactobacilli, typical of a protective microbiota, especially in breastfed infants.In contrast, cesarean-born newborns have an initially depleted microbiota dominated by skin- or hospital- derived bacteria belonging to the genera Staphylococcus and Streptococcus. Cesarean delivery may thus contribute to neonatal dysbiosis, with potential long-term health implications. Strategies such as breastfeeding, probiotic use, or vaginal seeding could help mitigate these effects.