Gut microbiota comparison of vaginally and cesarean born infants exclusively breastfed by mothers secreting α1–2 fucosylated oligosaccharides in breast milk

Background: Exclusive breastfeeding promotes beneficial modifications on the microbiota of cesarean born infants, but little is known about the role of specific breast milk components in this modulation. Women with an active FUT2 gene (called secretors) secrete α1–2 fucosylated human milk oligosaccharides (HMOs), which promote Bifidobacterium in the infant’s gut and may modulate the microbiota of cesarean born infants. Objective: To compare the microbiota composition of cesarean and vaginally born infants breastfed by secretor mothers. Methods: Maternal secretor status was determined by the occurrence of 4 different α1–2 fucosylated HMOs in breast milk by LC-MS. The fecal microbiota composition from cesarean and vaginally born infants was analyzed by 16S rRNA gene sequencing and qPCR, stratified by the maternal secretor status, and compared. Results: Alpha and beta diversity were not significantly different in cesarean born, secretor-fed infants (CSe+) compared to vaginally born, secretor-fed infants (VSe+). There were no significant differences in the fecal relative abundance of Bifidobacterium between CSe+ and VSe+ infants, but the prevalence of the species B. longum was lower in CSe+. The fecal relative abundance of Bacteroides was also lower, while Akkermansia and Kluyvera were higher in CSe+ infants. Conclusion: Cesarean and vaginally born infants fed with breast milk containing the α1–2 fucosylated HMOs fraction present similar amounts of Bifidobacterium in the feces, but differences are observed in other members of the microbiota.