Fucosylated oligosaccharides in mother\u2019s milk alleviate the effects of caesarean birth on infant gut microbiota

Kaarina Kukkonen,Katri Korpela,Mikael Kuitunen,Norbert Sprenger,Clemens Kunz,Anne Salonen,Willem M De Vos,Erkki Savilahti,Brandon Hickman

doi:10.1038/s41598-018-32037-6

Abstract

One of the most abundant components in human milk is formed by oligosaccharides, which are poorly digested by the infant. The oligosaccharide composition of breast milk varies between mothers, and is dependent on maternal secretor (FUT2) genotype. Secretor mothers produce milk containing α1-2 fucosylated human milk oligosaccharides, which are absent in the milk of non-secretor mothers. Several strains of bacteria in the infant gut have the capacity to utilise human milk oligosaccharides (HMOs). Here we investigate the differences in infant gut microbiota composition between secretor (N = 76) and non-secretor (N = 15) mothers, taking into account birth mode. In the vaginally born infants, maternal secretor status was not associated with microbiota composition. In the caesarean-born, however, many of the caesarean-associated microbiota patterns were more pronounced among the infants of non-secretor mothers compared to those of secretor mothers. Particularly bifidobacteria were strongly depleted and enterococci increased among the caesarean-born infants of non-secretor mothers. Furthermore, Akkermansia was increased in the section-born infants of secretor mothers, supporting the suggestion that this organism may degrade HMOs. The results indicate that maternal secretor status may be particularly influential in infants with compromised microbiota development, and that these infants could benefit from corrective supplementation.

Highlights

Infants are adapted to obtaining all of their nutrition from human milk during the first months of life
The reduction in bifidobacteria was largely due to the absence of Bifidobacterium bifidum and B. breve (Fig. 3A), while the increase in enterococci was attributable to a bloom of Enterococcus lactis and two uncultured Enterococcus species; Enterococcus faecium levels were comparable (Fig. 3B)
Our results indicate that infants of non-secretor mothers are vulnerable to the effects of caesarean section on the early microbiota development

Summary

Introduction

Infants are adapted to obtaining all of their nutrition from human milk during the first months of life. In addition to nutrients for the infant, breast milk contains a diverse mixture of complex oligosaccharides, termed human milk oligosaccharides (HMOs), at an abundance of approximately 10 g/l1. These oligosaccharides are poorly digested by the infant, but are favoured growth substrates for intestinal bacteria that have the appropriate enzymatic degradation capacity. The α1-2 fucosylated oligosaccharides are degraded by enzymes of the glycosyl hydrolase family 95, possessed by strains of bifidobacteria commonly observed in infants (strains of B. longum infants, B. bifidum, B. breve) as well as Bacteroides spp.[9,10,11,12,13] The abundance of these bacteria is associated with birth mode, being commonly reduced in caesarean-born infants[14]. We investigate the differences in infant gut microbiota composition between secretor and non-secretor mothers, taking into account birth mode

Methods

Results

Conclusion