L. reuteri DSM 17938 in Infant Nutrition and Its Impact on the Gut Microbiota of Infants Born by Cesarean Section

Introduction

The gut microbiota in newborns is highly unstable and can be influenced by various factors including the mode of delivery and type of infant nutrition. Newborns and infants born by cesarean section, unlike those born vaginally, exhibit changes in microbiota composition, which can for example result in a higher risk of developing diseases related to immune system dysfunction. In early life, the microbiota is highly susceptible to modulation by probiotics, especially in children born by cesarean section.

Study Population and Course

The study included children from a large multicenter randomized double-blind controlled trial that investigated the impact of nutrition with L. reuteri DSM 17938 on the production of D-lactate. Full-term newborns delivered either vaginally or by cesarean section were selected and given either standard infant formula or formula enriched with L. reuteri after birth. The newborns were thus divided into four groups: the CCt group consisted of those born by cesarean section and fed standard formula (n = 10), the VCt group included vaginally born infants with the same formula (n = 10); infants fed formula containing L. reuteri were also subdivided based on delivery mode – those born by cesarean were in the CLr group (n = 11) and those born vaginally in the VLr group (n = 9).

The infant formula with L. reuteri contained 1.2 × 10⁹ CFU per liter, while the control formula without L. reuteri had an identical composition apart from the absence of this probiotic. Stool samples were collected from all children at two weeks and four months of age, and microbial DNA was analyzed.

The study aimed to assess the safety profile of the formula with L. reuteri and evaluate the gut microbiota composition in each group.

Findings

Phylogenetic profiles of the microbiota in the CLr, VCt, and VLr groups showed no significant differences at two weeks or four months of age, but the microbiota composition in the CCt group differed at two weeks of age. At that time, the CLr group had significantly more actinobacteria than the CCt group (25.4 vs. 0.5%; p = 0.015). Bifidobacteria were undetectable in 50% of the CCt group, whereas they were found in 91% of the CLr group.

Compared to the VCt group, the CCt group had lower levels of bifidobacteria and higher levels of Enterobacter, Enterococcus, and Clostridium. At four months, the CCt group again showed higher levels of Enterococcus and also Coprococcus, while having lower levels of Collinsella.

In the VLr group, the gut microbiota showed a higher presence of lactobacilli (at two weeks) and Coprococcus (at four months) compared to the VCt group. More lactobacilli were also present in the CLr group compared to the CCt group, both at two weeks and four months.

Conclusion

Infants fed formula containing L. reuteri DSM 17938 showed a higher presence of this probiotic, regardless of age or mode of delivery. The results further indicate that such a formula plays an important role in shaping the microbiota of cesarean-delivered infants, potentially aligning it more closely with the commonly observed microbiota in vaginally born infants. The microbiota of cesarean-delivered infants exhibits several deviations from the usual neonatal microbiota composition; the significant modulatory potential of L. reuteri can be explained by the absence of certain bacterial genera that the newborn would acquire during vaginal delivery.

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Source: Garcia Rodenas C. L., Lepage M., Ngom-Bru C. et al. Effect of formula containing Lactobacillus reuteri DSM 17938 on fecal microbiota of infants born by cesarean section. J Pediatr Gastroenterol Nutr 2016; 63 (6): 681–687, doi: 10.1097/MPG.0000000000001198.