Impact of Bifidobacterium lactis supplementation on fecal microbiota in infants delivered vaginally compared to Caesarean section

Background It has been reported that infants born by Caesarean section have altered gut microbiota, with lower numbers of bifidobacteria and Bacteroides, compared to that of infants who were delivered vaginally. Probiotic supplementation has been reported to have beneficial effects on the immune response, generally in relation to allergies. Objective To assess the effect of Bifidobacterium lactis (B. lactis) supplementation on the presence of B. lactis and bifidobacteria counts in stool of infants during the first 2 months of life. Methods We conducted an observational study of 122 healthy, breast-fed infants delivered vaginally or by Caesarean section. Infants assigned to the test group received breast milk and formula supplemented with the B. lactis probiotics. Infants in the control group received breast milk and formula without probiotics. The presence of B. lactis and stool bifidobacteria counts were determined at 1 month and 2 months of age. Growth, morbidity, serum immune markers, and stool immunoglobulin (lg) A were also assessed Results B. lactis was more frequently detected in the stool of infants who received breast milk and probiotic-supplemented formula than in stool of infants who received breast milk and non-supplemented formula, both at 1 month and 2 months of age (OR 1,263; 95%Cl 11 to 15 1,030; P=0.003) . Of infants who received probiotic-supplemented formula, B. lactis was detected in 80% of those delivered by Caesarean section and in 3 8% of those delivered vaginally, at the 1-month mark. In infants delivered by Caesarean section, the mean stool bifidobacteria level at 1 month was significantly higher in the probiotic-supplemented group compared to that of the non-supplemented group (P=0.021) . Conclusion Early bifidobacteria supplementation of infants, particularly those delivered by Caesarean section, is associated with higher levels of stool bifidobacteria. Anthropometric data suggests beneficial effect s of bifidobacteria supplementation on infant growth, though most are not statistically significant.