Effect of probiotics and breastfeeding on the bifidobacterium and lactobacillus/enterococcus microbiota and humoral immune responses.

OBJECTIVE: To assess impact of probiotics and breastfeeding on gut microecology. STUDY DESIGN: Mothers were randomized to receive placebo or Lactobacillus rhamnosus GG before delivery, with treatment of the infants after delivery. We assessed gut microbiota, humoral immune responses, and measured soluble cluster of differentiation 14 (sCD14) in colostrum in 96 infants. RESULTS: Fecal Bifidobacterium and Lactobacillus/Enterococcus counts were higher in breastfed than formula-fed infants at 6 months; P <.0001 and P=.01, respectively. At 3 months, total number of immunoglobulin (Ig)G-secreting cells in breastfed infants supplemented with probiotics exceeded those in breastfed infants receiving placebo; P=.05, and their number correlated with concentration of sCD14 in colostrum. Total numbers of IgM-, IgA-, and IgG-secreting cells at 12 months were higher in infants breastfed exclusively for at least for 3 months and supplemented with probiotics as compared with breastfed infants receiving placebo; P=.005, P=.03 and P=.04, respectively. Again, sCD14 in colostrum correlated with numbers of IgM and IgA cells; P=.05 in both. CONCLUSIONS: We found an interaction between probiotics and breastfeeding on number of Ig-secreting cells, suggesting that probiotics during breastfeeding may positively influence gut immunity.