Administration of oral probiotic bacteria to pregnant women causes temporary infantile colonization

It is difficult to permanently change the composition of the complex intestinal microflora of the adult. Orally administered probiotic bacteria produce only temporary colonization of the intestine in patients with a fully developed gut microflora. The gastrointestinal tract of a healthy fetus is sterile. During the birth process and rapidly thereafter, microbes from the mother and the surrounding environment colonize the gastrointestinal tract until a dense, complex microflora develops. Probiotic bacteria have been shown to beneficially influence the intestinal and systemic immune system and mediate protection against nosocomial infections affecting the neonate. The purpose of this study was to determine whether oral administration of the probiotic micro-organism Lactobacillus rhamnosus strain GG (L. GG) to the pregnant woman leads to colonization of the newborn infant.