Molecular characterization of intestinal microbiota in infants fed with soymilk.

Background: : Intestinal bacteria play an important role in the postnatal development of the immune system. The composition of gut microbiota is profoundly influenced by the infant's diet, but there is little information about the effects of soymilk on the composition of intestinal biota. The present study was designed to investigate the intestinal ecosystem of the newborn in relation to the consumption of soymilk.

Mode of delivery affects the bacterial community in the newborn gut.

The first colonisation of the intestine is one of the most profound immunological exposures faced by the newborn and it is influenced by external and internal factors. The early composition of human microbiota could have long-lasting metabolic effects and the initial composition of human intestinal bacteria is also known to affect postnatal immune system development, as we are already aware that reduced microbial stimulation during infancy would result in slower postnatal maturation of the immune system and development of an optimal balance between TH1 and TH2-like immunity. Mode of delivery has a major role on the composition of intestinal microbiota in early infancy, as it has been shown that infants born by Caesarean section (CS) have lower numbers of Bifidobacteria and Bacteroides compared with vaginally born infants.

Cesarean delivery may affect the early biodiversity of intestinal bacteria.

The gastrointestinal tract of neonates becomes colonized immediately after birth with environmental microorganisms, mainly from the mother; strong evidence suggests that the early composition of the microbiota of neonates plays an important role for the postnatal development of the immune system. The present study was designed to evaluate by means of a molecular biology approach the relation between the intestinal ecosystem of the newborn and the mode of delivery. The intestinal bacterial composition on d 3 of life was investigated in 23 infants born by vaginal delivery and in 23 infants delivered by cesarean section.

Survival of yogurt bacteria in the human gut.

Whether Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus can be recovered after passage through the human gut was tested by feeding 20 healthy volunteers commercial yogurt. Yogurt bacteria were found in human feces, suggesting that they can survive transit in the gastrointestinal tract.