Influência do leite materno sobre a população de Lactobacillus spp. nas fezes de recém-nascidos

Abstract

During breastfeeding several species of bacteria present in milk can be transmitted to the newborn. Among these bacteria, many species of Lactobacillus play a relevant role as probiotics and are considered important for the child's health. The objective of this study was to investigate the influence of breastfeeding on the fecal population of Lactobacillus of newborns in the three lactation periods (colostrum, transitional milk and mature milk), analyzing the probiotic potential of Lactobacillus. Eighteen mothers and their respective newborns were selected for the study. All were born by normal birth and all had full term gestation. Bacterial colonies with phenotypic characteristics similar to Lactobacillus had their genetic material extracted and submitted to Polymerase Chain Reaction (PCR) with primers for the 16S rRNA region specific for the genus. In addition, PCR reactions with specific primers to identify species-level isolates were used. In the bacterial isolation process, the faecal samples had the highest Lactobacillus counts in comparison to the breast milk, regardless of the stage of lactation. Bacterial species, including Lactobacillus casei, Lactobacillus paracasei, Lactobacillus animalis, Lactobacillus fermentum and Lactobacillus rhamnosus, from faeces of the newborns and samples of breast milk showed tolerance profiles when submitted to acid pH, lysozyme and salts biliary. These species were able to bind to mucin and also presented antagonistic activity against Enteropathogenic Escherichia coli (EPEC). The results showed that the bacterial species exhibited probiotic potential. In addition, maintenance of Lactobacillus spp. Was observed in the intestinal microbiota during all stages of lactation. The greater amount of Lactobacillus in fecal samples suggests that the intestinal tract represents an ecosystem suitable for colonization by Lactobacillus. The results of the study showed that exclusive breastfeeding is an important factor for the transfer of bacteria of the genus Lactobacillus to the newborns.