Breast milk microbiota (concept, sources, role of bacteria for a child and mother)

Abstract

Scientific discoveries of recent years demonstrate a crucial role of the human microbiome in human health. The establishment of a healthy, functional gut microbiota of the newborn requires physiological conditions, one of which is breastfeeding. The role of breast milk as a “direct supplier” of live microbes for the establishment of the newborn gut microbiota became known only at the beginning of the new millennium, previously it was believed that the breast milk was sterile. Today, the breast milk microbiota can be defined as multi-species assemblage, in which microbes interact with each, representing a complex organized ecosystem, among which the genera Streptococcus and Staphylococcus are dominant. Lactobacillus, Pseudomonas, Bifidobacterium, Corynebacterium, Enterococcus, Acinetobacter, Rothia, Cutibacterium, Veillonella and Bacteroides are also often referred to the common bacterial genera. The article presents two theories of the origin of bacteria in the breast milk (endogenous and exogenous bacterial translocation pathways) and explains why both of them are true. The role of bacteria in the breast milk of healthy women, in the global sense, is viewed in the context of the establishment of the infant gut microbiota. The article lists the main producers of antibacterial peptides (bacteriocins) in the breast milk and considers the effective immunological protection using the example of the population of bifidobacteria and bacteroids prevailing in the breastfed infant gut. However, the breast milk microbiota is also important for women’s health. We tried to explain why infectious lactational mastitis is now considered to be the result of dysbiosis in the mammary ecosystem, which leads to the development of an inflammatory process, and why Streptococcus thermophilus (TCI633) shows promise in the fight against human ageing.