Streptococcis as probiotics

Metagenomics and functional molecular immunology substantiate the interpretation of humans as holobionts, in the sense of functional superorganisms, combining the self and microbes acting in concert to produce phenomena governed by the collective. The association between host and symbionts affects the fitness of the holobiont. Bacteria within the resident communities that colonize mucosal sites outnumber cells of the human body by 10-fold. Such communities are diverse and constituted by numerous taxa; for example, more than 700 taxa are normal inhabitants of the human oropharynx. Some of this population are known to provide significant benefit by counteracting pathogen colonization and by modulating the host immune system. This concept of beneficial bacteria has led to the advent of probiotics as a tool to develop a realistic therapeutic and prophylactic strategy for many inflammatory diseases and infections. In this context, several studies showing the probiotic role of nonpathogenic streptococci both in the modulation of the immune responses through the action on the NF-κB signaling pathways of human epithelial pharyngeal cells, and counteracting the adhesion and the growth of oral pathogenic streptococci, will be presented.