Abstract

Probiotics are defined as “living microorganisms which when administered in adequate amounts confer a healthbenefit on the host”. Classically, searching for bacterial strains able to exert beneficial effects on human health has beenfocused on the natural inhabitants of our gastrointestinal tract, mainly being directed at members of the genera Bifidobacterium and Lactobacillus. In the last few years, a substantial body of scientific evidence suggests that other bacterial genera could rationally be screened for use as probiotics. We have focused the present article on this issue and,more precisely, on the commensal microbiota of human milk. Apart from lactobacilli and bifidobacteria, with a clear interest as probiotics, the commensal microbiota of human milk includes enterococci, streptococci and staphylococci. These microorganisms might play important roles in the proper development of the infant gut. However, their potential benefits remain nowadays unexplored, as long as they are included in genera with pathogen representatives. The issue ofsearching potential probiotic strains within those genera is discussed in this article.