Human pathogen S. pyogenes has to pass layers of resident microflora to gain access to its final target, the epithelial cells of upper respiratory tract. Interactions between different S. pyogenes wt strains, selected oral bacteria and E. coli Nissle shown that E. coli Nissle can inhibit S. pyogenes growth by direct contact. The transient microflora E. faecalis can interfere S. pyogenes hemolytic capacity through its excreted substance. S. pyogenes can establish itself as a member of mixed species biofilms with S. oralis, the resident oropharyngeal microflora. S. salivarius acts as probiotic by suppressing S. pyogenes growth and growing as protective biofilms on top of the eukaryotic target cells.