Oral streptococcal BLIS: Heterogeneity of the effector molecules and potential role in the prevention of streptococcal infections

Streptococci commonly produce bacteriocin-like inhibitory substances (BLIS). Inhibitory molecules characterized to date have included members of bacteriocin classes I, II and III. Streptococcus salivarius, Streptococcus mutans and Streptococcus uberis strains frequently produce multiple bacteriocins of these various classes. Lantibiotics belonging to the streptococcin A-FF22 (SA-FF22) and salivaricin A (SalA) clusters are produced by several oral streptococcal species. Multi-bacteriocin-producing streptococci such as S. salivarius strain K12, which contain a variety of bacteriocin loci located on mega-plasmids, are now finding application as oral probiotics.