title: Prevention of streptococcal pharyngitis by anti-Streptococcus pyogenes bacteriocin-like inhibitory substances (BLIS) produced by Streptococcus salivarius.
abstract: OBJECTIVE
  Streptococcus salivarius is a numerically prominent member of the human oral microbiota that produces a variety of bacteriocin-like inhibitory substances (BLIS) having in vitro inhibitory activity against S. pyogenes. Our previous studies of S. salivarius isolates from children using a deferred antagonism BLIS production (P)-typing scheme showed that the 9 per cent of children having large populations of P-type 677 S. salivarius experienced fewer S. pyogenes acquisitions than either the 11 per cent of children having predominant P-type 226 populations or the 60 per cent of children with largely non-inhibitory (P-type 000) S. salivarius. Amongst the other BLIS P-types detected were a number of strongly-inhibitory (P-type 777) S. salivarius. In the present study the inhibitory agents produced by prototype strains of P-types 226, 677 and 777 S. salivarius are compared.
  
  
  METHODS
  The prototype BLIS-producing S. salivarius strains SN, 20P3, and K12 were isolated from tongue swabbings. BLIS P-typing was done using standard procedures. The BLIS molecules were purified and characterized.
  
  
  RESULTS
  S. salivarius SN (P-type 226) produces a heat-labile muramidase. S. salivarius 20P3 (P-type 677) produces the 2315 Da lantibiotic salivaricin A and S. salivarius K12 (P-type 777) produces two lantibiotics; salivaricin A2 (2368 Da) and salivaricin B (2733 Da).
  
  
  CONCLUSIONS
  The P-type 777 S. salivarius strain produced salivaricin A2 and salivaricin B. The combined production of two anti-S. pyogenes BLIS activities by this strain indicates that it could be adopted as a colonizing strain in bacterial interference trials.
authors.affiliation: Department of Microbiology, University of Otago, P.O. Box 56, Dunedin, New Zealand. john.tagg@stonebow.otago.ac.nz
authors.forename: J R
authors.initials: JR
authors.lastname: Tagg
mesh_terms: D000595:Amino Acid Sequence; D001430:Bacteriocins / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D008969:Molecular Sequence Data; D010612:Pharyngitis / Q000382:microbiology / Q000517:prevention & control*; D013045:Species Specificity; D013290:Streptococcal Infections / Q000382:microbiology / Q000517:prevention & control*; D013291:Streptococcus / Q000378:metabolism*; D013297:Streptococcus pyogenes / Q000187:drug effects*
chemical_list: D001430:Bacteriocins