title: Bacteriocin-like inhibitory activity associated with beta-hemolytic strains of Streptococcus salivarius.
abstract: Seven beta-hemolytic Streptococcus salivarius isolates produced bacteriocin-like inhibitory activity in deferred antagonism tests using a set of nine indicator bacteria (I1-I9). Five of these S. salivarius strains (KWF, TOVE-R, K17, K21, and K26) were inhibitory to indicators I2, I5, I6, and I7. Mutated non-hemolytic derivatives showed concomitant loss of inhibitory activity against I2, I5, and I6, but retained activity against I7. Inhibitory activity against I2, I5, and I6 was restored in beta-hemolytic revertants of such mutants. Strain 3638 was inhibitory to all of the indicator organisms except I3, and this pattern of inhibitory activity was retained by non-hemolytic derivatives. It appeared that strain 3638 produced an additional broadly-active inhibitory agent, since a mutant (strain 3638A), which was apparently defective in the production of this inhibitor, retained both the beta-hemolytic and I2-, I5-, I6-, and I7-inhibitory activities. Non-hemolytic derivatives of strain 3638A were inhibitory only to I7. Strain 3638, therefore, appeared to produce at least three inhibitory agents: one active only on I7; another acting on I2, I5, and I6 (and associated with beta-hemolytic activity); and a third apparently active on all of the indicators other than I3. S. salivarius strain JH inhibited all nine indicator strains and possessed a beta-hemolytic character which differed from that of the other strains in being readily eliminated on treatment with the plasmid-curing agent novobiocin. Non-hemolytic derivatives of JH retained inhibitory activity against the complete set of indicators.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D001430:Bacteriocins / Q000032:analysis / Q000378:metabolism*; D003470:Culture Media; D003956:Dialysis; D006461:Hemolysis; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D009675:Novobiocin / Q000494:pharmacology; D013291:Streptococcus / Q000145:classification / Q000187:drug effects / Q000378:metabolism*
chemical_list: D001430:Bacteriocins; D003470:Culture Media; D008769:Methylnitronitrosoguanidine; D009675:Novobiocin