Production of broad-spectrum bacteriocin-like activity by group A streptococci of particular M-types.
Application of a bacteriocin production (P)-typing scheme to group A streptococci has shown that approximately 10% of the tested strains inhibit the growth of all 9 indicator bacteria, an activity referred to as P-type 777. Production of such activity was found to be restricted to 14 M-serotypes and within these M-types the incidence of P-type 777 activity was very high. There was no evidence of any correlation with the T-antigenic composition of the bacteria. Investigations of the conditions for production of P-type 777 activity and of its spectrum of activity indicate that the same inhibitory substance(s) are responsible for this inhibition in the various M-types of streptococci. Group C streptococcus strain T277 produces an inhibitor which has a similar activity spectrum to that of the P-type 777 group A streptococci, but there were considerable differences in the production conditions. Whereas the group C inhibitor was particularly dependent on conditions of incubation (37 degrees C, anaerobic) the group A activity was more dependent on the composition of the test medium (source of blood agar base and blood requirement). All of the tested P-type 777 group A streptococci had identical inhibitory spectra. This was principally directed against gram-positive bacteria, including the producer strains themselves. Of interest was the occurrence of some insensitive strains in otherwise susceptible species of bacteria and the discovery of one sensitive gram-negative strain, Bacteroides intermedius. Production of P-type 777 activity does not appear to correlate with production of various streptococcal enzymes, including protease, hemolysin, DNase and amylase. Many P-type 777 strains are producers of opacity factor, another M-type-associated product of group A streptococci. It is suggested that by the combined testing of group A streptococci for P-type 777 activity and for opacity factor it would be possible to narrow the choice of M-antisera to be used for typing purposes.
Hynes
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Tagg
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D000681:Amylases / Q000096:biosynthesis; D001419:Bacteria / Q000187:drug effects; D001430:Bacteriocins / Q000096:biosynthesis* / Q000494:pharmacology; D003851:Deoxyribonucleases / Q000096:biosynthesis; D006460:Hemolysin Proteins / Q000096:biosynthesis; D010447:Peptide Hydrolases / Q000096:biosynthesis; D013045:Species Specificity; D013297:Streptococcus pyogenes / Q000145:classification / Q000201:enzymology / Q000378:metabolism*
D001430:Bacteriocins; D006460:Hemolysin Proteins; C021908:opacity factor; D003851:Deoxyribonucleases; D000681:Amylases; D010447:Peptide Hydrolases