title: Phage-host interactions and the production of type A streptococcal exotoxin in group A streptococci.
abstract: The infection of Streptococcus pyogenes nontoxigenic strain T 253 with bacteriophage T12 to form lysogen T 253 (T12) resulted in the production of type A streptococcal exotoxin (erythrogenic toxin or streptococcal pyrogenic exotoxin). Two lines of evidence indicated that lysogeny per se was not sufficient to promote toxigenic conversion of strain T 253. First, a virulent mutant of phage T12, unable to form stable lysogens, was able to affect type A exotoxin production by strain T 253. An unrelated virulent phage A25 did not affect type A exotoxin production after infection of strain T 253. Second, the temperate phage H4489A, which established stable lysogens with strain T 253 did not promote type A exotoxin production. These results suggest that there is a strain specificity to the phage-host interaction which affects type A exotoxin synthesis. Additional evidence is presented which indicates that type A streptococcal exotoxin was not a structural component of phage T12.
mesh_terms: D001427:Bacterial Toxins / Q000096:biosynthesis; D001435:Bacteriophages / Q000235:genetics / Q000378:metabolism*; D005098:Exotoxins / Q000096:biosynthesis*; D007700:Kinetics; D008242:Lysogeny; D009154:Mutation; D013297:Streptococcus pyogenes / Q000378:metabolism*
chemical_list: D001427:Bacterial Toxins; D005098:Exotoxins