Molecular Genetic Characterization of Streptococcus pyogenes Strains Isolated from Patients with Various Manifestations of Streptococcal Infection

In 82 clinical strains of Streptococcus pyogenes (group A streptococci) isolated from patients with various manifestations of streptococcal infection, emm -typing revealed 27 emm -types ( n =77) with a predominance of emm -89 ( n =15; 18%), emm -75 ( n =9; 11%), and emm -1 ( n =6; 7%); types emm -3, emm -12, and emm -58 ( n =4; 5% each) were found with almost equal frequency; other types were less common. The superantigen genes speC , speG , speH , speI , speJ , speK , speL , speM , smeZ , and SSA were identified in S. pyogenes strains using multiprimer PCR; the genes of the superantigen SpeA and cysteine proteinase SpeB were detected using real-time PCR. All the studied S. pyogenes strains contained superantigen genes, and 98% of the strains had several (from 2 to 7) genes. The number of variants of these sets reached 37; 2% of the strains contained only one superantigen gene. The distribution frequencies of superantigen genes in the studied strains were: speA — 43%; speC — 38%; speG — 93%; speH — 13%; speI — 6%; speJ — 24%; speK — 13%; speL and speM — 11% each; smeZ — 98%; SSA — 15%. All studied S. pyogenes strains contained the speB gene. Our studies have demonstrated that the sets of superantigen genes of group A streptococci are characterized by pronounced diversity to some extent associated with emm- type.