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Molecular Genetic Characterization of Streptococcus pyogenes Strains Isolated from Patients with Various
A G Minko1, T A Danilova2, G A Danilina2
1Laboratory of Indication and Ultrastructural Analysis of Microorganisms, N. F. Gamaleya National Research Center of Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia. alexi-m@yandex.ru.
Abstract:
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.
Insights
This study analyzed 82 Streptococcus pyogenes strains, finding diverse emm-types and widespread superantigen genes. Most strains carried multiple superantigen genes, showing significant genetic variation linked to emm-type.
Area of Science:
- Microbiology
- Molecular Biology
- Infectious Diseases
Background:
- Streptococcus pyogenes (group A streptococci) causes various infections.
- Understanding the genetic diversity of S. pyogenes, particularly its superantigen genes, is crucial for disease pathogenesis and epidemiology.
Purpose of the Study:
- To characterize the emm-types and superantigen gene profiles of clinical S. pyogenes isolates.
- To investigate the association between emm-types and the distribution of superantigen genes.
Main Methods:
- emm-typing was performed on 82 clinical S. pyogenes strains.
- Multiprimer PCR and real-time PCR were used to identify superantigen genes (speC, speG, speH, speI, speJ, speK, speL, speM, smeZ, SSA, SpeA, SpeB).
Main Results:
- Twenty-seven emm-types were identified, with emm-89, emm-75, and emm-1 being predominant.
- All strains harbored superantigen genes, with 98% possessing 2-7 different genes.
- High prevalence of speG (93%) and smeZ (98%) was observed, alongside significant variation in other superantigen gene distributions, showing some correlation with emm-type.
Conclusions:
- Clinical isolates of S. pyogenes exhibit considerable diversity in emm-types and superantigen gene content.
- The observed genetic variability, particularly in superantigen gene sets, is partially associated with specific emm-types, influencing S. pyogenes pathogenicity.
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