Molecular genetic characterization of Streptococcus pyogenes isolates from pediatric patients in multidisciplinary hospitals in Moscow
Year: 2026
Type: article
Abstract: Background. Streptococcus pyogenes (group A streptococcus, GAS) is a significant human bacterial pathogen causing a wide range of diseases, from upper respiratory tract infections to severe invasive forms. The increase in incidence in the post-COVID-19 period and the spread of hypervirulent clonal lineages, including M1UK (emm1 genotype), highlight the need for molecular genetic surveillance. Aim. To characterize the clonal structure, virulome and resistome of S. pyogenes strains isolated from hospitalized children and to assess their phenotypic antimicrobial susceptibility. Materials and methods. A total of 67 S. pyogenes strains isolated in 2023–2024 from hospitalized patients aged 0–17 years were studied. Identification was performed by MALDI-TOF mass spectrometry. Antimicrobial susceptibility testing was carried out by serial dilution methods. Whole-genome sequencing, genome assembly were performed. Bioinformatic analysis included emm typing, multilocus sequence typing, detection of virulence and antimicrobial resistance genes, and phylogenetic analysis. Results. Fourteen emm types and 19 sequence types were identified. The predominant clonal lineages were emm6/ST382 (16.4%), emm2/ST55 (14.9%), emm3/ST15 and emm75/ST49 (10.4% each). A strong association between emm and sequence types was observed (p 0.001; Cramer's V = 1.0). One strain of the M1UK lineage was identified among emm1/ST28 isolates. The virulence genes sagA, slo, mf/spd and speB were detected in all strains, while hylP was found in 86.6%. Among superantigen genes, speG (89.6%) and speC (68.7%) were most frequent. All strains were susceptible to β-lactams, clindamycin, linezolid, vancomycin. Resistance to erythromycin and tetracycline was detected in 4.5% and 14.9% of strains, respectively, and was predominantly associated with the mef(A)/msr(D) and tetM genes. Conclusion. S. pyogenes strains isolated from hospitalized children are characterized by genetic heterogeneity, a pronounced clonal structure, and genotype-specific distribution of superantigen genes. The results confirm the importance of whole-genome sequencing for monitoring the clonal structure, virulome and resistome of S. pyogenes within molecular epidemiological surveillance of GAS infections.
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7216130042