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Published on: August 15, 2025
Six-month multicenter study on invasive infections due to Streptococcus pyogenes and Streptococcus dysgalactiae
Horacio A Lopardo1, Patricia Vidal, Monica Sparo
1Servicio de Microbiología. Hospital de Pediatría Prof. Dr. Juan P. Garrahan, Combate de los Pozos 1881. (1245) Buenos Aires, Argentina. hlopardo@garrahan.gov.ar
Abstract:
During a 6-month period, 95 invasive infections due to Streptococcus pyogenes and group C or group G Streptococcus dysgalactiae subsp. equisimilis were recorded from 40 centers of 16 cities in Argentina. We describe here epidemiologic data available for 55 and 19 patients, respectively, associated with invasive infections due to S. pyogenes and S. dysgalactiae subsp. equisimilis. The associated isolates and 58 additional pharyngeal isolates were genotyped and subjected to serologic and/or antibiotic susceptibility testing. Group A streptococcal emm type distribution and strain association with toxic shock appeared to differ somewhat from results found within the United States; however, serologic characterization and sof sequence typing suggested that emm types found in both countries are reflective of shared clonal types.
Insights
Invasive infections caused by Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis were studied in Argentina. Findings suggest shared clonal types between Argentina and the United States, despite some differences in emm type distribution.
Area of Science:
- Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Invasive infections due to Streptococcus pyogenes (group A Streptococcus) and Streptococcus dysgalactiae subsp. equisimilis (group C/G Streptococcus) pose significant public health concerns.
- Understanding the epidemiology and genetic characteristics of these bacteria is crucial for effective prevention and treatment strategies.
Purpose of the Study:
- To investigate the epidemiologic data and molecular characteristics of invasive Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis infections in Argentina.
- To compare findings with data from the United States to identify potential shared clonal types.
Main Methods:
- Collection of clinical isolates from invasive infections and pharyngeal infections across 40 centers in 16 Argentinian cities over a 6-month period.
- Genotyping of isolates using emm typing and sof sequence typing.
- Serologic characterization and antibiotic susceptibility testing of selected isolates.
Main Results:
- Data were available for 55 patients with invasive S. pyogenes infections and 19 patients with invasive S. dysgalactiae subsp. equisimilis infections.
- emm type distribution and association with toxic shock in S. pyogenes strains showed some differences compared to US data.
- Serologic and sequence typing indicated that emm types found in both countries likely represent shared clonal types.
Conclusions:
- The study identified key epidemiologic features of invasive streptococcal infections in Argentina.
- Despite regional variations, shared clonal types of Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis likely exist between Argentina and the United States.
- Further research is warranted to elucidate the global epidemiology and evolution of these important pathogens.
