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Background <p><i>Streptococcus pyogenes</i> (GAS) causes diseases ranging from mild pharyngitis to severe invasive infections. The <i>emm</i>1 type is the most prevalent worldwide, and a highly transmissible variant, M1<sub>UK</sub>, characterized by increased <i>speA</i> expression, has recently emerged and spread globally.</p> Objective <p>To characterize the genomic diversity of invasive GAS isolates collected from severe cases and epidemiologically important outbreaks in Brazil.</p> Methods <p>Whole-genome sequencing was performed on 229 invasive GAS isolates collected in Brazil between January 2023 and November 2024. Genomes were analyzed for <i>emm</i> typing, lineage assignment, and virulence gene profiling. Comparative genomic analyses, including global M1<sub>global</sub> and M1<sub>UK</sub> genomes, were performed to contextualize the Brazilian isolates within the global population structure.</p> Results <p>Thirty-four distinct <i>emm</i> types were identified, with <i>emm</i>1 accounting for 52.4%. Of these, 14% were confirmed as M1<sub>UK</sub> clones, detected across multiple Brazilian regions. Comparative genomic analysis showed that the remaining <i>emm</i>1 isolates clustered into a well-supported group representing a genetically distinct Brazilian sublineage (Br clade).</p> Conclusion <p>The detection of M1<sub>UK</sub> isolates in multiple Brazilian states indicates that this lineage is circulating in the country. Most <i>emm</i>1 isolates analyzed in this study belonged to the Br clade rather than the M1<sub>UK</sub> lineage, suggesting that the distribution of <i>emm</i>1 sublineages in this selected dataset differs from patterns reported in countries where M1<sub>UK</sub> has become predominant. These findings highlight the importance of genomic and public health surveillance to monitor and control the spread of invasive GAS infections.</p>

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Genomic analysis of Streptococcus pyogenes emm1-type isolates reveals M1UK circulation and a genetically distinct Brazilian sublineage

  • 期刊论文

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  • 发表日期：

    2026年7月28日

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  • Gisele Aparecida Bernardi,
  • Luiza Souza Rodrigues,
  • José Ferreira da Cunha Neto,
  • Geiziane Aparecida Gonçalves,
  • Lavinia Nery Villa Stangler Arend,
  • Sabrina da Conceição Barbosa,
  • Marcelo Pillonetto,
  • Tadayoshi Ikebe,
  • Yukihiro Akeda,
  • Norihiko Takemoto,
  • Felipe Francisco Tuon

摘要

Background

Streptococcus pyogenes (GAS) causes diseases ranging from mild pharyngitis to severe invasive infections. The emm1 type is the most prevalent worldwide, and a highly transmissible variant, M1UK, characterized by increased speA expression, has recently emerged and spread globally.

Objective

To characterize the genomic diversity of invasive GAS isolates collected from severe cases and epidemiologically important outbreaks in Brazil.

Methods

Whole-genome sequencing was performed on 229 invasive GAS isolates collected in Brazil between January 2023 and November 2024. Genomes were analyzed for emm typing, lineage assignment, and virulence gene profiling. Comparative genomic analyses, including global M1global and M1UK genomes, were performed to contextualize the Brazilian isolates within the global population structure.

Results

Thirty-four distinct emm types were identified, with emm1 accounting for 52.4%. Of these, 14% were confirmed as M1UK clones, detected across multiple Brazilian regions. Comparative genomic analysis showed that the remaining emm1 isolates clustered into a well-supported group representing a genetically distinct Brazilian sublineage (Br clade).

Conclusion

The detection of M1UK isolates in multiple Brazilian states indicates that this lineage is circulating in the country. Most emm1 isolates analyzed in this study belonged to the Br clade rather than the M1UK lineage, suggesting that the distribution of emm1 sublineages in this selected dataset differs from patterns reported in countries where M1UK has become predominant. These findings highlight the importance of genomic and public health surveillance to monitor and control the spread of invasive GAS infections.