Genomic epidemiology of invasive Group A Streptococcus infections in Argentina, 2023: high prevalence of <i>emm</i> 1-global and detection of <i>emm</i> 1 hypervirulent lineages

The aim of this study is to describe the genomic epidemiology of invasive Group A Streptococcus (iGAS) in Argentina during 2023. A total of 476 invasive GAS isolates were subtyped and analyzed by whole-genome sequencing. A high prevalence of the <i>emm</i>1-type strain was observed. Among the <i>emm</i>1 strains, two highly virulent international variants, <i>emm</i>1-UK and <i>emm</i>1-DK, were identified. Additionally, a local variant, called <i>emm</i>1-ST1319, was detected. This seminal study provides initial insights into the genomic landscape of iGAS, contributing to active surveillance to monitor emerging virulent <i>emm</i>1 lineages and cross-border transmission in South America.IMPORTANCEAmid the increase in invasive <i>Streptococcus pyogenes</i> infections in Argentina in 2023, the implementation of genomic analysis of isolates allowed us to detect at the national level the prevalence of the <i>emm</i>1 type and within the M1 type, emerging national and international hypervirulent lineages. These findings from our report shed light on the distribution of invasive Group A Streptococcus, laying the foundation for genomic surveillance of this pathogen.