Whole Genome Sequencing Analysis of Group A Streptococcus Isolates From Pediatric Patients in Korea From 2013 to 2024

Background: Group A Streptococcus (GAS) infections are a significant global health concern.A novel lineage of emm 1 strain (M1 UK ), responsible for invasive GAS (iGAS) infections, which are potentially life-threatening, has been reported globally since 2019.Recent epidemiological studies on GAS using whole genome sequencing (WGS) revealed its usefulness for surveillance of transmission of GAS.Methods: WGS analysis was performed using DNA extracted from cultured GAS isolates stored from 2013 to 2024 at a single center.Clinical data from patients with GAS infection were also analyzed.Results: Fifteen GAS isolates were collected from 12 pediatric patients (median age 4 years, 41.6% male).In patients with iGAS infection, emm 1 (n = 3), emm 12 (n = 4), and emm 89 (n = 1) were identified.In patients with non-iGAS infection, emm 1 (n = 1), emm 4 (n = 1), emm 12 (n = 1), and emm 28 (n = 1) were identified.Phylogenetic analysis and single-nucleotide polymorphism pattern comparison revealed that all emm 1 strains corresponded to M1 global rather than M1 UK .Three patients (two iGAS and one non-iGAS) had isolates from two different sites, for which the emm type was the same.Conclusion: Continuous surveillance of GAS strains is necessary to monitor and respond to the introduction of toxic variants such as M1 UK .