Population of invasive group A streptococci isolates from a German tertiary care center is dominated by the hypertoxigenic virulent M1UK genotype

Purpose Hypertoxigenic Streptococcus pyogenes emm1 lineage M1(UK) has recently been associated with upsurges of invasive infections and scarlet fever in several countries, but whole-genome sequencing surveillance data of lineages circulating in Germany is lacking. In this study, we investigated recent iGAS isolates from our laboratory at a German tertiary care center for the presence of the M1(UK) lineage.Methods Whole-genome sequencing was employed to characterize a collection of 47 consecutive non-copy isolates recovered from blood cultures (21) and tissue samples (26) in our laboratory between October 2022 and April 2023.Results M protein gene (emm) typing distinguished 14 different emm types, with emm1 (17) being the dominant type. Single-nucleotide polymorphism (SNP) analysis confirmed the presence of all 27 SNPs characteristic for the M1(UK) lineage in 14 of 17 emm1 isolates.Conclusion This study has shown for the first time that M1(UK) is present in Germany and might constitute a driving force in the observed surge of GAS infections. This observation mirrors developments in the UK and other countries and underscores the importance of WGS surveillance to understand the epidemiology of GAS.

Automated summary

This study has shown for the first time that the M1(UK) lineage is present in Germany and may be a driving force behind the observed surge of GAS infections. This observation mirrors developments in the UK and other countries and underscores the importance of whole-genome sequencing surveillance in understanding the epidemiology of GAS.