Increasing reports of invasive Streptococcus pyogenes infections mandate surveillance for toxigenic lineage M1UK. An allele-specific PCR was developed to distinguish M1UK from other emm1 strains. The M1UK lineage represented 91% of invasive emm1 isolates in England in 2020. Allele-specific PCR will permit surveillance for M1UK without need for genome sequencing.
Keywords: England; M1UK; PCR; Streptococcus pyogenes; allele-specific; bacteria; emerging lineage; emm1; group A Streptococcus; iGAS; molecular diagnostics; respiratory infections; scarlet fever; streptococci; superantigen.