Emerging Invasive Group A Streptococcus M1 Lineage Detected by Allele-Specific PCR, England, 2020.

Increasing reports of invasive Streptococcus pyogenes infections mandate surveillance for toxigenic lineage M1. An allele-specific PCR was developed to distinguish M1 from other emm1 strains. The M1 lineage represented 91% of invasive emm1 isolates in England in 2020. Allele-specific PCR will permit surveillance for M1 without need for genome sequencing.