Detection of Streptococcus pyogenes M1UK in Australia and characterization of the mutation driving enhanced expression of superantigen SpeA

A variant of group A Streptococcus serotype M1 (UK) has been increasingly reported and can be differentiated from the global variant by its overexpression of the superantigen SpeA. Here, Davies et al probe the mechanism behind enhanced SpeA expression and demonstrate that a SNP in the 5’ leader sequence of ssrA is responsible for this virulence phenotype.