Scarlet fever notifications surged across the United Kingdom in spring 2014. Molecular epidemiologic investigation of Streptococcus pyogenes infections in North-West London highlighted increased emm4 and emm3 infections coincident with the upsurge. Unlike outbreaks in other countries, antimicrobial resistance was uncommon, highlighting an urgent need to better understand the drivers of scarlet fever activity.
Keywords: England; London; Streptococcus pyogenes; antimicrobial resistance; bacteria; genotype; notifications; respiratory infections; scarlet fever; streptococci; superantigens.