M1UK in Taiwan
Background: A new sublineage of emm1 group A Streptococcus (GAS), M1UK, has emerged in Europe, North America, and Australia. Notably, a significant portion of emm1 isolates in Asia, particularly in Hong Kong and mainland China, acquired scarlet fever-associated prophages following the 2011 Hong Kong scarlet fever outbreak. However, the presence of the M1UK sublineage has not yet been detected in Asia until 2017.  Methods: This study included GAS isolates (2011-2021). The emm type of these isolates were determined, and emm1 isolates underwent analysis. The presence of the scarlet fever-associated prophages and the specific single nucleotide polymorphisms of the M1UK clone were determined by polymerase chain reaction and the genome sequencing.