Whole-genome sequencing of invasive and non-invasive Group A Streptococcus (GAS)

Clinical cases of invasive Group A Streptococcus (GAS) and/or laboratory isolation of GAS from sterile sites were made nationally notifiable through local Public Health Units in Australia in 2022. This decision, in part was made to better understand the dynamics of invasive GAS including the global increase and emergence of new infection subtypes occurring globally (especially the recent M1UK clone which emerged from the global pandemic emm1 clone). Whole genome sequencing of GAS is considered as an important component of this directive with data not only aiding interventions but also informing vaccine development. However, the burden of GAS infection remains non-invasive and as such sampling only invasive isolates may introduce a bias which would dilute any subsequent intervention and reduce its impact. To address this question, we undertook sequencing of both invasive and non-invasive GAS isolates from two distinct hospital isolate collections.