Convergent adaptation in the dominant global hospital clone ST239 of methicillin-resistant Staphylococcus aureus

Abstract

Infections caused by highly successful clones of hospital-associated methicillin-resistant Staphylococcus aureus (HAMRSA) are a major public health burden. The globally dominant sequence type 239 (ST239) HA-MRSA clone has persisted in the health care setting for decades, but the basis of its success has not been identified. Taking a collection of 123 ST239 isolates spanning 32 years, we have used population-based functional genomics to investigate the evolution of this highly persistent and successful clone. Phylogenetic reconstruction and population modeling uncovered a previously unrecognized distinct clade of ST239 that was introduced into Australia from Asia and has perpetuated the epide..