Comparative genomics of Methicillin-resistant Staphylococcus aureus ST239: distinct geographical variants in Beijing and Hong Kong

Background: The ST239 lineage is a globally disseminated, multiply drug-resistant hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA). We performed whole-genome sequencing of representative HA-MRSA isolates of the ST239 lineage from bacteremic patients in hospitals in Hong Kong (HK) and Beijing (BJ) and compared them with three published complete genomes of ST239, namely T0131, TW20 and JKD6008. Orthologous gene group (OGG) analyses of the Hong Kong and Beijing cluster strains were also undertaken. Results: Homology analysis, based on highest-percentage nucleotide identity, indicated that HK isolates were closely related to TW20, whereas BJ isolates were more closely related to T0131 from Tianjin. Phylogenetic analysis, incorporating a total of 30 isolates from different continents, revealed that strains from HK clustered with TW20 into the ‘Asian clade’, whereas BJ isolates and T0131 clustered closely with strains of the ‘Turkish clade’ from Eastern Europe. HK iso...