Large-scale genomic analysis places Chinese CC398 as a persistent human-associated MSSA lineage apart from the dominant global LA-MRSA clade.

Chinese CC398 predominantly comprises human-associated MSSA lineages with unique East Asia-specific phylogroups, contrasting with the livestock-associated MRSA lineages in Western countries.

• Why it matters: Understanding regional diversification of CC398 is crucial for developing targeted surveillance and control strategies, as its evolutionary paths differ across regions.
• What they did: The study applied a core-genome multilocus sequence typing scheme to over 30,000 S. aureus genomes, revealing distinct phylogroups, resistance profiles, and a limited LA-MRSA presence in China, with transmission linked to international trade only after 2019.
• The result: Findings suggest that CC398's evolution in China diverges from Western patterns, emphasizing the importance of region-specific surveillance and highlighting additional lineage-enriched genes like cadC that may influence host adaptation.