Many countries have reported increasing rates of penicillin-susceptible methicillin-sensitive Staphylococcus aureus (MSSA-PENS). To date, there is relatively little known about the current situation and molecular characteristics of MSSA-PENS in China. In this study, we carried out a laboratory-based multi-region retrospective study to investigate the genomic epidemiology and characterisation of MSSA-PENS isolated from invasive bloodstream infections (BSIs) across 17 provinces. The prevalence of MSSA-PENS isolates increased significantly over the 6-year period, with the proportion increasing from 3.51% in 2014–8.80% in 2019, an average relative increase of 22.14% per year (95% confidence interval 9.67%-34.61%, P for trend