Molecular Epidemiology and Virulence Gene Analysis of Methicillin-Resistant Staphylococcus aureus Associated with Skin and Soft Tissue Infections in the Shaoxing Region.

This study aimed to investigate the prevalence, molecular types, and virulence genes of methicillin-resistant Staphylococcus aureus (MRSA) causing skin and soft tissue infections (SSTIs) in the Shaoxing region. MRSA strains were collected from patients with SSTIs in Shaoxing People's Hospital from January 2019 to December 2019. We conducted SCCmec typing, Staphylococcus protein A (SPA) typing, multilocus sequence typing (MLST), and virulence gene analysis using whole-genome sequencing on all MRSA strains. The detection rate of community-acquired MRSA (CA-MRSA) isolated from SSTI patients in our hospital was 33.3% (6/18). The primary SCCmec types of CA-MRSA strains were IV and V, with IVg(2B) and V(5C2&5) accounting for 16.7% each. Hospital-acquired MRSA (HA-MRSA) strains primarily exhibited SCCmec types IVa(2B) (25.0%), followed by II(2A) (16.7%), V(5C2) (16.7%), and V(5C2&5) (8.3%). SPA typing indicated that CA-MRSA strains causing SSTIs were predominantly t437 (14.3%), t034 (14.3%), t309 (14.3%), t4549 (14.3%), and t7637 (14.3%). The primary SPA type of HA-MRSA strains was t311 (16.7%). MLST typing revealed that the main sequence types (STs) of CA-MRSA strains causing SSTIs were ST22 (33.3%), followed by ST398, ST59, ST88, and ST630, each accounting for 16.7%. The principal STs of HA-MRSA strains were ST398 (16.7%), ST59 (16.7%), ST88 (16.7%), and ST5 (16.7%), followed by ST22, ST630, ST6, and ST188, each at 8.3%. The primary clones of CA-MRSA strains causing SSTIs were ST59-t437-IVg(2B) (16.7%) and ST630-t4549-V(5C2&5) (16.7%), while the primary clones of HA-MRSA strains were ST59-t437-IVa(2B), ST630-t4549-V(5C2&5), ST6-t304-IVa(2B), ST5-t311-II(2A), ST59-t172-IVa(2B), ST398-t571-V(5C2), ST398-t034-V(5C2), and ST5-t311-II(2A), each accounting for 8.3%. The detection rate of the lukSF-PV virulence gene was higher in CA-MRSA strains (50.0%) than in HA-MRSA strains (16.7%). The isolation rate of CA-MRSA strains causing SSTIs was high in Shaoxing People's Hospital, with ST59-t437-IVg(2B) and ST630-t4549-V(5C2&5) being the predominant clones. MRSA strains exhibited multiple virulence genes, with the lukSF-PV gene having a higher detection rate in CA-MRSA strains, signifying its importance as a virulence factor in CA-MRSA.