S. aureus Screening and SSI Risk in Elective Orthopaedic Surgery

Leijs et al. conducted a retrospective cohort study of adults undergoing elective orthopaedic surgery at 22 medical centers from June 2015 through March 2024. The study compared 25,005 patients screened for nasal Staphylococcus aureus within 90 days before surgery with 25,005 patients who were not screened. Screening protocols varied across centers. MRSA-positive patients identified more than five days before surgery received intranasal mupirocin and vancomycin plus cefazolin; other patients received cefazolin prophylaxis.

After risk adjustment, screening was associated with 48% lower odds of deep SSI and 33% lower odds of superficial SSI. However, the overall incidence of deep infection was low, MRSA SSI rates were similar between screened and unscreened groups, and most MRSA SSI cases occurred in patients with negative preoperative screens. A subgroup analysis suggested lower odds of deep SSI with screening in instrumented procedures.

The findings do not establish that universal screening prevents infection across orthopaedic procedures. The retrospective design leaves potential for residual confounding; screened patients differed in operative time, length of stay, and implant use, and screening began during the study period. Most screened patients underwent arthroplasty, limiting generalizability. The authors note that screening’s role in arthroplasty is better supported than its role in other procedures, while cost-effectiveness of universal screening remains uncertain.