Evaluating the Utility of Staphylococcus aureus Nasal Screening in Preventing Surgical Site Infections in Elective Orthopaedic Surgery

BACKGROUND: Use of preoperative Staphylococcus aureus nasal screening and decolonization varies across orthopaedic surgery. The efficacy of universal nasal screening with regard to surgical site infection (SSI) rates remains unclear, particularly in elective orthopaedic procedures. METHODS: We conducted a multicenter retrospective cohort study of adults who underwent elective orthopaedic surgery. Patients were stratified by S. aureus nasal screening status within 90 days prior to surgery. Deep SSI (within 90 days postoperatively) was the primary outcome, and superficial SSI (within 7 to 30 days postoperatively) was defined as the secondary outcome. We used doubly robust adjustment involving propensity-score matching on 9 variables followed by logistic regression analysis with demographic and clinical covariates. RESULTS: The cohorts comprised 25,005 patients each (mean age, 63 years; 51% female; 88% White). After adjustment, screening was associated with lower odds of developing deep SSI (odds ratio [OR], 0.52 [95% confidence interval (CI), 0.39 to 0.70]; p < 0.001) and superficial SSI (OR, 0.67 [95% CI, 0.62 to 0.73]; p < 0.001). A positive, versus negative, methicillin-resistant S. aureus (MRSA) result was associated with an increased risk of deep (1.47% versus 0.41%; OR, 3.65 [95% CI, 1.59 to 8.38]; p < 0.001) and superficial (12.96% versus 7.63%; OR, 1.80 [95% CI, 1.34 to 2.42]; p < 0.001) SSI. Among screened patients with a deep SSI, only 5.7% had tested positive for MRSA on the screening test. CONCLUSIONS: Preoperative S. aureus nasal screening was associated with a significant reduction in the odds of developing deep and superficial SSIs following elective orthopaedic surgery. However, the overall incidence of deep infection was low, and the MRSA infection rate was negligible. These findings suggest that universal S. aureus nasal screening may have limited value and support consideration of targeted screening in higher-risk surgical populations. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.