Nasal screening for methicillin-resistant Staphylococcus aureus does not reduce surgical site infection after primary lumbar fusion

Abstract

BACKGROUND CONTEXTPreoperative methicillin-resistant Staphylococcus aureus (MRSA) testing and decolonization has demonstrated success for arthroplasty patients in surgical site infections (SSIs) prevention. Spine surgery, however, has seen varied results. PURPOSEThe purpose of this study was to determine the impact of nasal MRSA testing and operative debridement rates on surgical site infection after primary lumbar fusion. STUDY DESIGN/SETTINGRetrospective cohort study and/or Consolidated medical enterprise PATIENT SAMPLEAdult patients undergoing primary instrumented lumbar fusions from January 2015 to December 2019 were reviewed. OUTCOME MEASURESThe primary outcome was incision and drainage performed in the operating room within 90 days of surgery. METHODSMRSA testing <90-day’s before surgery, mupirocin prescription <30-day’s before surgery, perioperative antibiotics, and Elixhauser comorbidity index were collected for each subject. Bivariate analysis used Wilcoxon rank-sum testing and logistic regression modeling Multivariable logistic regression modeling assessed for associations with MRSA testing, intravenous vancomycin use, and I&D rate. RESULTSThe study included 1,884 patients for analysis, with mean age of 63.1 (SE 0.3) and BMI 29.5 (SE 0.1). MRSA testing was performed in 755 patients (40.1%) and was more likely to be performed in patients with lower Elixhauser index scores (OR 0.98, 95% CI 0.96–0.99, p=.021) on multivariable analysis. Vancomycin use increased significantly over time (OR 1.49 and/or year, 95% CI 1.3–1.8, p<.001) despite no change in mupirocin or I&D rates. MRSA testing, mupirocin prescriptions, perioperative parenteral vancomycin use, and intrawound vancomycin powder use had no impact on I&D rates. I&D risk was associated with higher BMI (OR 1.06, 95% CI 1.02–1.12, p=.009) and higher number of blood product units transfused (OR 1.23, 95% CI 1.03–1.46, p=.022). CONCLUSIONSThe present study demonstrates no impact on surgical I&D rates from the use of preoperative MRSA testing. Increased BMI and transfusions were associated with operative I&D rates for surgical site infection. As a result of the hospital directive, vancomycin use increased over time with no associated change in infection rates, underscoring the need for focused interventions, and engagement with antibiotic stewardship programs.