Variation in the Type and Frequency of Postoperative Invasive Staphylococcus aureus Infections According to Type of Surgical Procedure

Abstract

Objective.To determine the epidemiological characteristics of postoperative invasive Staphylococcus aureus infection following 4 types of major surgical procedures.Design.Retrospective cohort study.Setting.Eleven hospitals (9 community hospitals and 2 tertiary care hospitals) in North Carolina and Virginia.Patients.Adults undergoing orthopedic, neurosurgical, cardiothoracic, and plastic surgical procedures.Methods.We used previously validated, prospectively collected surgical surveillance data for surgical site infection and microbiological data for bloodstream infection. The study period was 2003 through 2006. We defined invasive S. aureus infection as either nonsuperficial incisional surgical site infection or bloodstream infection. Nonparametric bootstrapping was used to generate 95% confidence intervals (CIs). P values were generated using the Pearson x2 test, Student t test, or Wilcoxon rank-sum test, as appropriate.Results.In total, 81,267 patients underwent 96,455 procedures during the study period. The overall incidence of invasive S. aureus infection was 0.47 infections per 100 procedures (95% CI, 0.43–0.52); 227 (51%) of 446 infections were due to methicillin-resistant S. aureus. Invasive S. aureus infection was more common after cardiothoracic procedures (incidence, 0.79 infections per 100 procedures [95% CI, 0.62–0.97]) than after orthopedic procedures (0.37 infections per 100 procedures [95% CI, 0.32–0.42]), neurosurgical procedures (0.62 infections per 100 procedures [95% CI, 0.53–0.72]), or plastic surgical procedures (0.32 infections per 100 procedures [95% CI, 0.17¬0.47]) (P < .001). Similarly, S. aureus bloodstream infection was most common after cardiothoracic procedures (incidence, 0.57 infections per 100 procedures [95% CI, 0.43–0.72]; P < .001, compared with other procedure types), comprising almost three-quarters of the invasive S. aureus infections after these procedures. The highest rate of surgical site infection was observed after neurosurgical procedures (incidence, 0.50 infections per 100 procedures [95% CI, 0.42–0.59]; P < .001, compared with other procedure types), comprising 80% of invasive S. aureus infections after these procedures.Conclusion.The frequency and type of postoperative invasive S. aureus infection varied significantly across procedure types. The highest risk procedures, such as cardiothoracic procedures, should be targeted for ongoing preventative interventions.