Association of Methicillin-Resistant Coagulase-Negative Staphylococci on Preoperative Skin and Surgical Site Infection in Patients Undergoing Spinal Surgery: A Retrospective Cohort Study

INTRODUCTION: The aim of this study was to investigate the association of methicillin-resistant coagulase-negative staphylococci (MRCNS) on preoperative skin and surgical site infections (SSIs) in patients undergoing spinal surgery. METHODS: A total of 507 cases (239 males and 268 females; mean age: 56.1 years) were included in this retrospective study, using prospectively collected data. All patients underwent skin culturing of the surgical site preoperatively. To identify independent risk factors for SSIs as the dependent variable, sequential multivariate logistic regression analyses were conducted. Age, sex, body mass index, presence of rheumatoid arthritis (RA), steroid uses, the American Society of Anesthesiologists Physical Status (ASA-PS) ≥3, MRCNS-positivity on skin bacterial culture, instrumentation, and Japanese Orthopedic Association (JOA) score were used as independent variables. RESULTS: Preoperatively, MRCNS was detected from skin culture in 50 (9.9%) cases. The frequency of RA, steroid uses, and ASA-PS ≥3 was significantly higher in MRCNS-positive cases than in MRCNS-negative cases. There were 21 (4.1%) post-spinal surgery SSI cases. Multivariate logistic regression analyses revealed that JOA scores (odds ratio (OR), 0.864; 95% confidence interval (CI), 0.764-0.977) and MRCNS-positivity (OR, 5.060; 95% CI, 1.787-14.323) were significantly associated with SSIs. CONCLUSIONS: Preoperatively, the incidence of MRCNS was 9.9%; it was the most common cause of postoperative SSIs. MRCNS-positivity was the most associated factor for SSIs.