Can preoperative screening for methicillin-resistant staphylococcus aureus effectively predict surgical site infections in spine surgeries?

Abstract

Introduction: Hospital care-associated infections prolong hospital stay and thus increased financial burden, causes long-term disability and mortality in patients and can increase resistance of microorganisms to antimicrobials. Surgical site infections (SSIs) are the most frequent type of hospital care-associated infections in the developing countries. Staphylococcus is the most commonly isolated organism with methicillin-resistant Staphylococcus aureus (MRSA) posing a great threat. The most common human reservoir for S. aureus is the nares. We propose a study to evaluate the efficacy of preoperative screening of MRSA by nasal and throat culture by correlating it with postoperative SSI. Study Design: Prospective study. Purpose of the Study: 1. To determine the prevalence of MRSA colonization in a population of patients scheduled for elective spine surgery. 2. To determine whether preoperative nasal and throat swab cultures for MRSA are predictive of postoperative SSI in patients undergoing spine surgery. Materials and Methods: Two hundred and forty-eight patients who underwent spine surgery at Baby Memorial Hospital, Calicut, from December 2018 onward are included in this study. Patients who had spine surgeries for infections were excluded from the study. Patients who developed postoperative SSIs were cross-checked with preoperative data and analyzed whether the infecting organism is same as in the preoperative nasal and throat swab culture (if it is present). The significance of the correlation between preoperative nasal and throat swab culture and postoperative SSI are assessed statistically with Chi-square test. Discussion: Among the 248 patients in this study, preoperative nasal and throat swab culture yielded MRSA in 27 patients (nasal – 24, throat – 2, and both – 1). Out of 248 patients, 6 patients developed SSIs with MRSA, but none of them had MRSA in preoperative nasal or throat swab culture. Conclusion: Preoperative MRSA screening by throat and nasal swab is not routinely needed in spine surgery as it appears to carry no positive predictive value in postoperative SSIs.