Nasal colonization of Staphylococcus aureus and the risk of surgical site infection after spine surgery: a meta-analysis

BACKGROUND CONTEXT: Nasal colonization of Staphylococcus aureus may increase the risk of surgical site infection (SSI) after spine surgeries, although the results of previous studies were inconsistent. PURPOSE: To evaluate the influences of nasal colonization of S. aureus, methicillin-susceptible SA, and methicillin-resistant SA (MRSA) on the incidence of SSI after spine surgery. STUDY DESIGN/SETTING: Systematic review and meta-analysis. PATIENT SAMPLE: Seven studies including 10,650 patients who underwent nasal swab examination before spine surgeries were included, and 221 patients had nasal colonization of MRSA at baseline. OUTCOME MEASURES: Association between baseline nasal colonization of S. aureus, MRSA, and SSI after spine surgery. METHODS: Relevant follow-up studies were identified through systematic searches of the PubMed, Embase, and Cochrane Library databases. A random effects model was applied to pool the results. Subgroup analyses were performed according to whether MRSA decolonization was applied. RESULTS: During follow-up, a total of 244 SSI events occurred, including 57 MRSA-SSI events. Pooled results showed that nasal S. aureus (risk ratio [RR]=0.75, p=.22) or methicillin-susceptible SA colonization (RR=0.60, p=.22) did not significantly affect the risk of overall SSI after surgeries. However, nasal MRSA colonization was associated with significantly increased risks of overall SSI and MRSA-SSI (RR=2.52 and 6.21, respectively, both p<. 001). Interestingly, the associations between nasal MRSA colonization and increased risks of overall and MRSA-SSI remained significant in studies without MRSA decolonization, but became insignificant in studies with MRSA decolonization. CONCLUSIONS: Nasal MRSA colonization may be associated with increased risks of overall SSI and MRSA-SSI after spine surgeries, and nasal MRSA decolonization may be associated with a reduction of SSI in these patients. (C) 2019 Elsevier Inc. All rights reserved.