Methicillin-Resistant Staph Aureus (MRSA) Nasal Swab Utilization as a Predictor for MRSA Skin & Soft Tissue Infections: A Systematic Review and Meta-analysis

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) infections are associated with high morbidity and mortality. Conversely, antibiotics to treat them also have risks. Interest regarding the use of MRSA nasal swabs to predict active MRSA infection has recently increased. Evidence for this practice varies by infection type, and is still emerging for skin and soft tissue infections (SSTI). We performed a systematic review and meta-analysis to examine the clinical utility of MRSA nasal swabs for the prediction of this organism as a cause of SSTI. Methods Electronic databases were systematically searched to identify studies investigating MRSA nasal swabs and SSTI between January 1, 2000 and January 1, 2025. Potentially relevant articles were selected based on inclusion and exclusion criteria. Studies were combined and data extracted. Data was analyzed to calculate pooled overall and subgroup sensitivity, specificity, odds ratio, positive predictive value, and negative predictive value. Results Twenty-five studies were included. The overall positive predictive value was 70%, negative predictive value 87%, and diagnostic odds ratio 18.8. The sensitivity, specificity, positive predictive value, and negative predictive value were 57%, 94%, 77%, and 87% for a mixed composite of SSTIs; 59%, 95%, 71%, and 91% for purulent infections, 45%, 94%, 63%, and 87% for diabetic foot infections, and 20%, 94%, 48%, and 79% for surgical site infections, respectively. Conclusion MRSA nasal screening as a predictor for MRSA SSTIs has a high negative predictive value only in areas where MRSA prevalence is low. Notably, we found a low sensitivity and positive predictive value overall and across subgroups. The results were limited by high overall heterogeneity in the pooled values.