Emergency physician ability to predict methicillin-resistant Staphylococcus aureus skin and soft tissue infections

Methicillin-resistant Staphylococcus aureus (MRSA) has a high prevalence in Emergency Departments (EDs). The objective of this study was to determine the ability of emergency physicians to predict MRSA infection in purulent wounds. A prospective observational study was conducted in an urban, tertiary academic center in ED patients presenting with purulent wounds and abscesses that received wound culture. Physicians completed a questionnaire with patient demographic data and their own suspicion for MRSA infection in eligible patients. For emergency physician ability to predict positive culture for MRSA, sensitivities, specificities, and positive and negative likelihood ratios (LRs) were calculated. Risk factors were assessed for statistical significance using a chi-squared test with p < 0.05. There were 176 patients enrolled, and 19 were eliminated for incomplete data. Physician suspicion of MRSA had a sensitivity of 80% (95% confidence interval [CI] 71%-87%) and a specificity of 23.6% (95% CI 14%-37%) for the presence of MRSA on wound culture with a positive LR of 1.0 (95% CI 0.9-1.3) and a negative LR of 0.8 (95% CI 0.5-1.3). Prevalence was 64%. Only intravenous drug use was significantly associated with MRSA. Emergency physician's suspicion of MRSA infection is a poor predictor of MRSA infection.