MRSA screening in emergency department detects a minority of MRSA carriers

INTRODUCTION Methicillin-resistant Staphylococcus areus (MRSA) is an emerging problem. The Danish Health and Medicines Authority (HMA) has developed a question-based screening tool to identify patients with MRSA. The tool has three parts: questions on general risk situations, special risk situations and individual risk factors. The emergency departments (ED) play a key role in the prevention of in-hospital spreading of MRSA. The aim of the present study was to estimate the prevalence of MRSA among all admitted ED patients to assess how many patients should be swab-tested for MRSA and isolated and to evaluate the ability of the HMA screening tool to detect MRSA. METHODS Patients who were more than ten years old answered all the HMA questions on general and specific risk situations and individual risk factors for MRSA, and a swab was obtained for MRSA culture. RESULTS A total of 1,945 patients were admitted and 73% participated. Indications for swab testing for MRSA were present in 8%. The general risk situation questions identified 3% for isolation due to suspicion of MRSA. A total of 11 patients had a positive MRSA swab culture (0.9%). Among the isolated patients, 3% had MRSA, 97% would have been isolated unnecessarily, while 91% of the MRSA patients would not have been isolated. The general risk situation questions had a sensitivity of 18-27% and the whole questionnaire had a sensitivity of 55% for the detection of MRSA patients. CONCLUSIONS The majority of MRSA carriers who are acutely admitted to the ED will remain undetected. FUNDING Hospital of Southern Jutland. TRIAL REGISTRATION not relevant.