A Randomized Clinical Trial Comparing Use of Rapid Molecular Testing for Staphylococcus aureus for Patients With Cutaneous Abscesses in the Emergency Department With Standard of Care

OBJECTIVE To determine whether real-time availability of rapid molecular results of Staphylococcus aureus would impact emergency department clinician antimicrobial selection for adults with cutaneous abscesses. DESIGN We performed a prospective, randomized controlled trial comparing a rapid molecular test with standard of care culture-based testing. Follow-up telephone calls were made at between 2 and 7 days, 1 month, and 3 months after discharge. SETTING Two urban, academic emergency departments. PATIENTS Patients at least 18 years old presenting with a chief complaint of abscess, cellulitis, or insect bite and receiving incision and drainage were eligible. Seven hundred seventy-eight people were assessed for eligibility and 252 met eligibility criteria. METHODS Clinician antibiotic selection and clinical outcomes were evaluated. An ad hoc outcome of test performance was performed. RESULTS We enrolled 252 patients and 126 were randomized to receive the rapid test. Methicillin-susceptible S. aureus-positive patients receiving rapid test results were prescribed beta-lactams more often than controls (absolute difference, 14.5% [95% CI, 1.1%-30.1%]) whereas methicillin-resistant S. aureus-positive patients receiving rapid test results were more often prescribed anti-methicillin-resistant S. aureus antibiotics (absolute difference, 21.5% [95% CI, 10.1%-33.0%]). There were no significant differences between the 2 groups in 1-week or 3-month clinical outcomes. CONCLUSION Availability of rapid molecular test results after incision and drainage was associated with more-targeted antibiotic selection.