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. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01523899.