Outpatient Antibiotic Stewardship: A Growing Frontier—Combining Myxovirus Resistance Protein A With Other Biomarkers to Improve Antibiotic Use

Joseph, Patrick; Godofsky, Eliot

Rapid CRP tests are shown to promote more prudent use of antibiotics in primary care and have led to a 19% reduction in antibiotic prescriptions [66] . A prospective, multicenter, cross-sectional study of adults and children with febrile URIs evaluated the diagnostic accuracy of a 15-minute, single-use disposable immunoassay that includes both CRP and MxA (FebriDx; RPS Diagnostics, Sarasota, FL) [8] . During a multicenter, US-based study that enrolled 370 patients, 205 symptomatic patients with URI and 165 asymptomatic patients from 10 clinical sites, including academic emergency departments and community care centers, demonstrated a 97% negative predictive value (NPV) for bacterial infection. Also, the use of CRP independent of MxA would have led to overtreatment of 38% of viral infections [8] . The pattern of results from test systems with CRP or PCT combined with MxA may assist health care professionals to identify an immune response to a suspected viral and/or bacterial infection and greatly enhance antibiotic stewardship in the outpatient setting [7, 24] . This was recently demonstrated in a FebriDx study of 21 children and adults (mean age = 46 years) that evaluated the use of MxA plus CRP as a guide for outpatient antibiotic management. Therapy was altered in 48%, and unnecessary antibiotic prescriptions were reduced by 80% without any adverse effects [9] .