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

Joseph, Patrick; Godofsky, Eliot

CRP is a nonspecific, acute-phase protein that increases during an inflammatory process such as a severe infection. The normal CRP serum concentration is less than 1-3 mg/L and can rise above 500 mg/L in the presence of severe inflammation or infection [7] . A high CRP level generally indicates bacterial rather than viral infection and can also be used to assess disease severity. A systematic review of acute rhinosinusitis showed that a CRP of less than 10 mg/L provided evidence against bacterial sinusitis and a CRP greater than 20 mg/L showed evidence supporting bacterial sinusitis [34] . Calvino et al. showed that CRP elevated above 20 mg/L in nearly all cases of GABHS, ensuring that a clinically significant infection would less likely be missed, but could not differentiate viral from bacterial infection [35] . Similarly, Putto et al. found that in examining 62 children with positive bacterial cultures, 89% showed a CRP elevated over 20 mg/L, consistent with a clinically significant bacterial infection [36] .