Abstract

In this issue of EM Practice Guidelines Update, the Infectious Diseases Society of America (IDSA) new guidelines¹ for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection in adults and children are reviewed. MRSA can cause a wide spectrum of disease, including simple and complicated skin and soft-tissue infections (SSTIs), bacteremia and endocarditis, pneumonia, bone and joint infections, central nervous system (CNS) infections, and sepsis syndrome. Community-associated MRSA (CA-MRSA) has been associated with a major increase in emergency department (ED) visits and hospitalizations for skin and soft-tissue infections in recent years.^2,3 The evidence available to direct the treatment of patients with suspected MRSA is weak, yet emergency clinicians must make decisions regarding antibiotic use and selection almost every day. This guideline provides direction, albeit largely based on expert opinion rather than evidence-driven, to help the clinician manage these high-risk infections.

Practice Guideline Impact

• Incision and drainage remains the primary treatment for simple cutaneous abscesses. Antibiotic coverage should be reserved for patients with severe infection, immunocompromise, or other risk factors for poor outcome.
• For simple cellulitis, coverage with a beta-lactam antibiotic is generally adequate. Purulent cellulitis is likely due to MRSA, and outpatients should be treated with appropriate antibiotics.
• MRSA is an uncommon cause of severe community-acquired pneumonia (CAP). Empiric therapy for MRSA is recommended only in patients who require intensive care unit (ICU) admission, have necrotizing or cavitary infiltrates, or empyema.
• Weight-based dosing of vancomycin is recommended, using 15-20 mg/kg/dose in adult patients with normal renal function.
• Prompt surgical debridement/drainage of the infectious source is recommended, regardless of whether the source is known to be MRSA.