Optimizing therapy for MRSA pneumonia

With its remarkable armamentarium of resistance and virulence factors, Staphylococcus aureus has emerged as a dominant pathogen causing pneumonia of all classifications. Rates of methicillin resistance are increasing as clinicians struggle to find ways to prevent the acquisition of methicillin-resistant Staphylococcus aureus (MRSA) and to effectively treat MRSA pneumonia. Community-associated MRSA has been identified as an important subset of MRSA with unique characteristics. Vancomycin remains a recommended first-line therapy for MRSA pneumonia, but resistance and therapeutic failures with vancomycin are being increasingly reported. Factors associated with vancomycin success or failure have been identified, including the genetics of the MRSA isolate, vancomycin lung penetration, minimum inhibitory concentration, and pharmacokinetic and pharmacodynamic variables. Retrospective analyses suggest that linezolid may provide improved outcomes compared with vancomycin for MRSA pneumonia, but validation in a prospective trial is currently lacking. Other treatment options are limited, but new prospects are being investigated. This paper reviews the epidemiology and pharmacotherapy of MRSA pneumonia.