There has been a welcome increase in the number of agents available for the treatment of methicillin-resistant Staphylococcus aureus (MRSA).
Vancomycin remains an acceptable treatment option, with moves toward individualized dosing to a pharmacokinetic/pharmacodynamic (PK/PD) target. Numerous practicalities, however, would need to be resolved before implementation.
Lipoglycopeptides as a class show excellent in vitro potency. Their long half-lives and complex PKs may preclude these agents being used in
critically ill patients. Anti-MRSA
cephalosporins provide great promise in the treatment of MRSA. These agents, despite broad-spectrum activity, should be reserved for patients with MRSA
infections as it is likely that usage will be associated with increased rates of resistance.
Daptomycin is currently the only
antibiotic to have shown noninferiority to
vancomycin in the treatment of MRSA
bacteremia. The results of an open-labeled trial to address the superiority of
daptomycin compared with
vancomycin in reduced
vancomycin susceptibility
infections are eagerly anticipated. No drug to date has shown superiority to
vancomycin in the treatment of MRSA
infections with the possible exception of
linezolid in
hospital-acquired pneumonia (HAP), making
linezolid an important option in the treatment of MRSA-proven HAP. Whether these strengths and features are agent or class specific are unclear but will likely be answered with the marketing of
tedizolid. There are insufficient data to recommend either
quinupristin/dalfopristin or
tigecycline, as first line in the treatment of severe MRSA
infections. These agents however remain options in patients with no other alternatives.