Nosocomial methicillin-resistant staphylococcus aureus (MRSA) pneumonia: linezolid or vancomycin? - Comparison of pharmacology and clinical efficacy

The incidence of nosocomial pneumonia involving methicillin-resistant Staphylococcus aureus strains (MRSA) is on the rise worldwide. For years, vancomycin has been used as the drug of choice in the treatment of MRSA infections and was recommended as such by clinical guidelines. There is growing evidence that vancomycin, despite low resistance rates is a suboptimal therapeutic option in critically ill patients, particularly in patients with pneumonia. Disadvantages of vancomycin are i) slow bactericide action, ii) poor penetration into pulmonary tissue, iii) the globally slowly increasing vancomycin MICs ("creep") that result in increased clinical failure despite being susceptible according to defined break points and iv) nephrotoxicity. In contrast to other novel antibiotics with MRSA activity, Linezolid is currently approved for the treatment of nosocomial pneumonia in the USA and Europe. Several studies have compared vancomycin with linezolid for nosocomial pneumonia with conflicting results. This review compares both substances regarding pharmacodynamics, resistance, safety and clinical efficacy and discusses preliminary data of the ZEPHyR study. This study compared linezolid versus vancomycin in patients with proven MRSA pneumonia and was the largest trial ever conducted in this population.