Ventilator-associated pneumonia (VAP) is a commonplace complication of intensive care patients ventilated for longer than 48 hours. Methicillin-resistant Staphylococcus aureus (MRSA) is the cause of late onset VAP in up to about 30% of cases in US hospitals. Ineffective treatment of MRSA VAP clearly leads to prolonged mechanical ventilation and is probably associated with higher mortality. The purpose of this protocol is to directly compare linezolid and vancomycin specifically for MRSA VAP.