Empiric therapy for VAP without risk factors for antibiotic-resistant organisms and high mortality (mechanical ventilation for pneumonia or septic shock), in an institution where MRSA incidence is < 10% to 20% (of S aureus isolates) and P aeruginosa resistance is < 10% for commonly used empiric antipseudomonal antibiotics, could include any one of the following: Piperacillin / tazobactam Cefepime Levoﬂoxacin Imipenem Meropenem Doses depend on renal function (see table Usual Doses of Commonly Prescribed Antibiotics).