• Microbiological response at posttherapy will be based on eradication or persistence of the pathogen(s) isolated at admission
  

• Clinical response at posttherapy will be based on the comparison of posttherapy signs/symptoms and radiological findings reported at posttherapy compared to those reported at admission. Clinical and microbiologic response at poststudy.
  

Despite advances in prevention and treatment, hospital-acquired pneumonia remains a significant problem as the second most common infection acquired in the hospital and the most deadly (20%-50% of patients who acquire pneumonia while in the hospital die from complications of pneumonia). Levofloxacin has been shown in clinical trials to be effective against a number of different bacteria, including those found to be common and uncommon causes of pneumonia. This multicenter, open-label study evaluates the safety and effectiveness of levofloxacin as compared with imipenem/cilastatin, another type of antibiotic treatment, in patients with pneumonia acquired in the hospital. Patients receive treatment for a total of 7-15 days, initially with levofloxacin or imipenem/cilastatin, administered slowly through a vein. If patients respond positively to either drug, treatment may be changed to levofloxacin or ciprofloxacin (if initially treated with imipenem/cilastatin), to be taken by mouth. Certain additional drugs may be added if needed to treat pneumonia caused by certain bacteria. Patients showing signs of improvement continue in the study, with assessments 5-7 days (posttherapy visit) and 28-32 days after completion of the study drug (poststudy visit). Effectiveness is assessed by measuring the ability of the study drug to eliminate bacteria causing pneumonia and to reduce the signs and symptoms of pneumonia. Chest x-rays and laboratory tests for bacteria are performed throughout the study and patients' severity of disease is rated according to the Acute Physiology And Chronic Health Evaluation (APACHE) scale. Safety evaluations (incidence of adverse events, physical examinations, laboratory tests) are performed throughout the study. Blood samples are drawn from patients receiving levofloxacin to determine the concentration of levofloxacin in the blood. The study hypothesis is that levofloxacin is at least as effective as imipenem/cilastatin in treating hospital-acquired pneumonia and is generally well-tolerated.

Levofloxacin 750 mg administered through a vein once daily or imipenem/cilastatin 500mg-1 gram every 6-8 hours. Upon improvement, patients may transition to levofloxacin 750mg by mouth once daily or ciprofloxacin 750mg by mouth twice daily for 7-15 days.