Pivotal Study in VAP Suspected or Confirmed to be Due to Pseudomonas Aeruginosa

Key Inclusion Criteria: * Subject has received mechanical ventilation for at least 48h at the time of the randomisation * Acute Physiology and Chronic Health Evaluation (APACHE) of 8 to 30, inclusive, within 24h prior to randomization * Presence of new or progressive infiltrate on chest X-ray * Presence of clinical criteria consistent with VABP * High probability of VABP caused by Pseudomonas aeriginosa Key Exclusion Criteria: * Known or suspected community-acquired bacterial pneumonia or viral, fungal, or parasitic pneumonia * Known hypersensitivity or contra-indications to beta-lactam antibiotics, aminoglycosides, quinolones, colistin, or subjects with a clinically significant history of anaphylactic reaction * Severe liver or renal impairment * Women who are pregnant or nursing, or who are of chilbearing potential and unwilling to use acceptable method of birth control