Table 1 Enrollment criteria

Men and non-pregnant, non-lactating women ≥18 years of age who required a surgical procedure for a complicated intra-abdominal infection (cIAI)

cIAI defined as the following:

An intra-abdominal abscess (including liver and spleen) that developed in a postsurgical patient after receiving standard antibacterial therapy (i.e., at least 48 hours, but not more than 5 days of antibiotics);

Appendicitis complicated by perforation and/or a periappendiceal abscess;

Perforated diverticulitis complicated by abscess formation or fecal contamination;

Complicated cholecystitis with evidence of perforation or empyema; perforation of a gastric or duodenal ulcer with symptoms exceeding 24 hours;

Purulent peritonitis or peritonitis associated with fecal contamination;

Perforation of the large or small intestine with abscess or fecal contamination, or traumatic bowel perforation with symptoms lasting at least 12 hours before an operation

Preoperative suspicion of a diagnosis of spontaneous bacterial peritonitis, simple cholecystitis, gangrenous cholecystitis without rupture, simple appendicitis, acute suppurative cholangitis, pancreatic abscess, or infected necrotizing pancreatitis;

Acute Physiologic and Chronic Health Evaluation (APACHE) II score greater than 30;

Surgical procedure requiring that fascia or deep muscular layers be left open or expectation of planned abdominal re-exploration either in or out of the operating room;

Use of immunosuppressive therapy that would decrease the patient's ability to eradicate the infection, including use of high-dose corticosteroids (e.g., 40 mg or more of prednisone or an equivalent per day for more than 3 weeks before randomization) or known diagnosis of acquired immunodeficiency syndrome;

Current intra-abdominal infection known to be caused by one or more bacterial isolates not susceptible to either of the study drugs (e.g., P. aeruginosa, Proteus mirabilis);

Active or treated leukemia or systemic malignancy that requires chemotherapy, immunotherapy, radiation therapy, or antineoplastic therapy within the 3 months before enrollment, or any metastatic malignancy to the abdomen with life expectancy < 6 months;

Presence of any uncontrolled central nervous system disease;

Significant hepatic disease (i.e., aspartate aminotransferase [AST] or alanine aminotransferase [ALT] level > 10 times the upper limit of normal [ULN] or total bilirubin value > 3 times the ULN) or acute hepatic failure or acute decompensation of chronic hepatic failure;

Significant renal disease (i.e., calculated creatinine clearance < 41 mL/min/1.73 m² after adequate hydration);

Neutropenia with absolute neutrophil count < 1000 mm³ (however, neutrophil counts as low as 500 cells/mm³ permitted if secondary to the acute infectious process);

Concomitant treatment with ganciclovir