Study Comparing the Safety and Efficacy of Intravenous CXA-201 and Intravenous Meropenem in Complicated Intraabdominal Infections

Inclusion Criteria: * Diagnoses of cIAI. * Subject requires surgical intervention (e.g., laparotomy, laparoscopic surgery, or percutaneous draining of an abscess) within 24 hours of (before or after) the first dose of study drug. Exclusion Criteria: * Simple appendicitis; acute suppurative cholangitis; infected necrotizing pancreatitis; pancreatic abscess; or pelvic infections. * Complicated intraabdominal infection managed by staged abdominal repair (STAR), open abdomen technique including temporary closure of the abdomen, or any situation where infection source control is not likely to be achieved. * Use of systemic antibiotic therapy for IAI for more than 24 hours prior to the first dose of study drug, unless there is a documented treatment failure with such therapy. * Have a concomitant infection at the time of randomization, which requires non-study systemic antibacterial therapy in addition to IV study drug therapy. (Drugs with only gram-positive activity \[e.g., daptomycin, vancomycin, linezolid\] are allowed). * Severe impairment of renal function (estimated CrCl \< 30 mL/min), or requirement for peritoneal dialysis, hemodialysis or hemofiltration, or oliguria (\< 20 mL/h urine output over 24 hours). * The presence of hepatic disease at baseline. * Considered unlikely to survive the 4 to 5 week study period. * Any rapidly-progressing disease or immediately life-threatening illness (including respiratory failure and septic shock). * Have a documented history of any moderate or severe hypersensitivity or allergic reaction to any β-lactam antibacterial (a history of a mild rash followed by uneventful re-exposure is not a contraindication to enrollment), including cephalosporins, carbapenems, penicillins, or ß-lactamase inhibitors, or metronidazole, or nitroimidazole derivatives. * Women who are pregnant or nursing.