Study to Assess the Efficacy and Safety of Meropenem and Pralurbactam in CIAI

Inclusion Criteria: * Male or female participants ≥18 and ≤75 years of age. * Diagnosed or highly suspected cIAI. * Evidence of a systemic inflammatory response with at least one of the following:a. Fever ( temperature ≥ 38°C); b. hypotension (systolic blood pressure \< 90 mmhg); c. abdominal pain; d. nausea and/or vomiting; e. physical examination found abdominal mass; f. mental state change; g. other circumstances. * Female subjects must meet the following conditions: a. menopause for at least 1 year, or b. Sterilization has been performed, or C. Those who are fertile must meet the following conditions at the same time: the random pre-blood/urine pregnancy test is negative, effective contraceptive measures are taken during the study period and within 30 days after the last application of experimental drugs, and eggs are not donated, and they are not breastfeeding. * Male subjects are willing to take effective contraceptive measures and not donate sperm during the study period and within 30 days after the last application of experimental drugs. * Understand and abide by the research procedures and methods, voluntarily participate in this research, and sign an informed consent form . Exclusion Criteria: * Allergic to any carbapenem, cephalosporin, penicillin, metronidazole disodium phosphate, other beta-lactam drugs or other beta-lactamase inhibitors and their auxiliary materials. * Non-complicated abdominal infection (infection is limited to abdominal organs), such as simple appendicitis and simple cholecystitis. * Abdominal wall infection or abscess (infection has not spread into abdominal cavity). * The creatinine clearance rate in the screening period is ≤50mL/min. * The estimated survival time is less than 4 weeks. * Those who have a history of drug abuse or drug abuse within 6 months before screening. * Those who participated in other clinical trials within 28 days before randomization and used any test drugs or medical devices. * Any physiological or psychological disease or condition that may increase the risk of the experiment, affect the compliance of the subject with the protocol or affect the completion of the experiment as judged by the researcher. * Subjects are directly related persons who participated in this research.