Intra-abdominal infections are often polymicrobial, and include aerobic as well as anaerobic bacteria. Antibiotics used in intra-abdominal infections should aim to cover organisms such as Enterobacteriaceae and Bacteroides fragilis, which are the commonest organisms known to cause such infections. Combinations of a third-generation cephalosporin, an aminoglycoside and metronidazole are often used to treat such infections in surgical settings. An alternative to such combinations is the use of a beta lactam - beta lactamase inhibitor combination. Magnex (cefoperazone- sulbactam) is one such combination, which has been shown to be as effective as a standard multidrug regimen such as gentamicin and clindamycin in the management of intra-abdominal infections. The combination of ceftazidime, amikacin and metronidazole has been chosen as a comparator regimen because of its broad coverage of Gram-negative and anaerobic organisms found in such conditions.

Inclusion Criteria:

• Male or female subjects aged greater or equal to 12 years
• Intra-abdominal infection documented by laparotomy or laparoscopy or percutaneous aspiration within 24 hours prior to screening
• Presence of at least three of the following five indicators consistent with intra-abdominal infections (Fever, leucocytosis, abdominal symptoms, abdominal signs, radiological evaluation)
• Written informed consent obtained

Exclusion Criteria:

• Rapidly progressive illness or critically ill subjects
• Pregnant or lactating women, or women of childbearing potential not using an effective method of contraception.
• Treatment with a presumably effective systemic antimicrobial agent for >24 hours within a 72 hour period prior to study entry unless the subject did not sufficiently respond to the treatment (as judged by the investigator)