• Any other complication [ Time Frame: intraoperatively, postoperatively, at discharge, at 7-days, 1-month, 6-months follow-up ] [ Designated as safety issue: Yes ]
• The total costs of antibiotic therapy [ Time Frame: during hospital stay ] [ Designated as safety issue: No ]

The aim of the study was to compare the activity (efficacy and safety) of Ertapenem administered according to a short treatment for three days versus a short treatment for three days with AS in patients with an community acquired IAI of mild to moderate severity.

The study project is a prospective, randomized controlled investigation. The study will be performed in the Department of Transplant, General and Emergency Surgery of St Orsola-Malpighi University Hospital (Bologna, Italy), a large teaching institution, with the participation of all surgeons who accept to be involved in.

The study is designed and conducted in compliance with the principles of Good Clinical Practice regulations.

The tolerability and efficacy of a 3 days treatment with Ampicillin- Sulbactam (AS 3g x 3/ day i.v.) is compared a 3 days regimen with Ertapenem (1 g/day i.v.). in patients with localized peritonitis with a blinded evaluation of efficacy end points. Evaluation of cure or failure is blinded by use of designated third party individuals who are unaware of the treatment assigned to the patients.

• Drug: Ertapenem
• Drug: Ampicillin-Sulbactam

• Experimental: 3 days regimen with Ertapenem
• Active Comparator: 3 days treatment with Ampicillin-Sulbactam

Inclusion Criteria:

Adult patients ( > 18 years) requiring surgical intervention within 24 hours of diagnosis, for localized IAI infections (i.e extending beyond the organ wall but confined near the hollow viscus, mild to moderate in severity):

• Acute appendicitis: Ruptured or perforated with abscess
• Acute diverticulitis with perforation and/or abscess
• Acute cholecystitis (including gangrenous) with either rupture or perforation
• Acute gastric and duodenal ( > 24 hours) perforation
• Traumatic (> 12 hours) perforation of the intestines
• Secondary peritonitis due to perforated viscus
• Intra-abdominal abscess (including of liver and spleen)

Exclusion Criteria:

• Traumatic bowel perforation requiring surgery within 12 hours
• Perforation of gastroduodenal ulcers requiring surgery within 24 hours
• other intra-abdominal processes in which the primary etiology was unlikely to be infectious.
• Patients lactating or pregnant
• Patients with a history of allergy, hypersensitivity, or any severe reaction to the study antibiotics
• Patients with rapidly progressive or terminal illness;
• Patients with a history or presence of severe hepatic or renal disease (e.g. creatinine clearance < 0.5 ml/min/1.73 m2);
• Patients with a concomitant infection that would interfere with evaluation of response to the study antibiotics.