Inclusion Criteria:

• Hospitalized men or women >/=18 years of age
• Expected duration of treatment with intravenous antibiotics anticipated to be >/= 5 full days but not exceeding 14 days
• Ability to provide documented and signed written informed consent

• Confirmed or suspected intra abdominal infection defined as follows:

  • For a confirmed intra abdominal infection, a surgical procedure (laparotomy or laparoscopy) must have been performed within 24 hours prior to enrollment and reveal at least one of the following:

    • Gross peritoneal inflammation with purulent exudates (i.e. peritonitis)
    • Intra abdominal abscess
    • Macroscopic intestinal perforation with localized or diffuse peritonitis

• Subjects enrolled on the basis of a suspected intra abdominal infection must have:

  • Radiological evidence [abdominal plain films, computed tomography (CT), magnetic resonance imaging (MRI) or ultrasound] of gastrointestinal perforation or intra-abdominal abscess and the following signs and symptoms:

    • Symptoms referable to the abdominal cavity (e.g. anorexia, nausea, vomiting or pain), lasting for at least 24 hours
    • Tenderness (with or without rebound), involuntary guarding, absent or diminished bowel sounds, or abdominal wall rigidity

  • At least two of the following SIRS criteria:

    • Temperature > 38.0°C rectal or tympanic membrane, or temperature < 36.0°C rectal or tympanic
    • Heart rate > 90/min
    • Respiratory rate > 20/min
    • WBC >12,000 cells/mm3 or < 4,000 cells/ mm3
  • The subject must be scheduled for a surgical procedure (laparotomy or laparoscopy) within 24 hours of enrollment of the study

Exclusion Criteria:

• Known hypersensitivity to quinolones, and/or to carbapenems and/or to any other type of beta lactam antibiotic drugs (e.g. penicillins or cephalosporins), or any of the excipients
• Women who are pregnant or lactating or in whom pregnancy cannot be excluded
• History of tendon disease/disorder related to quinolone treatment
• Known congenital or documented acquired QT prolongation; uncorrected hypokalemia; clinically relevant bradycardia; clinically relevant heart failure with reduced left ventricular ejection fraction; previous history of symptomatic arrhythmias
• Concomitant use of any of the following drugs, reported to increase the QT interval: antiarrhythmics class IA (e.g. quinidine, hydroquinidine, disopyramide) or antiarrhythmics class III (e.g., amiodarone, sotalol, dofetilide, ibutilide), neuroleptics (e.g. phenothiazines, pimozide, sertindole, haloperidol, sultopride), tricyclic antidepressive agents, certain antimicrobials (sparfloxacin, erythromycin IV, pentamidine, antimalarials, particularly halofantrine), certain antihistaminics (terfenadine, astemizole, mizolastine), and others (cisapride, vincamine IV, bepridil, diphemanil)
• Known severe end stage liver disease
• Creatinine clearance </= 30 mL/min/1.73 m2
• Systemic antibacterial therapy administered for more than 24 hours within 7 days of enrollment
• Need for systemic antibacterial therapy with agents other than those described in the study protocol
• Indwelling peritoneal catheter
• Pre existing ascites and presumed spontaneous bacterial peritonitis
• Perforation of the stomach or duodenum, if the duration of perforation is less than 24 hours or if operated on within 24 hours of perforation
• Perforation of the small bowel (excluding the duodenum) or large bowel, if the duration of perforation is less than 12 hours or if operated on within 12 hours of perforation
• All pancreatic processes including pancreatic sepsis, peri-pancreatic sepsis, or an intra abdominal infection secondary to pancreatitis
• Liver and splenic abscess
• Transmural bowel ischemia or necrosis without perforation or established peritonitis or abscess
• Acute and gangrenous cholecystitis without perforation
• Acute cholangitis
• Early acute, suppurative, or gangrenous non-perforated appendicitis
• Subjects requiring antibiotic irrigations of the abdominal cavity or surgical wound
• Treatment with "open abdomen" or marsupialization, or multiple planned re laparotomies
• Infections originating from the female genital tract
• Peri-nephric infections
• Evidence of sepsis with shock requiring the administration of vasopressors for more than 4 consecutive hours
• Known rapidly fatal underlying disease (death expected within 6 months)
• Neutropenia (neutrophil count < 1,000/mL) caused by immunosuppressive therapy or malignancy
• Receiving chronic treatment with known immunosuppressant therapy (including chronic treatment with > 15 mg/day of systemic prednisone or equivalent)
• Subjects known to have AIDS (CD4 count < 200/mL) or HIV seropositives who are receiving HAART (HIV positive subjects may be included. HIV testing is not required for this study protocol)
• Subjects with a malignant or pre malignant hematological condition, including Hodgkin's disease and non-Hodgkin lymphoma (subjects with solid tumor can be included in the study)
• Subjects with a Body Mass Index >/= 45 kg/m2
• Previous enrollment in this study
• Participation in any clinical investigational drug study within the previous 4 weeks