The study is contemplating the antibiotic therapy of intraabdominal abscesses. These abscesses are a serious problem in surgical practice. Associated pathophysiologic effects as for example peritonitis may become life threatening or may lead to extended periods of morbidity with prolonged hospitalization.

The objective of the sudy is to evaluate whether the combination of Moxifloxacin and Metronidazole is equivalent to Piperacillin / Tazobactam with regard to clinical outcome and eradication of aerobe and anaerobe pathogens in patients with intra-abdominal abscesses.

The study is an interventional prospective, comparative, open-label, randomised single-centre study. Adult patients with intra-abdominal abscesses matching the criteria to be included will be enrolled in the study and randomised into one of the Groups: 1. Moxifloxacin 400 mg, administered intravenously once daily in combination with Metronidazole 500 mg, administered two times daily intravenously, followed by an oral medication with Moxifloxacin 400 mg once daily and Metronidazole 500 mg twice daily. 2. Piperacillin / Tazobactam 4,5 g administered intravenously three times daily.

Primary study endpoints: Clinical success / failure rate at the Test-of-Cure visit.

Secondary study endpoints: -Bacteriological response at TOC, -Clinical + Bacteriological response at End-of-Treatment-visit, - Course of disease on the basis of clinical and laboratory parameters, -Time to discharge from hospitals, -Duration of hospitalization post-operatively, - safety and tolerability of the study medication, -cost effectiveness of treatment regimes.

Inclusion Criteria:

• Patients who attained full age (18 years) with intra-abdominal abscesses documented by:

A) Laparotomy revealing intra-abdominal abscess or macroscopic gastrointestinal perforation OR

B) Suspected intra-abdominal abscess and scheduled for operation with at least three of the following criteria:

• fever,
• leucocytosis,
• symptoms referable to the abdominal cavity (nausea, pain),
• tenderness with or without rebound / abdominal wall rigidity,
• radiological evidence for abscess or gastrointestinal perforation.

Exclusion Criteria:

• Patients with the following:

  • indwelling peritoneal catheter,
  • presumed spontaneous bacterial peritonits,
  • peripancreatic sepsis or infection secondary to pancreatitis,
  • peptic or traumatic perforation of gastrointestinal tract of < 24 h duration,
  • traumatic perforation of the small or large bowel of < 12h duration,
  • transmural necrosis of the intestine due to acute embolic, thrombotic or obstructive occlusions,
  • acute cholecystitis,
  • appendicitis without perforation or abscess,
  • required open abdomen techniques for management,
  • gynaecological infection,
  • known hypersensivity to any of the study drugs,
  • lifethreatening disease with life expectancy of less than 48 hours,
  • neutropenia with neutrophil count < 1000 cells/µl,
  • receiving chronic treatment with imunosuppressant therapy,
  • HIV-seropositives with CD4 count < 200 cells/µl,
  • end stage hepatic cirrhosis CHILD PUGH C,
  • central or peripheral neuropathy,
  • bradycardia,
  • symptomatic dysrhythmia in medical history,
  • syndromes of QTc prolongation or use of concomittant medicaments reported to increase QT interval,
  • disorder of the electrolyte balance,
  • previous history of tendinopathy with quinolones,
  • previously enrolled in the trial or use of any investigational drug within the previous 30 days