Patient description: A 17 year old boy complains of vomiting, non-bloody diarrhea, abdominal pain, fever, chills and loss of appetite for the past 3 days. He ate a salad at a restaurant prior to his diarrhea onset. Physical exam was remarkable for pallor, jaundice, and diffuse abdominal tenderness. Lab results were as follows: Hemoglobin: 9.7 g/dL Platelet: 110,000 /cu.mm Creatinine: 3.6 mg/dL blood urea nitrogen (BUN): 73 mg/dL direct bilirubin: 2.4 mg/dL lactate dehydrogenase (LDH): 881 IU/L (normal: 110-265 IU/L) Peripheral blood smear showed a moderate number of schistocytes and helmet cells. Shiga-like toxin-producing E. coli (STEC) stx1/stx2 were found in stools. He has no other underlying disease and he is not on any medications.

Clinical trial eligibility criteria: eligible ages (years): 0.25-17.0,  Intraabdominal Infections Hospitalized males or females 3 months to 17 years of age Able to obtain parental or legal guardian written informed consent and assent from subjects as applicable by local laws and regulations Expected duration of treatment with antibiotics is a minimum of 3 days administered IV, for a total of 5 to 14 days administered IV or IV followed by PO If the subject is a female of child-bearing potential she must have a negative pregnancy test at the screening visit or be capable of practicing an adequate method of contraception, and agree to continue the same method for 1 month following the TOC visit. Lactating subjects are not to be included Subjects may be enrolled upon a surgically (laparotomy, laparoscopy, or percutaneous drainage) confirmed cIAI revealing at least one of the following Gross peritoneal inflammation with purulent exudate within the abdominal cavity Intra-abdominal abscess Macroscopic intestinal perforation with diffuse peritonitis OR Subjects may be enrolled on the basis of a suspected cIAI, which must be supported with radiological evidence (ultrasound, abdominal plain films, computed tomography [CT], magnetic resonance imaging [MRI]) of gastrointestinal perforation or localized collections of potentially infected material and at least one of the following Symptoms referable to the abdominal cavity (eg, anorexia, nausea, vomiting or pain)  Presumed spontaneous bacterial peritonitis All pancreatic processes including pancreatic sepsis, peripancreatic sepsis, or an cIAI secondary to pancreatitis Early acute or suppurative (nonperforated) appendicitis unless there is evidence of an abscess or peritoneal fluid containing pus and micro-organisms suggestive of regional contamination Infections originating from the female genital tract Known severe immunosuppression. Subjects with known mild immunosuppression (eg, Type I or II diabetes mellitus, trauma, or absolute neutrophil count [ANC] between 1000 and 1500 cells/mm3) may be enrolled Congenital or documented acquired QT prolongation Receiving concomitant treatment with QT prolonging drugs History of tendon disease/disorder related to quinolone treatment Pathogenic organisms suspected or identified (eg, Pseudomonas) which are resistant to any of the study drugs Abnormal musculoskeletal findings at baseline assessment; or chronic musculoskeletal disease (eg, juvenile rheumatoid arthritis); or chronic illness with high risk for chronic or recurrent arthritis or tendinitis (eg, cystic fibrosis, chronic inflammatory bowel disease)