Antibiotics for Klebsiella Liver Abscess Study

Inclusion Criteria 1. Inpatient at time of enrollment 2. Age \>= 21 years 3. Computed tomography (CT) or ultrasound (US) within the preceding 7 days suggestive of a liver abscess, as defined by presence of one or more focal areas of hypo- or hyper-attenuation within the liver 4. Klebsiella pneumoniae isolated from abscess fluid or blood collected within the preceding 7 days 5. Able and willing to give informed consent Exclusion Criteria All subjects meeting any of the following exclusion criteria at baseline will be excluded from participation: 1\) Polymicrobial abscess - additional organisms isolated from blood or abscess fluid within the preceding 7 days 2a) Klebsiella pneumoniae resistant to Ceftriaxone AND Ertapenem 2b) Klebsiella pneumoniae resistant to Ciprofloxacin AND Cotrimoxazole 3) On effective\* IV antibiotics \> 7 days 4a) Hypersensitivity to cephalosporins AND carbapenems; as defined by history of rash, urticaria, angiodema, bronchospasm or circulatory collapse following prior administration. 4b) Hypersensitivity to fluoroquinolones AND sulpha drugs; as defined by history of rash, urticaria, angioedema, bronchospasm or circulatory collapse following prior administration. 4c) History of penicillin anaphylaxis (angioedema, bronchospasm or circulatory collapse). Subjects with a history of only rash or urticaria or unknown reaction to penicillin can be included. 5\) Inability to take oral medications for any reason 6) Severe sepsis or septic shock defined as unresolved hypotension (MAP\<70) or tachycardia (HR\>110), or requirement of inotropic support or ventilation at time of eligibility. Should the subject's hypotension or tachycardia subsequently resolve, and they cease to require inotropes and ventilation within 7 days, they may be reconsidered for eligibility. 7\) Established endophthalmitis at time of screening (patients with visual symptoms should have ophthalmology review prior to enrollment) 8) Established central nervous system abscess at time of screening (patients with focal neurology should have CT head prior to enrollment) 9) Women who are pregnant or breastfeeding 10) Inability to obtain consent from subject 11) Patients on tizanidine or theophylline 12) Patients on concomitant drugs that can result in prolongation of the QT interval (e.g., class IA or class III antiarrhythmics) or with risk factors for torsade de pointes (e.g., known QT prolongation, uncorrected hypokalemia) 13) Patients whose K. pneumoniae tests resistant to ciprofloxacin, and those with contraindications to ciprofloxacin will be tested for G6PD deficiency, and excluded if deficient 14) Severe immunocompromise (e.g., active leukemia or lymphoma, generalized malignancy, aplastic anemia, solid organ transplant, bone marrow transplant within 2 years of transplantation, or transplants of longer duration still on immunosuppressive drugs or with graft-versus-host disease, congenital immunodeficiency, current radiation therapy, HIV/AIDS with CD4 lymphocyte count \<200 and patients or on immunosuppressant medications) 15) Creatinine clearance \<15 ml/min \*defined as antibiotics to which the Klebsiella pneumoniae isolate in blood or abscess fluid is susceptible