This clinical trial compares the use of moxifloxacin versus ceftriaxone in the treatment of primary pyogenic liver abscess. The trial will include nonpregnant adults presenting with primary liver abscess based on clinical diagnosis and computed tomography. The trial aims to determine whether the use of moxifloxacin can effectively treat primary pyogenic liver abscess and shorten hospitalization. This regimen has the additional benefit of avoiding nephrotoxic agents, such as aminoglycosides, used frequently in treatment of pyogenic liver abscess. Development of antibiotic resistance to colonized bacteria in the gastrointestinal tract will also be evaluated using stool cultures.

Inclusion Criteria:

• Age greater or equal to 20 years.
• Clinical diagnosis of liver abscess, supported by an abdominal CT scan, documenting the presence of liver abscess, in the absence of biliary tract stones (except for gallstones without biliary tract dilatation), biliary tract dilatation and biliary tract tumors. Clinical diagnosis of liver abscess includes symptoms of fever, chills, right upper quadrant abdominal pain or knocking tenderness.
• Read, understood and signed informed consent form.

Exclusion Criteria:

• Presence of septic metastatic infections to the CNS or eye at presentation.
• Cultures positive for an organism resistant to study drugs.
• APACHE II score greater or equal to 20.
• Co-existent disease considered likely to affect the outcome of the study (e.g., biliary tract stones and malignancy).
• Patients with ruptured liver abscess
• Severe hepatic insufficiency (Child-Pugh C) or elevated serum transaminases (GPT) to greater than 5 times the upper limit of normal.
• Patients who are pregnant or lactating.
• Known hypersensitivity to b-lactams or fluoroquinolones.
• Known prolongation of the QT interval.
• Patients with uncorrected hypokalemia.
• Patients receiving class IA (e.g., quinidine, procainamide) or class III (e.g., amiodarone, sotalol) antiarrhythmic agents
• Severe, life-threatening disease with a life expectancy of less than 2 months.
• Pre-treatment with a systemic antibacterial agent for > 24 hours prior to enrollment within 5 days prior to enrollment.
• Participated in any clinical investigational drug study within 4 weeks of screening.
• Previously entered in this study.