Inclusion Criteria:

• Patients aged 18 years or above
• All of the following signs and symptoms of pneumonia:
• Fever (core/ rectal/ tympanic temperature >/= 38.5°C or axillary/ oral/ cutaneous temperature >/= 38.0°C) or hypothermia (core/ rectal/ tympanic temperature </= 35.5°C or axillary/ oral/ cutaneous temperature </= 35.0°C)
• White blood cell (WBC) count > 10,000/µL, or >/= 15% immature neutrophils (bands), regardless of the peripheral WBC count, or total WBC count < 4,500/µL
• The presence of at least 2 of the following symptoms:
• Cough
• Purulent sputum production
• Dyspnoea or tachypnoea (respiratory rate > 20 breaths/minute)
• Rigors and/or chills
• Chest pain
• Auscultatory findings on pulmonary examination of rales/crackles and/or evidence of pulmonary consolidation AND
• Radiological evidence of (an) infiltrate(s) consistent with bacterial pneumonia at baseline or within 24 hours following enrolment
• Fine score >/= 71 (i.e. Pneumonia PSI risk Class III, IV or V, requiring hospitalisation for the treatment of CAP)
• Written informed consent obtained from the patient or a next-of-kin

Exclusion Criteria:

• Known hypersensitivity to fluoroquinolones, or other quinolones, and/or to beta-lactams, or any of the excipients
• Female patients who are pregnant or lactating
• History of tendon disease/disorder related to quinolone treatment
• Known congenital or documented-acquired QT prolongation; concomitant use of drugs, reported to increase the QT interval; uncorrected hypokalaemia; clinically relevant bradycardia; clinically relevant heart failure with reduced left-ventricular ejection fraction; previous history of symptomatic arrhythmias
• History of epilepsy
• Known glucose-6-phosphate dehydrogenase deficiency
• Known severe impaired liver function (i.e. Child Pugh C), (refer to Section 10.4 for definition) or transaminases increase > 5 fold ULN
• Hospitalisation for > 48 hours before developing pneumonia, or discharge from hospital < 30 days prior
• Systemic antibacterial therapy for more than 24 hours within 14 days of enrolment
• Patients requiring concomitant systemic antibacterial agents
• Known structural lung disease (e.g. cystic fibrosis, bronchiectasis, or lung cancer), or other known conditions (e.g. malnutrition) predisposing to infection with nosocomial-like organisms such as Pseudomonas aeruginosa
• Lung abscess, pleural empyema, risk factors for aspiration pneumonia (e.g. recent stroke, head injury, dementia)
• Known rapidly fatal underlying disease (death expected within 6 months)
• Known or suspected active tuberculosis or endemic fungal infection
• Neutropenia (neutrophil count < 1,000/µL) caused by immunosuppressive therapy or malignancy
• Patients known to have AIDS (CD4 count < 200/µL) or HIV-seropositive patients receiving HAART
• Previous enrolment in this study
• Participation in any clinical investigational drug study within the previous 4 weeks
• Patient with pre-terminal renal failure (creatinine clearance < 10 mL/min) and patients undergoing haemodialysis