A 35-year-old previously well man presents with fever, pleuritic chest pain and cough productive of green sputum for 3 days. He has a temperature of 38.6 °C, respiratory rate 20 breaths per minute, blood pressure 128/76 mmHg and oxygen saturation 96 percent on room air. Chest auscultation reveals right lower lobe crackles and chest X-ray shows a right lower lobe consolidation. CURB-65 score is 0. What is the most appropriate empirical antibiotic treatment in the community?