A 42-year-old man presents with fever, productive cough and pleuritic chest pain for 2 days. He is otherwise well, saturating 96 percent on room air, respiratory rate 20 breaths per minute and BP 120/70 mmHg. Chest examination reveals right lower lobe crackles. He can be safely managed as an outpatient. According to Australian antibiotic guidelines, what is the most appropriate empirical oral antibiotic regimen?