A 45-year-old man presents to his general practitioner with a 3-day history of fever, productive cough with green sputum and right-sided pleuritic chest pain. He is otherwise healthy with no significant comorbidities. Examination shows temperature 38.4 °C, respiratory rate 20 breaths/min, heart rate 88 beats/min, blood pressure 128/76 mmHg and oxygen saturation 97% on room air. Chest auscultation reveals localised crackles at the right base and chest X-ray confirms a right lower lobe pneumonia. His CURB-65 score is 0 and he is well enough for outpatient management. According to Australian Therapeutic Guidelines, which is the most appropriate initial empirical oral antibiotic regimen?