A 30-year-old man presents with coughing up blood and sputum. There is no associated dyspnea, fever, or pleuritic chest pain. His past medical history is significant for recurrent pneumonias and a chronic cough productive of foul-smelling purulent sputum. The sputum production is usually worse when lying down and in the morning. He quit smoking 5 years ago and started when he was 18 years old. On physical examination, he appears chronically ill with clubbing of the fingers. Wet inspiratory crackles are heard at the lung bases posteriorly. CXR shows scaring in the right lower lobe, which on chest CT scan is identified as airway dilatation, bronchial wall thickening, and grapelike cysts. Which of the following is the most likely diagnosis?

---