Ultrasound — Loculated Pleural Empyema with Septations

A 58-year-old man with poorly controlled diabetes and recent aspiration pneumonia presents with persistent fever (39.2°C), productive cough, and pleuritic chest pain despite 10 days of ceftriaxone and azithromycin. Chest X-ray shows a left-sided pleural effusion that does not layer on lateral decubitus film. Ultrasound of the chest reveals the structure marked **A** — a complex pleural collection with multiple internal hyperechoic septations dividing the fluid into distinct loculations, with underlying left lower lobe consolidation. Diagnostic thoracentesis yields turbid fluid with pH 7.05, glucose 32 mg/dL, and positive Gram stain for gram-positive cocci. Which of the following is the MOST appropriate next step in management?