A 28-year-old man from rural Maharashtra presents with a 6-month history of progressive back pain and constitutional symptoms (fever, night sweats, weight loss). On examination, he has kyphotic deformity of the thoracic spine and a palpable paravertebral abscess. MRI shows destruction of T5 and T6 vertebral bodies with anterior wedging, loss of disc space height, and epidural involvement causing cord compression. Chest X-ray reveals apical infiltrates. Which of the following is the most appropriate immediate management?