How to Work Up a Cavity Lung Lesion?

Today's consult question is about recommendations for working up a cavitary lung lesion. The patient has been admitted for two weeks of fever, a sthenia, productive cough, and exceptional dyspnea. Her past medical history is remarkable for bilateral lung transplantation since months ago due to severe emphysema. She is CMB donor positive, recipient negative, and is currently on prophylaxis.