Breakthrough Tracheobronchial Aspergillosis Caused by Aspergillus calidoustus and Aspergillus niger in a Lung Transplant Recipient Despite Combined Antifungal Prophylaxis.

Aspergillus niger and Aspergillus calidoustus are relatively uncommon pathogens that could cause invasive disease, especially in immunocompromised patients. We present the case of a 61-year-old male with a history of idiopathic pulmonary fibrosis who was admitted to our hospital for a unilateral lung transplant that was performed without complications; despite voriconazole prophylaxis, he developed tracheobronchial aspergillosis, caused by A. niger and A. calidoustus-a species difficult to identify due to its close microbiological and genetic resemblance to other Aspergillus species. Molecular diagnostic methodologies are indispensable for the precise identification of cryptic Aspergillus species, a necessity emphatically demonstrated by this specific clinical presentation. The reliance upon these tools, in contrast to conventional phenotyping, is crucial for guiding appropriate and potentially life-saving antifungal therapeutic interventions in critical scenarios like lung transplantation.