Failure of voriconazole therapy due to acquired azole resistance in Aspergillus fumigatus in a kidney transplant recipient with chronic necrotizing aspergillosis.

Invasive aspergillosis (IA) affects the lungs and disseminates mostly in patients with neutropenia and/or patients who are receiving immunosuppressive and steroid therapies. Despite progress in the diagnosis of and therapy for IA, it is still characterized by a high mortality rate. Currently, voriconazole is considered as the standard therapy for IA. Over recent years, triazole-resistant Aspergillus fumigatus isolates have emerged in the environment due to the use of fungicidal agricultural products, with the risk of developing IA related to a resistant isolate. However, resistance may also develop in patients who are undergoing long-term triazole therapy, particularly in the setting of chronic forms of pulmonary aspergillosis. Herein we describe a kidney transplant recipient who failed to respond to voriconazole therapy due to acquired resistance secondary to the appearance of a de novo mutation (Y121F) in the cyp51A gene during chronic necrotizing pulmonary aspergillosis. The infecting isolate acquired voriconazole resistance in 8 months despite plasma concentrations within the recommended range of the drug, necessitating lobectomy in association with a new antifungal strategy consisting of liposomal amphotericin and caspofungin with a good outcome over 36 months.