LAUSR

Background The recent increase in cases of azole-resistant Aspergillus fumigatus (AR Af ) infections is a major clinical concern owing to its treatment limitations. Patient-derived AR Af occurs after prolonged azole treatment in patients with aspergillosis and involves various cyp51A point mutations or non -cyp51A mutations. The prognosis of patients with chronic pulmonary aspergillosis (CPA) with patient-derived AR Af infection remains unclear. In this study, we reported the case of a patient with AR Af due to HapE mutation, as well as the virulence of the isolate. Case presentation A 37-year-old male was presented with productive cough and low-grade fever. The patient was diagnosed with CPA based on the chronic course, presence of a fungus ball in the upper left lobe on chest computed tomography (CT), positivity for Aspergillus -precipitating antibody and denial of other diseases. The patient underwent left upper lobe and left S6 segment resection surgery because of repeated haemoptysis during voriconazole (VRC) treatment. The patient was postoperatively treated with VRC for 6 months. Since then, the patient was followed up without antifungal treatment but relapsed 4 years later, and VRC treatment was reinitiated. Although an azole-resistant isolate was isolated after VRC treatment, the patient did not show any disease progression in either respiratory symptoms or radiological findings. The AR Af isolated from this patient showed slow growth, decreased biomass and biofilm formation in vitro, and decreased virulence in the Galleria mellonella infection model compared with its parental strain. These phenotypes could be caused by the HapE splice site mutation. Conclusions This is the first to report a case demonstrating the clinical manifestation of a CPA patient infected with AR Af with a HapE splice site mutation, which was consistent with the in vitro and in vivo attenuated virulence of the AR Af isolate. These results imply that not all the AR Af infections in immunocompetent patients require antifungal treatment. Further studies on the virulence of non- cyp51A mutations in AR Af are warranted.