COVID-19-associated pulmonary aspergillosis: clinical characteristics, species distribution, environmental fungal contamination, and antifungal susceptibility

COVID-19-associated pulmonary aspergillosis (CAPA) is an important secondary fungal complication of severe and critical COVID-19, particularly among patients requiring intensive care. Distinguishing CAPA from Aspergillus airway colonization remains challenging because respiratory isolation of Aspergillus does not necessarily indicate invasive disease. This study aimed to evaluate the burden of CAPA, characterize Aspergillus species distribution, assess antifungal susceptibility, and investigate the role of hospital environmental fungal contamination. This cross-sectional study conducted on hospitalized COVID-19 patients admitted to intensive care units (ICUs). Demographic and clinical data, including underlying risk factors, were collected from medical records. All patients with Aspergillus-positive respiratory or tissue specimens were reassessed at the patient level according to the 2020 ECMM/ISHAM consensus criteria, taking into account clinical and radiological findings and specimen-specific mycological evidence. Aspergillus isolates recovered by culture were identified using molecular methods and tested for antifungal susceptibility. Environmental air sampling was also performed in ICUs. In total, 290 hospitalized COVID-19 patients were included. Aspergillus spp. were isolated from 60 of 290 patients (20.7%). Following patient-level assessment, 54 patients (18.6%) fulfilled the criteria for CAPA, including 3 (5.5%) with proven CAPA, 42 (77.8%) with probable CAPA, and 9 (16.7%) with possible CAPA. Six patients (10.0% of Aspergillus-positive patients) did not fulfill the criteria for CAPA and were classified as having Aspergillus airway colonization. The mean age of CAPA patients was 60.2 ± 12.8 years, and 36 patients (66.7%) were male, with an overall crude in-hospital mortality rate of 42.6%. Molecular identification showed among the 60 Aspergillus isolates, A. flavus as the predominant species (n = 48, 80%), followed by A. fumigatus (n = 9, 15%) and A. terreus (n = 3, 5%). Endotracheal intubation was the most common reported predisposing factor (n = 6, 11.11%). Environmental sampling in the ICU identified 21 fungal isolates, comprising Cladosporium spp. (n = 9), Alternaria spp. (n = 6), Fusarium spp. (n = 3), and Aspergillus niger (n = 3). Antifungal susceptibility testing showed generally low MIC values, with posaconazole (GM MIC 0.07 mg/L; MIC50 0.063 mg/L; MIC90 0.125 mg/L) demonstrating the greatest in vitro activity. The predominance of A. flavus highlights regional variation in Aspergillus species distribution, whereas the detection of multiple airborne fungal genera underscores the importance of environmental surveillance in high-risk hospital settings. Given the lack of strain-level molecular typing, the environmental isolates cannot be considered a demonstrated source of the clinical infections.