235 Exposure to resistant fungi across working environments

Widespread use of antifungal agents in the environment and in clinical settings can facilitate selection for resistant fungi. In recent years, antifungal resistance has become an emerging health concern and resistant variants of previously susceptible species are increasingly reported. At present, little is known about the occupational exposure to resistant fungi in working environments. The purpose of this study was to assess the occurrence of fungi resistant to first-line treatment drugs across different working environments. A retrospective study was performed on a unique collection of personal exposure samples, obtained over a twenty-year period from various Danish working environments, including food production, agriculture, waste management, biofuel plants, and health care facilities. Samples were cultivated at 37° C and fungal colonies were identified using MALDI-TOF MS. species classified as risk group 2 organisms, were selected for resistance testing against Itraconazole, Voriconazole, Posaconazole, and Amphotericin B. Assessment of the overall fungal exposure showed high variation between working environments, with the highest exposure levels found in biofuel plants, greenhouses and grass seed production. More than 500 fungal isolates were tested for resistance, the majority of which belonged to species of Aspergillus. Acquired resistance to one or more antifungal drugs was found in 46 isolates, with the highest prevalence of resistance among isolates of Aspergillus niger. In the forthcoming period, resistant isolates will undergo DNA sequencing to elucidate the mechanism and origin of resistance. Furthermore, sequencing will enable the identification of cryptic species, which can have distinct susceptibility patterns, and thus are important to differentiate.