Aspergillus species causing invasive fungal disease in Queensland, Australia

Abstract Background:Aspergillus species are important causes of invasive fungal disease, particularly among those with an impaired immune system. Increasing reports have revealed a rising incidence of antifungal drug resistance among Aspergillus spp., particularly among cryptic species. Understanding local antifungal susceptibility patterns is paramount to delivering optimal clinical care. Methods:Aspergillus spp. recovered from clinical specimens between 2000 to 2021 from Pathology Queensland were collected. All Aspergillus spp. that underwent antifungal susceptibility testing were recorded and included in the study. Pathology Queensland services all public healthcare facilities in Queensland, Australia. Results:236 Aspergillus spp. were identified from clinical specimens during the study period. The most frequent species identified were Aspergillus fumigatus complex (n=119), Aspergillus flavus (n=35), Aspergillus terreus (n=32) and Aspergillus niger (n=29). Overall, MIC50/90 values for voriconazole, posaconazole, itraconazole, and isavuconazole were 0.25/1, 0.25/0.5, 0.25/0.5, and 0.5/2 mg/L respectively. Echinocandins demonstrated low MIC values overall with micafungin and anidulafungin both having an MIC50/90 of 0.015/0.03 mg/L. A total of 15 cryptic species were identified; high triazole MIC values were observed with a voriconazole MIC50/90 of 2/8 mg/L. From 2017 to 2021 we observed an increase in incidence of isolates with high voriconazole MIC values. There was no difference in voriconazole MIC values between Aspergillus spp. acquired in North Queensland when compared to Southeast Queensland, AustraliaConclusion:Increasing reports of antifungal resistance among Aspergillus spp. is concerning and warrants further investigation both locally and worldwide. Active surveillance of both the emergence of different Aspergillus spp. and changes in antifungal susceptibility patterns over time is crucial to informing clinicians and treatment guidelines.