Aspergillus species in Iceland: species distribution and cyp51A mutation testing in a 7.5-year clinical isolate collection

Abstract

Introduction.Among challenges in diagnosing and treating aspergillosis are Aspergillus species identification, which can inform therapeutic choices, and detection of antifungal resistance. Increasing rates of triazole resistance have been reported for the most common species, Aspergillus fumigatus. Methods.A collection of clinical Aspergillus isolates cultured during 2014-2021, previously identified morphologically, were tested with the AsperGenius qPCR-kit for identification of A. fumigatus and Aspergillus flavus and the presence of a cyp51A mutation encoding azole resistance (TR34/L98H and Y121F/T289A); other species were identified with calmodulin sequencing. Results.Identification of the 312 isolates (224 patients) tested revealed 19 species in nine Aspergillus sections. Rare or cryptic species were identified in 48 isolates (44 patients). Thirty-one isolates had been assigned an incorrect species name when initially cultured. The TR34/L98H and Y121F/T289A mutations were not found in any of the 202 A. fumigatus isolates tested. Discussion.In this first study on clinical Aspergillus isolates in Iceland the proportion of cryptic and rare species was on par with findings from other countries. In contrast, unlike other studies we did not find the most common azole resistance-related mutations in A. fumigatus, possibly due to the absence of significant environmental antifungal pressure in the local agriculture.