Environmental Study of Azole-Resistant Aspergillus fumigatusand Other Aspergilli in Austria, Denmark, and Spain

ABSTRACTA single mechanism of azole resistance was shown to predominate in clinical and environmental Aspergillus fumigatusisolates from the Netherlands, and a link to the use of azoles in the environment was suggested. To explore the prevalence of azole-resistant A. fumigatusand other aspergilli in the environment in other European countries, we collected samples from the surroundings of hospitals in Copenhagen, Innsbruck, and Madrid, flowerbeds in an amusement park in Copenhagen, and compost bags purchased in Austria, Denmark, and Spain and screened for azole resistance using multidish agars with itraconazole, voriconazole, and posaconazole. EUCAST method E.DEF 9.1 was used to confirm azole resistance. The promoter and entire coding sequence of the cyp51Agene were sequenced to identify azole-resistant A. fumigatusisolates. A. fumigatuswas recovered in 144 out of 185 samples (77.8%). Four A. fumigatusisolates from four Danish soil samples displayed elevated azole MICs (8%), and all harbored the same TR/L98H mutation of cyp51A. One A. lentulusisolate with voriconazole MIC of 4 mg/liter was detected in Spain. No azole-resistant aspergilli were detected in compost. Finally, A. terreuswas present in seven samples from Austria. Multi-azole-resistant A. fumigatusis present in the environment in Denmark. The resistance mechanism is identical to that of environmental isolates in the Netherlands. No link to commercial compost could be detected. In Spain and Austria, only Aspergillusspecies with intrinsic resistance to either azoles or amphotericin B were found.