Azole-resistant Aspergillus fumigatus Containing a 34-bp Tandem Repeat in cyp51A Promoter is Isolated from the...

Azole-resistant strains of Aspergillus fumigatus containing a tandem repeat in the cyp51A promoter and amino acid substitution(s) have been isolated in the environment worldwide; however, this type of resistant strain had never been isolated from the environment in Japan. Our previous study indicated that an azole-resistant A. fumigatus strain OKH50 containing a 34-bp tandem repeat in cyp51A promoter with L98H substitution in Cyp51A was isolated from a patient in Obihiro of Hokkaido, Japan. In this study, we collected azole-resistant Aspergillus spp. by air sampling from the environment in Japan. One Aspergillus-like colony was isolated from one of 10 sampling sites surveyed. The strain Env1 was confirmed as A. fumigatus by nucleotide sequencing and possessed a 34-bp tandem repeat in the promoter region of cyp51A with L98H substitution in Cyp51A. A. fumigatus Env1 has the identical short tandem repeat pattern with the OKH50 strain, indicating that these strains are closely related with each other. Additionally, the short tandem repeat pattern is closely related to Danish and Iranian environmental isolates, suggesting that azole-resistant strains have crossed transnational boundaries and are now present in Japan, and therefore, further analysis throughout Japan is required to determine the distribution of this type of azole-resistant A. fumigatus.