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Background: Mutations in cyp51A gene are known as main mechanisms of azole resistance in Aspergillus fumigatus, whereas azole‐susceptible strains also carry cyp51A mutations (polymorphisms). The polymorphisms found in Europe mainly consist of two combinations of mutations, that is combinations of five single‐nucleotide polymorphisms (SNPs) of cyp51A, referred to as cyp51A‐5SNPs, and combinations of three SNPs of cyp51A, referred to as cyp51A‐3SNPs. Few studies have compared the distributions of cyp51A polymorphisms between different regions. Objectives: The aim of this study was to investigate the regional differences of cyp51A polymorphisms. Methods: We compared the proportions of cyp51A polymorphisms in clinical and environmental strains isolated in various countries, and analysed the strains phylogenetically using short tandem repeats (STRs) and whole‐genome sequence (WGS). Results: Among the Japanese strains, 15 out of 98 (15.3%) clinical strains and 8 out of 95 (8.4%) environmental strains had cyp51A polymorphisms. A mutation of cyp51AN248K was the most prevalent polymorphism in both clinical (n = 14, 14.3%) and environmental strains (n = 3, 3.2%). Only one environmental strain harboured cyp51A‐5SNPs, which was reported to be the most prevalent in Europe. For phylogenetic analyses using STRs and WGS, 183 and 134 strains, respectively, were employed. They showed that most of the strains with cyp51AN248K clustered in the clades different from those of the strains with cyp51A‐5SNPs and cyp51A‐3SNPs as well as from those with TR34/L98H mutations. Conclusions: This study suggests that there are genetic differences between cyp51A polymorphisms of A. fumigatus in Japan and Europe. [ABSTRACT FROM AUTHOR]

Multi-azole resistant Aspergillus fumigatus carrying TR 46 /Y121F/T289A was isolated from a patient in Japan in Dec 2013. This strain grouped into the same clade of the ones which were clinically isolated in France and Germany. A. fumigatus harboring this mutation could be rapidly diffused outside the Eurasian continent. [ABSTRACT FROM AUTHOR]

The prevalence of azole-resistant Aspergillus fumigatus (ARAF) in Japan is unclear. We aimed to investigate the epidemiology of clinically isolated Aspergillus species and the frequency of azole resistance in Aspergillus species, particularly Aspergillus fumigatus, in the Kyoto and Shiga regions of Japan. Strains of clinically isolated Aspergillus species were prospectively collected from nine acute care hospitals. Species identification was performed by DNA sequence analysis, and all strains were subjected to antifungal susceptibility testing. Sequencing of the Aspergillus cyp51A gene and promoter region and genotyping by short tandem repeats were performed for ARAF isolates. A total of 149 strains were collected, and 130 strains were included for the subsequent analysis after the exclusion of duplicate isolates. The most commonly isolated species was Aspergillus fumigatus, accounting for 43.1% (56 isolates) overall, and seven (12.7%) of 55 strains of A. fumigatus were azole-resistant. Azole-resistance of other Aspergillus species were also found that two (22.2%) of nine strains of A. tubingensis and two (28.6%) of seven strains of A. flavus were azole-resistant. DNA sequence analysis of the ARAF strains revealed that two carried the cyp51A TR34/L98H mutation, one carried G448S, one carried M220I, and three had no relevant mutations (wild type). Genotyping and phylogenetic analyses showed that the TR34/L98H strains were clustered with the strains from the Netherlands and France. These data suggest the emergence of ARAF with TR34/L98H in Japan, and continuous surveillance will be important to identify trends in resistance., (© The Author(s) 2019. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.)

Recently, azole-resistant Aspergillus fumigatus containing a 34-bp or 46-bp tandem repeat in the promoter region of cyp51A combined with amino acid substitution(s) has appeared in the environment worldwide, including several Asian countries. In this study, we isolated the 34-bp tandem repeat-containing azole-resistant A. fumigatus strain OKH50 from a patient in Japan in May 2016. The patient had not been treated with medical azoles before the strain isolation, suggesting that the resistant property was acquired before infection. In addition, the patient had not traveled overseas. Our analysis of short tandem repeats of the strain indicates that the strain is strongly related to the 34-bp tandem repeat-containing isolates from European countries and Asia-Oceania countries but not to susceptible isolates from Japan, suggesting that the strain was introduced from overseas and might spread in Japan., (Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

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.

Azole antifungals are used not only clinically for fungal infections but also used as agricultural fungicides. Recently, azole-resistant Aspergillus fumigatus containing a tandem repeat in the promoter region of cyp51A combined with amino acid substitution(s) appears in the environment in Eurasia, especially in several European countries. Although azole fungicides have been used in Japan, especially in Hokkaido, surveillance and characterization of A. fumigatus in Hokkaido have not been reported. In this study, we collected soil samples from farms that used an azole fungicide in the Tokachi area of eastern Hokkaido, isolated 91 A. fumigatus strains, and determined the minimal inhibitory concentrations of medical azoles required for these strains. Moreover, because causative agent A. fumigatus is ubiquitous in the air and acquired from the environment, we collected 22 clinical isolates of A. fumigatus to measure their susceptibility to medical azoles in a hospital in the Tokachi area. Our data show that almost all A. fumigatus isolates retained susceptibility to medical azoles. Clinical isolates OKH34 and OKH6 showed 8 and 2 μg/mL of voriconazole, respectively, as the minimal inhibitory concentration. Both isolates did not contain tandem repeat in cyp51A promoter region. An isolate contained G448S mutation in cyp51A conferring voriconazole resistance, which is the first report from Japan. Our data shows the existence of azole-resistant and low azole-susceptible clinical isolates and highlight the necessity for continuous surveillance in Japan because resistant A. fumigatus strains can arise through clinical or environmental selection or could be introduced from overseas., (Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)