Aspergillus fumigatus is the major etiologic agent of aspergillosis. Recently, its related species, A. lentulus, A. viridinutans and A. udagawae have been also reported as causative agents of aspergillosis, and the numbers of cases are increasing. Their susceptibilities against antifungal drugs, especially azoles, are different from that of A. fumigatus. Therefore it is essential to identify their species correctly for the appropriate treatment. However, there has been no report to date as to the isolation of the related species from the environment in Japan. The purpose of this study is to make a comparison between clinical isolates and environmental ones of the related species on susceptibilities against antifungal drugs and genetic diversity. First, we tried to isolate the related species from the environment in Japan by the baited method using corn and found some isolates belonging to A. lentulus, A. viridinutans and A. udagawae. They were identified on morphology and phylogeny. Then we examined their antifungal susceptibilities using the Dry Plate (Eiken Chemicals, Japan) according to the CLSI M38-A2 method. Some isolates of A. lentulus and A. udagawae have resistance properties against VRCZ, and some of A. viridinutans also showed resistance against VRCZ and ITCZ. These resistances closely resembled those of clinical isolates in pattern, degree and frequency, therefore they are considered as inherent resistance. Additionally, clinical isolates of A. viridinutans and A. udagawae showed a tendency to form a limited group in each clade on the phylogenetic tree.
Full conference title:
- ISHAM 19th (2015)