Abstract
Auxarthron is a genus within the Onygenales encompassing keratinophilic species with typical ascomata (gymnothecia) consisting of anastomosing network of thick-walled hyphae and small globose or oblate ascospores. No association of this genus with clinically relevant cases of human or animal infection has been reported. This paper describes the isolation of an undescribed Auxarthron species as an agent of proven onychomycosis affecting almost all fingernails in a man with psoriasis. The causality of the isolated fungus was verified by repeated sampling and direct microscopy revealing irregular septate hyphae. Based on micro- and macromorphological features and unique sequence data (ITS region, benA and RPB2 gene), the isolated fungus is proposed as the new species A. ostraviense. The sibling species of A. ostraviense, A. umbrinum, was isolated from three patients with suspected onychomycosis and a detailed clinical history is provided for one of these patients. All four isolates were tested for susceptibility to selected antifungal agents. Terbinafine and clotrimazole appear to be effective in vitro. The morphological identification of Auxarthron spp. is non-trivial, time-consuming and requires cultivation media other than Sabouraud glucose agar which is routinely used in dermatomycology.
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Acknowledgments
This work was supported by the institutional resources of Ministry of Education, Youth and Sports of the Czech Republic for the support of science and research. Molecular genetics analyses were supported by project GAUK 607812. We would like to thank Dr Lynne Sigler for valuable comments and recommendations, Dr Josef Vaníček for providing patient data, Dr Miroslav Hyliš for assistance with scanning electron microscopy and Dr Dagmar Jechova, who carefully read the manuscript.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and the writing of the paper.
Notes
1. The EMBL accession numbers for the ITS, benA and RPB2 of the ex-type strains of Auxarthron ostraviense sp. nov. are HE974452, HE974417 and HE974411.
2. The MycoBank (http://www.mycobank.org) accession number for Auxarthron ostraviense sp. nov. is MB801211.