Toenail onychomycosis caused by dermatophytes is a significant medical and financial worldwide burden. Relatively scant research has been undertaken as to the predominant species and strains causing this condition in Australia, which is a unique isolated continent with diverse geographical, climatic and population regions. Four regions were selected in Eastern Australia: Far North Queensland, Rural Victoria, Melbourne Metropolitan and Tasmania. From each of these areas, communal nail dust bags from podiatric physicians' work were collected and analysed. A total of 32 dust bags were collected: 10 from Far North Queensland, 8 from Melbourne Metropolitan, 8 from Rural Victoria and 6 from Tasmania. Dermatophyte test medium was used to isolate dermatophytes from the dust, and the colonies were subcultured to Potato Dextrose Agar. Of the bags collected, in total 69% were positive for dermatophytes: 40% from Far North Queensland, 75% from Melbourne Metropolitan, 88% from Rural Victoria and 83% from Tasmania. The internal transcribed spacer (ITS) region of ribosomal DNA was used to identify and compare isolates. A total of 148 dermatophyte strains were identified. The predominant species isolated was Trichophyton interdigitale (125 isolates), which was found in all four regions. This species was further subdivided into four ITS genotypes: the first two were present in all regions, but the third was found only in the Melbourne Metropolitan area and the fourth only in Tasmania. Only one strain of Trichophyton rubrum was found and only in Rural Victoria. Eighteen isolates of Arthroderma quadrifidum were cultured from Rural Victoria and Tasmania and were further classified into three ITS genotypes. Some isolates rarely reported in clinical material were identified as Paraphyton cookei, Arthroderma tuberculatum and Arthroderma crocatum. A potentially new species of Arthroderma was also found in Melbourne Metropolitan. These findings reveal a unique dermatophyte fingerprint in toenails for Eastern Australia.

Department of Botany Faculty of Science Charles University Prague Czech Republic

Laboratory of Fungal Genetics and Metabolism Institute of Microbiology of the Czech Academy of Sciences Prague Czech Republic

School of Biomedical Sciences Charles Sturt University Wagga Wagga NSW 2650 Australia

School of Life and Environmental Sciences Faculty of Science Marie Bashir Institute for Infectious Diseases and Biosecurity The University of Sydney Sydney NSW 2006 Australia

School of Science RMIT University PO Box 71 Bundoora VIC 3083 Australia

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