Abstract: 【Objective】 An experiment was carried out to isolate and identify the pathogenic fungi from the skin scrapings of beef cattle affected by dermatophytes in Ningxia, in order to provide reference for the diagnosis, prevention and control of dermatophytes in cattle population. 【Method】 The samples of scrapings and hairs were collected from beef cattle affected by dermatophytes in Ningxia. Each sample was placed on microslide containing a drop of 10% potassium hydroxide solution and covered with a cover slip, and observed under the light microscope. Each sample was inoculated onto the Sabouraud’s dextrose agar medium（SDA）to isolate and purify the fungi, and the fungal isolates were observed under the light microscope containing lactophenol cotton blue stain, the identification and classification of each isolate were performed preliminarily according to the morphological characteristics. The conidial suspension at a density of 1×10⁸ cfu/mL from the isolates was used to infect the healthy ICR mice’s skin to confirm whether the isolates do has pathogenicity or not and to screen pathogenic fungi. The suspected pathogenic fungi’s genome DNA were extracted, the ITS sequences of which were amplified and sequenced, and finally classified according to the homology comparision and phylogenetic analysis combined with the morphological characteristics. 【Result】  According to the microscopic examination, many fungal hyphae and chlamydospore were observed in chains in the samples, and a lot microcondia inside the hairs. Twenty-three fungi were isolated from the samples, and the isolates were classified into the genera like Trichophyton, Aspergillus, Lichtheimia, Alternaria, Fusarium, Epicoccum, Mucor. Two of Trichophyton NXGY1 and NXGY2 were confirmed to be pathogenic fungi according to the skin infection experiments in mice, and all the infected mice with clinical symptoms like itching, dandruff increasing, scabbing, unhairing. The ITS sequence lengths of NXGY1 and NXGY2 were 660 bp and 662 bp, and the homology compared with Trichophyton verrucosum was up to 99% according to the ITS sequences homology comparison. Phylogenetic analyses showed that NXGY1 and NXGY2 were also highly similar to T. verrucosum. 【Conclusion】 The results indicated that NXGY1, NXGY2 isolated in this research were Trichophyton verrucosum.

Key words: beef cattle, dermatophytes, ITS sequences, phylogenetic analysis, Trichophyton verrucosum