Infection of Trichophyton verrucosum in cattle breeders, Poland: A 40-year retrospective study on the genomic variability of strains.

Trichophyton verrucosum is a zoophilic fungus that is the most frequent aetiological agent of dermatophytosis in cattle. During the last few years, the number of cases of T. verrucosum from humans has been increasing constantly, which is correlated with the presence of cattle-rearing farms. We identified and analysed T. verrucosum strains isolated from humans and cattle. Identification was carried out traditionally by correlating both the clinical manifestations with a micro- and macroscopic examination. To confirm the species affiliation fully, molecular differentiation methods were used. Direct analysis revealed the presence of arthrospores. The macro- and micromorphology of the isolates obtained from material sampled was homogeneous, and characterised for T. verrucosum. The phylogenetic analysis based on the ITS sequences demonstrated that the strains formed a monophyletic group with T. verrucosum ATCC10 695 with a support of 99%. The MP-PCR analysis indicates high invariability of genomes of strains from humans and animals. MSP-fingerprinting analysis gives the same results as the MP-PCR analysis. To sum up, the rDNA ITS sequence analysis in combination with macro- and micro-morphology only facilitated T. verrucosum species identification without the possibility of intraspecific differentiation. Finding and testing methods, especially molecular technique, with sufficient discriminatory power, is the present challenge for mycologists.