Molecular Epidemiology, Mating Types, Clinical, and Physiological traits of Microsporum canis in Humans and Companion Animals (Cats and Dogs) in the Guiyang Region, Southwest China

To date, the transmission patterns and epidemiological characteristics of the zoonotic dermatophyte Microsporum canis in southwestern Guizhou, China, remain poorly understood. This study employed a multiphase approach integrating retrospective analysis of seven years of dermatophytosis data with a prospective cross-sectional survey of skin infections in cats and dogs conducted from February 2024 to August 2024. A total of 51 M. canis isolates-34 derived from humans and 17 from cats and dogs-were systematically analyzed to assess genotypic, phenotypic, physiological, and MAT gene distribution profiles. Sequencing of the ITS, tubb, and rpb2 loci revealed high genetic homogeneity across all isolates. With the exception of the human-derived strain JYP 21030b, in which amplification at the MAT locus failed, all isolates were identified as MAT1-1 genotype. Clinically, infections in both humans and animals were predominantly localized to the scalp. Physiological assessments revealed that animal-origin strains exhibited enhanced thermotolerance and more robust urease production compared to human-origin strains. Notably, evidence of distant hybridization between M. canis (JYP 21030b) and T. mentagrophytes var. interdigitale (JYP 21030a) was observed, accompanied by dynamic changes and diversity in mating type genes, which may correlate with distinct clinical and physiological traits. In conclusion, M. canis remains the predominant zoonotic dermatophyte responsible for dermatophytosis in humans and companion animals in this region. Despite limited molecular divergence, differences in enzymatic activity and thermal growth profiles suggest functionally driven phenotypic adaptability, with animal-origin strains demonstrating heightened environmental resilience and potential for host switching. Furthermore, the occurrence of interspecies hybridization offers a novel explanation for the paradox of low genetic variation coupled with observable phenotypic heterogeneity, thereby providing new insights into the transmission dynamics, ecological adaptation, and public health implications of M. canis.

Authors: H. Hu, B. Jiao, Y. Deng, W. Luo, J. Zhou, W. Lei, Z. Shang, Y. Jiang, Z. Wang and Z. Zeng Title: Molecular Epidemiology, Mating Types, Clinical, and Physiological traits of Microsporum canis in Humans and Companion Animals (Cats and Dogs) in the Guiyang Region, Southwest China Full source: Mycopathologia, 2026,Vol 191, Iss 1, pp 24
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Abstract	Source
To date, the transmission patterns and epidemiological characteristics of the zoonotic dermatophyte Microsporum canis in southwestern Guizhou, China, remain poorly understood. This study employed a multiphase approach integrating retrospective analysis of seven years of dermatophytosis data with a prospective cross-sectional survey of skin infections in cats and dogs conducted from February 2024 to August 2024. A total of 51 M. canis isolates-34 derived from humans and 17 from cats and dogs-were systematically analyzed to assess genotypic, phenotypic, physiological, and MAT gene distribution profiles. Sequencing of the ITS, tubb, and rpb2 loci revealed high genetic homogeneity across all isolates. With the exception of the human-derived strain JYP 21030b, in which amplification at the MAT locus failed, all isolates were identified as MAT1-1 genotype. Clinically, infections in both humans and animals were predominantly localized to the scalp. Physiological assessments revealed that animal-origin strains exhibited enhanced thermotolerance and more robust urease production compared to human-origin strains. Notably, evidence of distant hybridization between M. canis (JYP 21030b) and T. mentagrophytes var. interdigitale (JYP 21030a) was observed, accompanied by dynamic changes and diversity in mating type genes, which may correlate with distinct clinical and physiological traits. In conclusion, M. canis remains the predominant zoonotic dermatophyte responsible for dermatophytosis in humans and companion animals in this region. Despite limited molecular divergence, differences in enzymatic activity and thermal growth profiles suggest functionally driven phenotypic adaptability, with animal-origin strains demonstrating heightened environmental resilience and potential for host switching. Furthermore, the occurrence of interspecies hybridization offers a novel explanation for the paradox of low genetic variation coupled with observable phenotypic heterogeneity, thereby providing new insights into the transmission dynamics, ecological adaptation, and public health implications of M. canis.