Molecular Epidemiology and Clinical Aspects of Dermatophytosis in Guiyang, Southwest China (2017-2023): A Single-Institution Retrospective Study

Epidemiological studies combining taxonomic and clinical data have been limited globally, particularly Guiyang, the most under-developed economic provincial capital city in southwestern China. A retrospective analysis was performed of dermatophyte epidemiology involving all culture-positive cases received between May 2017 and May 2023 at the Affiliated Hospital of Guizhou Medical University. Phylogenetic analysis was conducted on 391 dermatophyte isolates collected from patients using the rDNA internal transcribed spacer sequences. Clinical relevance information was analyzed statistically using T-test, one-way ANOVA, Kruskal-Wallis H test, and Chi-square test. Eight species were recognized, and their identity was confirmed on the basis of phylogenetics. Trichophyton rubrum (n = 308, 78.77%) ranked first, followed by T. mentagrophytes (n = 39, 9.97%) and Microsporum canis (n = 32, 8.18%). Tinea unguium (48.56%) was the most common type of dermatophytosis in this study, rates of detection being impacted by the host population's attention for dermatophyte infections. The hypothesized patterns of evolution in the M. canis series, T. mentagrophytes series and T. rubrum series, i.e. from zoophilic to a preponderantly anthropophilic nature, was reflected in clinical parameters such as host age, occupational background, infection pattern, degree of skin involvement and site preference. To the best of our knowledge, we provide the first detailed analysis of epidemiological characteristics and pathogenic patterns of dermatophytosis in Guiyang.