Genomic characterization of sexually transmitted Trichophyton mentagrophytes genotype VII causing genital dermatophytosis in Italy.

Dermatophytes are among the most common causes of superficial fungal infections worldwide. In recent years, an increasing number of cases of sexually transmitted dermatophytosis have been reported in Europe, mainly associated with Trichophyton mentagrophytes genotype VII. Genomic data on circulating strains remain limited, particularly in Southern Europe. In this study, we described three cases of sexually transmitted dermatophytosis caused by T. mentagrophytes genotype VII diagnosed in Italy and characterized using whole genome sequencing. Skin scale samples were collected from genital/perigenital lesions and processed for mycological culture, antifungal susceptibility testing, and genomic analysis. Internal transcribed spacer (ITS) region sequencing confirmed the identification of genotype VII in all isolates. Phylogenetic analysis based on ITS sequences and phylogenomic analysis based on core genome single nucleotide polymorphisms consistently showed that the three isolates clustered within the genotype VII lineage and were closely related to previously described European strains. Antifungal susceptibility testing revealed low Minimum Inhibitory Concentration (MIC) values for extended-spectrum triazoles (voriconazole and posaconazole) and amphotericin B. Genomic analysis demonstrated that all isolates carried the wild-type SQLE gene, with no mutations associated with terbinafine resistance. Sequence variations were observed in several members of the MEP protease gene family and in the ZafA transcription factor gene. These findings confirm the presence of sexually transmitted T. mentagrophytes genotype VII in Italy and support the hypothesis that this genotype is an emerging cause of dermatophytosis in Europe. The integration of genomic approaches with clinical and epidemiological data may improve the understanding of transmission dynamics and help identify potential outbreaks.