P340 Detection of emerging genotypes in Trichophyton mentagrophytes complex: a proposal for handling biodiversity in dermatophytes

POSTER SESSION 3, SEPTEMBER 23, 2022, 12:30 PM - 1:30 PM: OBJECTIVE: The resistant and hypervirulent dermatophytes, which were found in India, have been described as a taxonomic novelty. It is urgent to detect the dermatophytes and their closely related clinical species fast and efficiently. Therefore, we evaluate the efficacy of diagnostic methods for the rapid detection of closely related clinical species. METHODS: Members of the Trichophyton mentagrophytes species complex were analyzed using Realtime-PCR, Dermagenius, LAMP, and MALDI-TOF in comparison with ITS sequencing. RESULTS: Dermagenius correctly recognized genotypes IV, VII, and IX as belonging to Trichophyton mentagrophytes, and all strains of T. interdigitale. However, genotype III and III* of T. mentagrophytes were recognized as T. interdigitale. The real-time PCR cannot distinguish these genotypes. In LAMP assay, T. indotineae, T. mentagrophytes III*, III, and IV, and T. interdigitale were positive. Trichophyton mentagrophytes genotype VII, and one strain of T. mentagrophytes genotype IX. In MALDI-TOF tree, the most of T. indotineae strains can be clustered in one clade. The rest of the genotypes are irregular. CONCLUSION: Dermagenius, real-time PCR, and LAMP cannot adequately distinguish among T. indotianeae, T. interdigitale, and T. mentagrophytes. Only T. indotineae from the Indian outbreak was approximately distinguishable with MALDI-TOF other than sequencing. We recommend to distinguish species only when they show an appreciable degree of adaptation and thus are clinically significant. Distinction of remaining clonal diversity is an epidemiological query and can be solved by haplotype numbering.