Minipreparation of total cellular DNA is useful as an alternative molecular marker of mitochondrial DNA for the identification of Trichophyton mentagrophytes and T. rubrum.

Total cellular DNA was extracted from 18 isolates of Trichophyton mentagrophytes and six isolates of unidentified Trichophyton species taken from tinea corporis, tinea cruris and tinea pedis patients by a minipreparation method. The DNA was digested with the restriction enzymes HaeIII and MspI, followed by electrophoresis on agarose gels. The restriction enzyme profiles of the DNAs were compared with those of mitochondrial (mt) DNA extracted from reference strains of T. mentagrophytes (Arthroderma simii, A. benhamiae and A. vanbreuseghemii) and T. rubrum. All 18 T. mentagrophytes isolates showed the same DNA profiles as mtDNA from A. vanbreuseghemii. The six unidentified Trichophyton isolates exhibited DNA profiles the same as that of mtDNA from T. rubrum. Consequently, these isolates were identified as T. rubrum. In conclusion, restriction enzyme analysis of total cellular DNA prepared by the minipreparation method is considered to be useful as an alternative method of mtDNA analysis and is helpful for the identification of these dermatophyte species.