Historic topics on classification of Trichophyton mentagrophytes complex

D. Gruby (1842-1844) detected the fungus in tinea as a causative agent and C.P. Robin (1853) described Microsporum mentagrophytes that was transferred to Trichophyton by Blanchard (1896). Sabouraud (1910) established a group of ectothrix microïde which was divided into gypseum type (6 species: T. asteroids, T. granulosum, T. lacticolor and 3 species) and niveum type (T. radians and T. denticulatum). Thereafter, Epidermophyton simii Pinoy, 1912 and T. interdigitale Priestly, 1917 were reported. These species were classified as T. mentagrophytes by C.W. Emmons (1934 and 1940). Arthroderma simii Stockdale et al., 1965, A. benhamiae, Ajello and Cheng, 1967 and A. vanbreuseghemii Takashio, 1973 were discovered as teleomorphs of T. simii, T. mentagrophytes var. granulosum and T. mentagrophytes (mainly granulosum-asteroides form), respectively. Makimura et al., (1998) reported phylogenetic classification of T. mentagrophytes complex strains based on DNA sequences of nuclear ribosomal internal transcribed spacer 1 (ITS1) regions, indicating that A. vanbreuseghemii and T. interdigitale belong to the same clade that was later named T. interdigatale by Gräser et al.(1999). This naming has confused medical and veterinary doctors since anthropophilic isolates (T. interdigitale) and zoophilic isolates (A. vanbreuseghemii) were included as the same species.