Subtypes and Mycologic Characteristics of Trichophyton Genus Isolated in Taegu Korea

Kim, Ki Hong; Moon, Byung Chun; Choi, Jong Soo

Abstract

BACKGROUND: Dermatophytosis has been investigated by many dermatologist, who has Identified 9 species, specific in Korea among the 43 world-wide species. Two isolates of Trichophuyton (T.) genus common in Korea are Trichophyton (T.) rubrum and T. verrucosum bas been identified for the first time in Korea in 1986 and bas been increasing in unmber of reported cases. OBJECTIVE: In this study, we try to classify the subtype of T. rubrum, T. mentagrophytes and T. verrucosum, as well as to identifiy the invasion of new so far, unidentified species with similar morphology. METHOD: Forty strains of T. rubrum, 40 strains of T. mentagrophytes and 30 strains of T. verrucosum, isolated from dermatophutosis patients in Taegu area, ware examined for their characteristics, utilizing various media, hair perforation test and urease test.
RESULTS
T. rubrum was classified into 5 subtypes: granular type, portowine type, diffusable pigment producing type, yellow type and non-pigmented type, according to their color and surface morphology. Portowine type showed characteristic cottony surface with portowine color on the reverse side on gross morphology and microspcopically on rare occasion macroconidia and minimal tear-drop microconidia. Granular type showed granular surface with portowine color on the reverse side, and many pencil-shaped macroconidia and abundant microconidia microscopically. Diffusable pigment-producing type showed similar findings, except for melanoid diffusible pigment on the Sabouraud media. Yellow type showed a cottony surface and yellow color on the reverse side. Microscipically, findings were the same to portowine type. Noncolored type showed no coloring on the reverse side; otherwise same as those of portowine type. All strains were negative on hair perforation test. One of 40 strains of T. rubrum showed typical gross and microscopic findings of T. rubrum, positive urease test and negative hair perforation test. All these findings suggest T. raubischeckii. This strains was identified for the first time in Korea. T. mentagrophytes was classified into 4 subtypes: granular type, powdery type, purple-red type, and cottony type, according to their color and surface morphology. Granular type showed fawn brown color with coarse granular surface grossly, and many club-shaped macroconodia and grape shaped microconidia but rare spiral hyphae microscopically Powdery type showed cream to buff colored, fine powdery surface, each colony being surrounded by mild cottony border and many club-shaped macroconodia, grape shaped microconidia and spiral hyphae microscopically. Red-purple type showed characteristic red-purple color with cottony and powdery surFace, and microconidia and spiral hyphae microscopically. Cottony type showed abundant whitish cottony surface and many round microconidia microscopically. T. yerrucofum showed a very slowly growing, mountain-like appearance with shallow valley and narrow or wider skirt. Microspcopically, string-bean shaped macroconidia, a few microconidia, and many chlamydoconidia were present. All strains showed positive hair perforation. Nineteen of 30 strains showed negative urease test. All strains grew on Trichophyton media III. Twenty (65.4%) of 31 strains grew on Trichophyton media IV.
CONCLUSION
These findings suggest that all dermatophytes should be examined thoroughly to investigate any strain that may be brought in from foreign countries.