Trichophyton concentricum
Trichophyton concentricum is an anthropophilic dermatophyte believed to be an etiological agent of a type of skin mycosis in humans, evidenced by scaly cutaneous patches on the body known as tinea imbricata. This fungus has been found mainly in the Pacific Islands and South America. Growth and morphology Trichophyton concentricum produce dense, slow-growing folded colonies which are mostly white to cream colored on Sabouraud's dextrose agar and their hyphae are normally branched, irregular and septate with antler tips resembling T.schoenleinii. The production of conidia is unusual, however when present, microconidia and macroconidia are smooth walled with a diameter of approximately 4 microns and 50 μm respectively. Due to its resemblance to macroconidia, hyphae are sometimes falsely identified as macroconidia. These fungi are also considered to be osmotolerant because of their ability to grown small colonies on 5% NaCl media and are. Hair perforation assays are generally negative with T. concentricum and growth is poor at 37 °C. While T. concentricum is considered to be independent of external vitamin sources, growth is more robust with thiamine supplementation. This characteristic feature is commonly used to distinguish between T. concentricum and T. schoeleinii. Overall, the natural habitat and growth of T. concentricum is