Diagnosis of dermatophytosis is relatively easy with the typical clinical feature but sometimes we need more studies such as.direct microscopy and culture to.confirm the disease. The direct microscopic_ test is simple and rapid, but the result , is often complexing, and the culture needs much experience, skill, and deep knowledge in mycology.
In 1969, Taplin et al. devised Dermatophyte Test Medium(DTM) which contains phenol red as a color indicator for the simplified diagnosis of dermatophytosis. Result can be evaluated by noting the change of the color indicator of the medium from yellow to red without detailed knowledge of colony morphology. So the non-mycologist can recognize well by color change of the medium.
Moreover DTM is superior to Sabouraud medium in. eliminating bacterial contamination, allowing a higher recovery rate and early recongnizing, since the color change of the medium begin to appear with the growth of fungus.
The cultures were done on DTM and Sabouraud medium in 105 cases of the suspected dermatophytosis. In DTM, dermatophytes were cultured in 53 cases(M. ca.nis 1, T. mentagrophytes 24, T. rubrum 28) and the color changes were observed in all of them. The others were 29 cases of Candida spp., 5 cases of saprophytes, and only one case of bacterial contamination was observed. Compared with DTM, the dermatophytes were cultured in 36 cases and bacterial contamination were 16 cases in Sabouraud medium.
The colors of DTM of 53 cases of dermatophytes were changed to red between the second to fourteenth day after culture. In 3 cases of Candida spp. among 29, 3 case of saprophytes among 5, the color change of DTM begin to appear after tenth day of culture.
So DTM is very Lseful for the diagnosis of dermatophytosis by unskilled personnel under most environmental condition with only rudimentary $nowledges of colonial morphology to distinguish contaminant fungi and bacteria from dermatophytes.
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