Gross and microscopic findings of dermatophytes cultured on potato dextross agar

Park, Yong Myo; Choi, Jong Soo; Kim, Ki Hong

Abstract

To ease the convinience of indentification of common dermatophytes in Korea and to check the possibility of diseovering new species not yet reported in Korea, several species of dermatophytes were cultured on potato dextrose agar(PDA) at the room temperature. They were 46 strains isolated from Korea and 6 domestic strains from a foreign country. Gross and microscopic findings of their colonies were examined. The colonial morphology and microscopic appearance were compared with those of the same strains on Sabouraud dextrose agar(SDA) and corn meal agar(CMA). The results were as follows Typical T. rubrum and its varisnts showed characteristic wine red pigmentation which was rapid, diffuse and uniform, typically arrsnged microconidia were better on PDA. T. mentagrophytes showed yellow-brown pigmentation which were more rapid and darker in the center with gradual fading to the periphery. The mscroconidia, grape-like clusters of microconidia and spiral hyphae were seen better on SDA. T. tonsurans showed characteristic mahogsny colored pigmentation, ballooned microconidia and macroconidia which were seen better on PDA, but diffusible pigmentation of agar were present on SDA only. The gross morphology of T. verracosum were similar on PDA and SDA, but macroconidia were seen better on PDA and CMA, and tortuous hyphae with antler-like branching were seen better on SDA. T. rnegninii showed green-brown pigmentation which appeared rapidty and prominently on PDA. T. rubrum-like microconidia were seen better on PDA and CMA, but in SDA only hyphae were seen. The gross morpholgy of M. canis was similar on PDA and SDA, but spindle shaped macroconidia were seen more typically on PDA. The gross morphology and microscopic appearance of M. gypseum were very similar in all three media. M. ferruginenm showed characteristic rust colored pigmentation and bamboo hyphae which were seen more typically on PDA. The gross morphalogy of E floceosum were similar on PDA and SDA, but cluster formation of club shaped macroconidia were seen more prominently on PDA and CMA. These findings suggest that PDA is a mare convincing media t6Cifferentiate among dermatophytes belonging to genus Trichopkyton.