The rDNA spacer regions provide easily accessible, polymorphic genetic loci for both species and strain identification of dermatophyte fungi. Nucleotide substitutions and length polymorphisms in the internal transcribed spacers (ITS) can be indexed by sequencing or by PCR restriction endonuclease analysis, and provide a rapid and accurate means of identifying dermatophyte taxa. Multiple sets of tandem repeats that vary in copy number both within and between strains produce length heterogeneity in the nontranscribed spacer (NTS) region. Amplification of these repeats using specific PCR, or their detection by Southern hybridisation with a generic ribosomal DNA probe, provides a sensitive and discriminatory technique for strain identification in T. rubrum and other dermatophyte fungi.

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An epidemiological investigation on dermatophytoses in Japan for the year 1997 was carried out with the following results. The number of dermatomycoses patients visiting the fourteen cooperating institutes that year was 8, 284. New outpatients with this condition accounted for 13.3% of all new outpatients in these institutes. Dermatophytoses patients numbered 7, 314 and were composed of: tinea pedis 4, 901 (63.8%), tinea unguium 1, 592 (20.7%), tinea corporis 557 (7.2%), tinea cruris 395 (5.1%), tinea manuum 215 (2.8%), tinea capitis 12, kerion celsi 3, tinea barbae 1 and granuloma trichophyticum 1. Of these, 117 were children under 15 years of age. Species and incidences of the 2, 273 strains isolated from the patients with dermatophytoses were as follows: Trichophyton (T.) rubrum 1, 628 (71.6%), T. mentagrophytes 617 (27.2%), Epidermophyton floccosum 9 (0.4%), Microsporum (M.) canis 2, M. gypseum 2, T. glabrum 1, and 15 undetermined strains. Candidiasis was found in 714 individuals: intertrigo 302, erosio interdigitalis 108, erythema infantum 85, oral candidiasis 51, paronychia et onychia 51, genital candidiasis 50, onychomycosis 15 and other atypical forms of candidiasis 39. Patients with tinea versicolor numbered 242 and those with malassezia folliculitis 15. There were nine cases of deep dermal mycoses. The results of superficial dermatophytoses for the year 1997 differed from those of 1991-92 in the following points: tinea corporis and tinea cruris were lower in number, while tinea unguium had increased in ratio and number continuously. M. canis infection tended to decrease. In the age distribution of tinea, in every clinical form the peak of distribution curve gradually shifted to a more elderly age group.

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We report the case of a 68-year-old man with eruption on his left arm in the lesion where he wore his wrist watch. He was treated with topical steroid ointment at another clinic. He also suffered from tinea pedis. Examination of the scale and hair showed hyphal elements. Histopathological examination revealed granulomatous reaction around the hair follicles. We found no fungal elements in the tissue in spite of detecting serial sections of them. Trichophyton rubrum was cultured from tissue and scale, and the case was diagnosed as Trichophytia profunda acuta of the glabrous skin. Spontaneous remission was shown only by topical treatment for tinea pedis. A therapy of “wait and see” may be one choice.

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Paracoccidioidomycosis (PCM) is a deep mycosis caused by the thermo-dependent dimorphic fungus Paracoccidioides brasiliensis and is prevalent in Latin American countries. An increase in PCM has been reported in recent years and the disease is now recognized as one of the imported fungal infections in Japan. To date, more than 15 cases of PCM have been reported in our country, and five of them were diagnosed by clinical and histopathological findings without mycological study. We applied 2 nested polymerase chain reaction (PCR) amplification methods for detecting P. brasiliensis genes from paraffin-embedded tissue specimens. Successfully amplified were: a 473 base pairs fragment of gp43 gene of P. brasiliensis (located from 741st to 1, 213rd base), and a 418 base pairs fragment of 5.8S ribosomal RNA gene of P. brasilienisis which included internal transcribed spacers (ITS) 1 and 2 (located from 131st at ITS1 to 195th at ITS2) in paraffin-embedded murine tissues infected with P. brasiliensis yeast cells. The authenticity of the PCR products was confirmed by nucleotide sequence analysis. These results indicate that the two nested PCR methods may be useful for diagnosis of PCM.

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