Dermatophytes are fungi capable of digesting keratin and able to infect the skin surface of animal. Among them, the anthropophilic species Trichophyton rubrum is the most important human pathogen in Japan as the cusetive species of tinea lesions. The lesions caused by this fungus are known to be mild in their inflammatory reaction. More than 20% of the Japanese population is believed to be suffering from tinea pedis and the situation have not changed despite the introduction of new potent antifungal drugs. Several attempts made to cultivate the fungus on the skin surface has revealed the presence of pathogenic dermatophytes in healthy looking skin around a lesion or on the skin of surrounding individuals. Also, more than half of tinea pedis patients are left untreated or are treated intermittently only when the patient has noticed uncomfortable symptoms due to a lesion. The low QOL impairment due to tinea pedis lesions by anthropophilic dermatophytes is one reason preventing complete cure and has resulted in a growing number of tinea pedis patients, especially among the aged. To achieve control of the infections by anthroppphilic dermatophytes, the ecological background of the causative fungi should be taken under consideration rather than their eradication.
2008年度日本医真菌学会賞を受賞した機会に研究を回顧した．黒色真菌に関する研究が多いのは偶然である．高度の微生物学的(菌学的)水準が重要な目標であった．その成果を学会で報告し，論文を発表した．投稿誌は研究中ないし執筆前から選択した．この姿勢は若き日の国立衛生試験所と米国CDC(Centers for Disease Control and Prevention)での経験で築かれた．論文が評価されると国際会議のシンポジウム，講演に招かれ自然に研究者のnetworkが構成された．他の臨床科，施設からの依頼に応じ時に期待以上の成果を挙げた．また講演と総説や成書の執筆依頼が次第に増加し，他の研究者の報告を含めて発表した．特に海外(および国内での国際会議)での講演は英語能力を鍛える機会として参加した．在籍したそれぞれの施設で優れた上司，先輩，同僚，後輩に恵まれた．
An isolate of Arthroderma simii was successfully mated with a tester strain of A. vanbreuseghemii cultured on the plate of simple agar with some hair on it at 27 °C. Confirmation of sexual reproduction was made by the detection of hybrids of two parental genotypes. The implications of this result are discussed from the viewpoint of a reevaluation of the species boundaries of dermatophytes.
Up to now, 30 mitochondrial DNA(mtDNA)and 4 rDNA types of Sporothrix schenckii strains have been identified. Here, seventy-six isolates of S. schenckii from Mexico, Guatemala, Brazil, Thailand and India were genotyped and studied epidemiologically by mtDNA restriction fragment length polymorphisms(RFLP)and internal transcribed spacer region(ITS)-RFLP analysis and two new mtDNA types, Type 31 and Type 32, were found. Type 30, previously reported by Mora-Cabrera et al. was confirmed to be Type 3 and designated as blank. Of 48 isolates from Mexico, 41 belonged to Group A wherein Type 2(13 isolates), Type 3(10)and Type 28(7)were dominant. All ten isolates from India and Thailand belonged to Group B. The 52 Group A and 24 Group B isolates corresponded to rDNA Type I and Type IV , respectively, reported by Watanabe et al.(Nippon Ishinkin Gakkai Zasshi 45: 165-175, 2004).