鬚癬毛癬菌複合種之研究

Abstract

鬚癬毛癬菌複合種屬於皮癬菌，為重要的致病真菌，在臨床上可造成各樣的皮膚感染，如頭癬、臉癬、體癬、手癬、足癬、甲癬等。其宿主範圍極廣，可寄生於人類、貓、狗、鼠、刺蝟身上，利用人類及動物身上的角質物質為營養來源。傳染途徑為人與人、及人與動物直接或間接的接觸造成感染，為公共衛生上一個重要的問題。因此，正確的真菌培養及檢定，有助於了解感染的來源，並加以阻斷，使病人得到完全的治療。 鬚癬毛癬菌複合種傳統上包括三個主要的種：鬚癬毛癬菌、趾間毛癬菌、及刺蝟毛癬菌。由於三者在形態學上相似，且存在著許多的中間型及變異型，而使此一複合種成員的命名產生相當大的混淆，同時使三者的分類地位無法完全釐清。這不僅造成在研究時我們可能會選到錯誤的菌株，也使得菌種統計數據變得不可靠，阻礙了對此菌的研究。 本實驗利用台灣本土人類及動物分離出的48株鬚癬毛癬菌複合種菌株，進行研究。除了分析臨床表現與菌種形態的關係外，我們並根據Gräser等人最新的分類方法，使用ITS1-5.8S-ITS2區段及β-tubulin基因及進行分類分析。結果發現，依最新的分類方法，48株鬚癬毛癬菌複合種中，21株屬於趾間毛癬菌人類株分群，22株屬於趾間毛癬菌動物株分群，5株為刺蝟毛癬菌，沒有鬚癬毛癬菌。由於這種分類方法與我們傳統使用的習慣不同，會造成檢定上的混淆，因此我們認為此分類方法的適用性仍待進一步的評估。

Trichophyton mentagrophytes complex, belonging to dermatophytes, is a group of important pathogenic fungi that can cause various human skin infections such as tinea capitis, tinea faciei, tinea corporis, tinea manuum, tinea pedis and onychomycosis. They have a wide range of hosts, including human, cats, dogs, rats, and hedgehogs and can use the keratinous substracts from the hosts as the nutrition source. This is an important public health issue because they can transmit between humans and between human and animals by direct or indirect contact. Culturing and accurate identification of these fungi can help to clarify the routes of infection. This is also very important in the treatment of patients. Traditionally, T. mentagrophytes complex consists of three main species, viz. T. mentagrophytes, T. interdigitale and T. erinacei. Due to morphological similarity and existing intermediate forms and variants, there is a great confusion in their taxonomic status. This confusion leads to trouble in choosing correct strains for research and the epidemiological statistics of fungal infections by this group of fungi and further impeding our communicating about it. In this study, we used 48 isolates of the T. mentagrophytes complex obtained from human and animals in Taiwan to perform clinical analysis and molecular taxonomy. We examined the correlation between morphology of the isolates and the clinical presentations. We also used ITS1-5.8S-ITS2 andβ-tubulin gene regions for molecular taxonomy according to the latest taxonomic definition of the T. mentagrophytes complex proposed by Gräser et. al. By this definition, our result shows that among 48 isolates, 21 isolates belong to the anthropophilic strain of T. interdigitale; 22 isolates belong to the zoophilic strain of T. interdigitale; and 5 isolates belong to T. erinacei. No T. mentagrophytes was found. Because the new classification is quite different from what it used to be, confusion in the nomenclature of the T. mentagrophytes complex will be expected. The applicability of Gräser’s taxonomic concept requires further evaluation.