Klinger M, Theiler M, Bosshard P P
Department of Dermatology, University Hospital Zurich, Zurich, Switzerland.
Faculty of Medicine, University of Zurich, Zurich, Switzerland.
J Eur Acad Dermatol Venereol. 2021 Apr;35(4):1017-1025. doi: 10.1111/jdv.17106. Epub 2021 Feb 3.
Trichophyton mentagrophytes (formerly Arthroderma vanbreuseghemii) and its clonal offshoot Trichophyton interdigitale, which are leading causes of dermatophytoses, have recently been recognized as two separate species. Over the last 20 years, several internal transcribed spacer (ITS) genotypes of Trichophyton mentagrophytes and Trichophyton interdigitale have been identified, some of which have specific characteristics and lead to typical clinical manifestations.
The aim of this study was to determine the current epidemiology of Trichophyton mentagrophytes and Trichophyton interdigitale genotypes in Switzerland, particularly in the Zurich area.
Consecutive cases diagnosed by ITS sequencing between 2009 and 2019 were retrospectively analysed.
A total of 81 Trichophyton mentagrophytes and 81 Trichophyton interdigitale cases were investigated. T. mentagrophytes infections clearly differed from T. interdigitale infections by affecting younger and more frequently female patients, targeting almost exclusively head and body rather than feet and toenails, leading to inflammatory dermatophytosis and often requiring a combination of systemic and topical treatment. Seven different T. mentagrophytes genotypes (II*, III, III*, IV, VII, VIII and XXVI) were observed, with genotype XXVI being discovered in this study. Genotype III occurred most frequently (56% of all T. mentagrophytes cases) and affected predominantly children. Genotypes III* and VII led to inflammatory tinea in most cases. Four strains that proved to be terbinafine resistant belonged to the 'Indian genotype' VIII, which mostly caused tinea glutealis and inguinalis.
Being able to distinguish between Trichophyton mentagrophytes and Trichophyton interdigitale is of paramount importance as the two species cause different clinical presentations. In addition, ITS genotyping allows recognizing sources of infection and potential terbinafine resistance. The latter needs to be confirmed by resistance testing or by sequencing part of the squalene epoxidase (SQLE) gene.
须癣毛癣菌（原称范布列希米节皮菌）及其克隆分支指间毛癣菌是皮肤癣菌病的主要病因，最近被确认为两个独立的物种。在过去20年中，已鉴定出几种须癣毛癣菌和指间毛癣菌的内部转录间隔区（ITS）基因型，其中一些具有特定特征并导致典型的临床表现。
本研究的目的是确定瑞士，特别是苏黎世地区须癣毛癣菌和指间毛癣菌基因型的当前流行病学情况。
对2009年至2019年间通过ITS测序诊断的连续病例进行回顾性分析。
共调查了81例须癣毛癣菌病例和81例指间毛癣菌病例。须癣毛癣菌感染与指间毛癣菌感染明显不同，前者感染的患者更年轻，女性更为常见，几乎仅累及头部和身体而非足部和趾甲，导致炎症性皮肤癣菌病，通常需要全身和局部治疗联合应用。观察到七种不同的须癣毛癣菌基因型（II*、III、III*、IV、VII、VIII和XXVI），其中XXVI基因型是在本研究中发现的。基因型III出现频率最高（占所有须癣毛癣菌病例的56%），主要影响儿童。基因型III*和VII在大多数情况下导致炎症性癣。四株对特比萘芬耐药的菌株属于“印度基因型”VIII，主要引起股癣和腹股沟癣。
能够区分须癣毛癣菌和指间毛癣菌至关重要，因为这两个物种会导致不同的临床表现。此外，ITS基因分型有助于识别感染源和潜在的特比萘芬耐药性。后者需要通过耐药性测试或对角鲨烯环氧酶（SQLE）基因的部分进行测序来确认。
