Chua Kyra Y L, Halliday Catriona L, Mason Amber, Vogrin Sara, Knox James, Chen Sharon C-A
Department of Microbiology, Dorevitch Pathology, Heidelberg, Vic, Australia; Department of Infectious Diseases, University of Melbourne, the Peter Doherty Institute for Infection and Immunity, Melbourne, Vic, Australia; Department of Infectious Diseases and Immunology, Austin Health, Heidelberg, Vic, Australia.
Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, New South Wales Health Pathology, Westmead Hospital, Westmead, NSW, Australia.
Pathology. 2025 Oct;57(6):762-766. doi: 10.1016/j.pathol.2025.03.008. Epub 2025 May 18.
The aim of this study was to estimate the prevalence of Trichophyton indotineae, an emerging drug-resistant fungus, in specimens submitted for dermatophyte examination at a large laboratory in Melbourne, Australia, from January to June 2024, and to examine approaches for best laboratory practice for detection of this species. T. indotineae has not been previously isolated at our laboratory. We examined all skin and hair specimens (nail specimens were excluded) for dermatophyte presence by microscopy and culture; species identification was performed by routine phenotypic methods. Trichophyton interdigitale, Trichophyton mentagrophytes and Trichophyton isolates identified to genus level only, which were urease-negative or urease-indeterminate after 7 days, underwent internal transcribed spacer (ITS) region sequencing for definitive identification. A total of 202 Trichophyton isolates from 202 specimens (196 patients) were studied. The most common site of infection was the foot (tinea pedis, 39.3%) followed by, collectively, sites not specified (27.6%) and the groin (tinea cruris, 13.8%). Final identification revealed Trichophyton rubrum (n=128, 63.4%) as the most frequent species, followed by T. interdigitale (n=38, 18.8%) and T. indotineae (n=13, 6.4%). All T. indotineae isolates were initially phenotypically identified as T. interdigitale (n=7) or as Trichophyton species (n=6). T. indotineae caused tinea corporis (n=4, 30.8%), tinea cruris (n=3, 23.1%), tinea manuum (n=2, 15.4%), tinea pedis (n=1, 7.7%), tinea capitis (n=1, 7.7%) and tinea in an unspecified site (n=2, 15.4%). The estimated prevalence of T. indotineae was 0.6% [95% confidence interval (CI) 0.3-1.0]. T. indotineae cannot be identified using phenotypic methods, and identification requires ITS sequencing. Whilst apparently uncommon herein, further studies are warranted to more accurately determine the likelihood of encountering this important species in different populations.
本研究旨在评估2024年1月至6月在澳大利亚墨尔本一家大型实验室提交进行皮肤癣菌检查的标本中，新兴耐药真菌印多蒂毛癣菌（Trichophyton indotineae）的流行情况，并探讨检测该菌种的最佳实验室操作方法。此前我们实验室尚未分离出过印多蒂毛癣菌。我们通过显微镜检查和培养，对所有皮肤和毛发标本（不包括指甲标本）进行皮肤癣菌检测；通过常规表型方法进行菌种鉴定。指间毛癣菌（Trichophyton interdigitale）、须癣毛癣菌（Trichophyton mentagrophytes）以及仅鉴定到属水平的毛癣菌分离株（7天后脲酶呈阴性或脲酶结果不确定），进行内部转录间隔区（ITS）测序以进行最终鉴定。共研究了来自202个标本（196名患者）的202株毛癣菌分离株。最常见的感染部位是足部（足癣，39.3%），其次是未明确部位（27.6%）和腹股沟（股癣，13.8%）。最终鉴定显示，红色毛癣菌（Trichophyton rubrum，n = 128，63.4%）是最常见的菌种，其次是指间毛癣菌（n = 38，18.8%）和印多蒂毛癣菌（n = 13，6.4%）。所有印多蒂毛癣菌分离株最初在表型上均被鉴定为指间毛癣菌（n = 7）或毛癣菌属菌种（n = 6）。印多蒂毛癣菌引起体癣（n = 4，30.8%）、股癣（n = 3，23.1%）、手癣（n = 2，15.4%）、足癣（n = 1，7.7%）、头癣（n = 1，7.7%）以及未明确部位的癣（n = 2，15.4%）。印多蒂毛癣菌的估计流行率为0.6% [95%置信区间（CI）0.3 - 1.0]。无法使用表型方法鉴定印多蒂毛癣菌，鉴定需要进行ITS测序。虽然在此处显然不常见，但仍有必要进行进一步研究，以更准确地确定在不同人群中遇到这种重要菌种的可能性。
