Nitte (deemed to be University), Nitte University Centre for Science Education and Research, Mangaluru, Karnataka, India.
Nitte (deemed to be University), KS. Hedge Medical Academy, Mangaluru, Karnataka, India.
PLoS One. 2024 Jul 9;19(7):e0306829. doi: 10.1371/journal.pone.0306829. eCollection 2024.
An unambiguous identification of dermatophytes causing dermatophytoses is necessary for accurate clinical diagnosis and epidemiological implications. In the current taxonomy of the Arthrodermataceae, the etiological agents of dermatophytoses consist of seven genera and members of the genera Trichophyton are the most prevalent etiological agents at present. The genera Trichophyton consists of 16 species that are grouped as clades, but the species borderlines are not clearly delimited. The aim of the present study was to determine the discriminative power of subtilisin gene variants (SUB1-SUB12) in family Arthrodermataceae, particularly in Trichophyton. Partial and complete reads from 288 subtilisin gene sequences of 12 species were retrieved and a stringent filtering following two different approaches for analysis (probability of correct identification (PCI) and gene gap analysis) conducted to determine the uniqueness of the subtilisin gene subtypes. SUB1 with mean PCI value of 60% was the most suitable subtilisin subtype for specific detection of T.rubrum complex, however this subtype is not reported in members of T. mentagrophytes complex which is one of the most prevalent etiological agent at present. Hence, SUB7 with 40% PCI value was selected for testing its discriminative power in Trichophyton species. SUB7 specific PCR based detection of dermatophytes was tested for sensitivity and specificity. Sequences of SUB7 from 42 isolates and comparison with the ITS region showed that differences within the subtilisin gene can further be used to differentiate members of the T. mentagrophytes complex. Further, subtilisin cannot be used for the differentiation of T. benhamiae complex since all SUB subtypes show low PCI scores. Studies on the efficiency and limitations of the subtilisin gene as a diagnostic tool are currently limited. Our study provides information that will guide researchers in considering this gene for identifying dermatophytes causing dermatophytoses in human and animals.
明确鉴定引起皮肤癣菌病的皮肤癣菌对于准确的临床诊断和流行病学意义非常重要。在当前的节肢菌科分类中，皮肤癣菌病的病原体包括七个属，而目前 Trichophyton 属成员是最常见的病原体。Trichophyton 属包含 16 个种，这些种分为不同的分支，但种的边界并不明确。本研究旨在确定亚枯草菌素基因变体（SUB1-SUB12）在节肢菌科，特别是 Trichophyton 中的鉴别能力。从 12 个种的 288 个亚枯草菌素基因序列的部分和完整读取中，通过两种不同的分析方法（正确识别概率（PCI）和基因间隙分析）进行严格筛选，以确定亚枯草菌素基因亚型的独特性。平均 PCI 值为 60%的 SUB1 是最适合检测 T.rubrum 复合体的亚枯草菌素亚型，但该亚型在目前最常见的病原体之一 T. mentagrophytes 复合体成员中并未报道。因此，选择 PCI 值为 40%的 SUB7 来测试其在 Trichophyton 种中的鉴别能力。基于 SUB7 的 PCR 检测皮肤癣菌的敏感性和特异性进行了测试。从 42 个分离株中获得 SUB7 的序列，并与 ITS 区进行比较，结果表明亚枯草菌素基因内的差异可进一步用于区分 T. mentagrophytes 复合体的成员。此外，由于所有 SUB 亚型的 PCI 评分均较低，因此亚枯草菌素不能用于区分 T. benhamiae 复合体。目前，关于亚枯草菌素基因作为诊断工具的效率和局限性的研究有限。我们的研究提供了信息，将指导研究人员考虑将该基因用于鉴定引起人类和动物皮肤癣菌病的皮肤癣菌。
