Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Department of Medical Parasitology and Mycology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
BMC Infect Dis. 2019 Sep 5;19(1):776. doi: 10.1186/s12879-019-4407-3.
Due to the similarity of Strongyloides stercoralis with free-living nematodes of Rhabditis species they might be miss-diagnosed with each other in microscopical examination of stool samples. The aim of this study was molecular characterization and differentiation of human derived isolates of S. stercoralis and Rhabditis species based on the mitochondrial gene of cytochrome c oxidase subunit 1 (cox1) amplification.
Using parasitological methods, ten isolates of S. stercoralis and three isolates of Rhabditis spp. were obtained from fresh stool samples of patients and the genomic DNA of the samples were extracted. PCR amplification of cox1 gene was carried out for all the isolates and the products were sequenced.
The phylogenetic analysis illustrated that S. stercoralis and Rhabditis spp. isolates were placed in two distinguishable separate clades. Inter-species genetic variation between isolates of S. stercoralis and Rhabditis spp. were ranged from 13.5 to 14.5%.
Cox1 gene was a suitable marker for discrimination of S. stercoralis from Rhabditis spp. retrieved from human in the current study. The availability of gene sequence information will be helpful in the future development and validation of discriminatory PCR-based assays of these nematodes.
由于粪样镜检中，粪类圆线虫与自由生活的小杆线虫属 Rhabditis 种之间具有相似性，因此它们可能会被误诊。本研究旨在基于细胞色素 c 氧化酶亚基 1（cox1）扩增的线粒体基因，对源自人类的粪类圆线虫和小杆线虫属分离株进行分子特征描述和区分。
采用寄生虫学方法，从患者新鲜粪便样本中获得了 10 株粪类圆线虫和 3 株小杆线虫属分离株，并提取了样本的基因组 DNA。对所有分离株进行 cox1 基因的 PCR 扩增，对产物进行测序。
系统发育分析表明，粪类圆线虫和小杆线虫属分离株分别位于两个可区分的独立分支上。粪类圆线虫和小杆线虫属分离株之间的种间遗传变异为 13.5%至 14.5%。
cox1 基因是区分本研究中源自人类的粪类圆线虫和小杆线虫属的合适标记。该基因序列信息的可用性将有助于未来开发和验证这些线虫的基于 PCR 的鉴别检测方法。
