Parasitology Department, Centre for Infectious Diseases and Microbiology Laboratory Services (CIDMLS), Institute of Clinical Pathology and Medical Research (ICPMR), Westmead Hospital, Westmead, Sydney, NSW, Australia; Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Faculty of Medicine and Health, Sydney Medical School, Westmead Clinical School, Marie Bashir Institute for Emerging Infectious Diseases and Biosecurity, Westmead Hospital (Research and Education Network), The University of Sydney, Sydney, NSW, Australia; Westmead Institute for Medical Research, Westmead, Sydney, NSW, Australia; Directorate General of Health Services (DGHS), Ministry of Health and Family Welfare (MOHFW), Dhaka, Bangladesh.
Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Faculty of Medicine and Health, Sydney Medical School, Westmead Clinical School, Marie Bashir Institute for Emerging Infectious Diseases and Biosecurity, Westmead Hospital (Research and Education Network), The University of Sydney, Sydney, NSW, Australia; Westmead Institute for Medical Research, Westmead, Sydney, NSW, Australia.
Int J Parasitol. 2019 Jun;49(7):555-567. doi: 10.1016/j.ijpara.2019.02.010. Epub 2019 May 18.
In the Indian subcontinent, infection with Leishmania donovani can cause fatal visceral leishmaniasis. Genetic variation in L. donovani is believed to occur rapidly from environmental changes and through selective drug pressures, thereby allowing continued disease occurrence in this region. All previous molecular markers that are commonly in use multilocus microsatellite typing and multilocus sequence typing, were monomorphic in L. donovani originating from the Indian subcontinent (with only a few exceptions) and hence are not suitable for this region. An multilocus sequence typing scheme consisting of a new set of seven housekeeping genes was developed in this study, based on recent findings from whole genome sequencing data. This new scheme was used to assess the genetic diversity amongst 22 autochthonous L. donovani isolates from Bangladesh. Nineteen additional isolates of the L. donovani complex (including sequences of L. donovani reference strain BPK282A1) from other countries were included for comparison. By using restriction fragment length polymorphism of the internal transcribed spacer 1 region (ITS1-RFLP) and ITS1 sequencing, all Bangladeshi isolates were confirmed to be L. donovani. Population genetic analyses of 41 isolates using the seven new MLST loci clearly separated L. donovani from Leishmania infantum. With this multilocus sequence typing scheme, seven genotypes were identified amongst Bangladeshi L. donovani isolates, and these isolates were found to be phylogenetically different compared with those from India, Nepal, Iraq and Africa. This novel multilocus sequence typing approach can detect intra- and inter-species variations within the L. donovani complex, but most importantly these molecular markers can be applied to resolve the phylogenetically very homogeneous L. donovani strains from the Indian subcontinent. Four of these markers were found suitable to differentiate strains originating from Bangladesh, with marker A2P being the most discriminative one.
在印度次大陆,感染利什曼原虫会导致致命的内脏利什曼病。据信,利什曼原虫的遗传变异是由于环境变化和选择性药物压力而迅速发生的,从而使该地区继续发生疾病。所有以前常用的分子标记,如多位点微卫星分型和多位点序列分型,在来自印度次大陆的利什曼原虫中都是单态的(只有少数例外),因此不适合该地区。本研究基于全基因组测序数据的最新发现,开发了一种由一组新的 7 个管家基因组成的多位点序列分型方案。该新方案用于评估 22 株孟加拉国本土利什曼原虫分离株的遗传多样性。还包括来自其他国家的利什曼原虫复合体(包括 L. donovani 参考株 BPK282A1 的序列)的 19 个额外分离株进行比较。通过使用内部转录间隔区 1 区(ITS1)的限制性片段长度多态性(ITS1-RFLP)和 ITS1 测序,所有孟加拉国分离株均被确认为利什曼原虫。使用 7 个新 MLST 基因座对 41 个分离株进行群体遗传分析,明确将利什曼原虫与利什曼原虫属区分开来。使用这种多位点序列分型方案,在孟加拉国利什曼原虫分离株中鉴定出 7 种基因型,与来自印度、尼泊尔、伊拉克和非洲的分离株相比,这些分离株在系统发育上存在差异。这种新的多位点序列分型方法可以检测利什曼原虫复合体中的种内和种间变异,但最重要的是,这些分子标记可用于解决印度次大陆遗传上非常同源的利什曼原虫菌株问题。其中 4 个标记被发现适合区分来自孟加拉国的菌株,其中标记 A2P 最具鉴别力。