Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
Protist. 2013 Jul;164(4):497-509. doi: 10.1016/j.protis.2013.05.003. Epub 2013 Jun 14.
Blastocystis is a common unicellular anaerobic eukaryote that inhabits the large intestine of many animals worldwide, including humans. The finding of Blastocystis in faeces in mammals and birds has led to proposals of zoonotic potential and that these hosts may be the source of many human infections. Blastocystis is, however, a genetically diverse complex of many distinct organisms (termed subtypes; STs), and sampling to date has been limited, both geographically and in the range of hosts studied. In order to expand our understanding of host specificity of Blastocystis STs, 557 samples were examined from various non-primate animal hosts and from a variety of different countries in Africa, Asia and Europe. STs were identified using 'barcoding' of the small subunit rRNA gene using DNA extracted either from culture or directly from faeces. The host and geographic range of several STs has thereby been greatly expanded and the evidence suggests that livestock is not a major contributor to human infection. Two new STs were detected among the barcode sequences obtained; for these, and for three others where the data were incomplete, the corresponding genes were fully sequenced and phylogenetic analysis was undertaken.
芽囊原虫是一种常见的单细胞厌氧真核生物，栖息在世界上许多动物的大肠中，包括人类。在哺乳动物和鸟类的粪便中发现芽囊原虫，导致了其具有人畜共患潜力的提议，这些宿主可能是许多人类感染的来源。然而，芽囊原虫是一个由许多不同生物体（称为亚型；STs）组成的遗传多样性复杂体，迄今为止的采样无论是在地理范围还是在研究宿主的范围上都非常有限。为了扩大我们对芽囊原虫 STs 宿主特异性的理解，从非洲、亚洲和欧洲的各种非灵长类动物宿主和不同国家中检查了 557 个样本。使用从小亚基 rRNA 基因提取的 DNA 进行 DNA 提取，使用“条形码”技术对 STs 进行了鉴定，该基因要么来自培养物，要么直接来自粪便。因此，几个 STs 的宿主和地理范围得到了极大的扩展，有证据表明，家畜不是人类感染的主要来源。在获得的条形码序列中检测到了两个新的 STs；对于这些 STs 以及其他三个数据不完整的 STs，对相应的基因进行了完整测序，并进行了系统发育分析。
