Stark D, van Hal S, Barratt J, Ellis J, Marriott D, Harkness J
University of Technology Sydney, Department of Medical and Molecular Biosciences, Broadway, Australia.
St Vincents Hospital, Department of Microbiology, Sydney, Australia.
J Med Microbiol. 2009 Mar;58(Pt 3):355-357. doi: 10.1099/jmm.0.006445-0.
Microsporidia are intracellular parasites, with over 1200 species belonging to 143 genera described to date. They are opportunistic pathogens in humans and can cause chronic diarrhoea in immunosuppressed patients. Both Enterocytozoon bieneusi and Encephalitozoon intestinalis cause intestinal disease, with Enterocytozoon bieneusi more commonly identified in patients with human immunodeficiency virus (HIV) infection. In this study, intestinal microsporidial clinical isolates from patients in Sydney, Australia, were genotyped. All specimens were from HIV-infected men with low CD4(+) T-cell counts (<100 cells mm(-3)). Genotyping of the internal transcribed spacer regions of the rRNA gene showed the presence of only one genotype, the anthroponotic Enterocytozoon bieneusi genotype B strain. This study thus highlighted the limited genetic diversity among Australian Enterocytozoon bieneusi isolates, and it is hypothesized that, due to the reduced incidence of microsporidia and the subsequent reduction in the human reservoir of the anthroponotic genotype B, locally acquired intestinal microsporidiosis will rarely be seen in HIV-infected persons undergoing highly active antiretroviral therapy in the future in Australia.
微孢子虫是细胞内寄生虫，迄今为止已描述了属于143个属的1200多种。它们是人类的机会性病原体，可导致免疫抑制患者出现慢性腹泻。比氏肠微孢子虫和肠道脑炎微孢子虫均可引起肠道疾病，其中比氏肠微孢子虫在人类免疫缺陷病毒（HIV）感染患者中更常见。在本研究中，对来自澳大利亚悉尼患者的肠道微孢子虫临床分离株进行了基因分型。所有标本均来自CD4(+) T细胞计数低（<100个细胞/mm(-3)）的HIV感染男性。rRNA基因内部转录间隔区的基因分型显示仅存在一种基因型，即人源性病原体比氏肠微孢子虫基因型B菌株。因此，本研究突出了澳大利亚比氏肠微孢子虫分离株之间有限的遗传多样性，并且据推测，由于微孢子虫发病率降低以及随后人源性病原体基因型B的宿主减少，在澳大利亚未来接受高效抗逆转录病毒治疗的HIV感染者中，很少会见到本地获得性肠道微孢子虫病。
