Background

Blastocystis is a unicellular protozoan and one of the most common parasites found in humans and many animals' intestinal tract. The present study aimed to compare the genotypes of Blastocystis infecting cattle and humans in the south of Iran.

Methods

A total of 100 human stool samples and 75 cattle stool samples were microscopically examined for Blastocystis infection. DNA was extracted from thirty-eight microscopically positive samples (13 humans and 25 cattle). PCR was performed on positive samples targeting the Blastocystis-specific SSU rDNA gene. PCR products of eight humans and eleven cattle samples were sequenced and compared with available reference sequences in GenBank by BLAST queries. Genetic diversity was measured for Blastocystis subtypes in human and cattle, based on haplotype and nucleotide diversities.

Results

The PCR detected Blastocystis in ten humans and twenty-four cattle samples. Blastocystis subtypes 1, 2, and 6 were found in humans whereas subtypes 5 and 10 were found in cattle. Subtype (ST) 2 was the most predominant subtypes in humans whereas, in cattle specimens, the ST5 was the most dominant subtype. Based on the Blastocystis sequences of SSU rDNA, 68 sites were polymorphic and 49 sites were parsimony informative, resulting in the identification of 15 haplotypes, 10 haplotypes in the cattle and 5 in humans. No haplotype was shared between cattle and human parasites.

Conclusion

Human-derived Blastocystis subtypes were different from cattle subtypes in southern Iran. Nevertheless, subtype 5 in cattle can be a risk factor for human infection.

中文翻译：

---

在伊朗南部感染牛和人的Blastocystis基因分型比较。

背景

囊藻是一种单细胞的原生动物，是人类和许多动物肠道中最常见的寄生虫之一。本研究旨在比较感染伊朗南部牛和人的Blastocystis基因型。

方法

在显微镜下检查了总共100份人类粪便样本和75份牛粪便样本是否存在Blastocystis感染。从38个镜检阳性样本（13人和25头牛）中提取DNA。对靶向芽孢杆菌特异性SSU rDNA基因的阳性样品进行PCR 。对8个人和11牛样品的PCR产物进行测序，并通过BLAST查询与GenBank中可用的参考序列进行比较。基于单倍型和核苷酸多样性，测量了人和牛中的囊胚亚型的遗传多样性。

结果

PCR检测到十个人和二十四头牛样品中的囊胚芽孢杆菌。在人中发现了囊胚亚型1、2和6，而在牛中发现了亚型5和10。亚型（ST）2是人类中最主要的亚型，而在牛标本中，ST5是最主要的亚型。根据SSU rDNA的囊胚序列，有68个位点是多态性的，有49个位点是简约信息，从而鉴定出15个单倍型，牛的10个单倍型和人类的5个单倍型。牛和人类寄生虫之间没有共享单倍型。

结论

人源性胚芽孢杆菌亚型不同于伊朗南部的牛亚型。然而，牛中的亚型5可能是人类感染的危险因素。