Mirahmadi H, Rahmati-Balaghaleh M, Darabi E, Zarean M, Sharifi Y, Yousefnia H, Etemadi S, Parandin F, Askari Z
Infectious Disease and Tropical Medicine Research Center, Research Institute of Cellular and Molecular Sciences in Infectious Diseases, Zahedan University of Medical Sciences, Zahedan, Iran.
Department of Parasitology and Mycology, Faculty of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.
Arch Razi Inst. 2025 Feb 1;80(1):61-67. doi: 10.32592/ARI.2025.80.1.61. eCollection 2025 Feb.
Blastocystis spp. is a zoonotic anaerobic parasite that has been identified in the large intestine of humans and many vertebrates. It is predominantly encountered in individuals with frequent contact with animals. The present study aims to identify the prevalence of Blastocystis spp. and its common genotypes in children with clinical symptoms of diarrhea in the city of Zahedan, located in the southeast of Iran. A cross-sectional descriptive study was conducted on 60 children under ten years of age with gastrointestinal symptoms, especially diarrhea. Following the collection of samples, stool samples were subjected to direct stool testing for the initial diagnosis. Following this, a microscopic diagnosis was made, after which DNA was extracted and a Polymerase Chain Reaction (PCR) test with a small subunit ribosomal RNA (SSU rRNA) gene target was performed. The PCR products were then purified and sequenced. The resulting nucleotide sequences were then subjected to a thorough review using Chromas biotechnology software version 2.4 and CLC genomic work bench software 11. The alignment of the nucleotide sequences was subsequently facilitated by utilizing the BLAST database, and these sequences were then compared with the reference genotypes of Blastocystis spp. that are stored within the gene bank. The genotyping of the sequences was conducted using CLC genomic work bench software 11, and a phylogenetic tree was constructed using MEGA7 software with the Neighbor-Joining statistical method, which applied the Kimura 2-parameter method. Out of the 60 cases that were examined, 5 children (8.33%) were found to be positive by direct microscopic and PCR tests, where a 500 (479) bp fragment in the SSU-rRNA target was detected. Subsequent genetic analysis identified four distinct subtypes, including subtypes 1, 2, 3, and 5. The percentage of nucleotide identity with the sequences in the gene bank was found to be between 93 and 100%. Given the presence of subtypes 3 and 5 in the study and the evidence of their zoonotic nature, it can be concluded that examining parasite dynamics and epidemiological principles can be effective in the control strategy.
芽囊原虫属是一种人畜共患的厌氧寄生虫，已在人类和许多脊椎动物的大肠中被发现。它主要出现在经常接触动物的个体中。本研究旨在确定位于伊朗东南部扎黑丹市有腹泻临床症状的儿童中芽囊原虫属的流行率及其常见基因型。对60名10岁以下有胃肠道症状尤其是腹泻的儿童进行了一项横断面描述性研究。采集样本后，对粪便样本进行直接粪便检测以进行初步诊断。在此之后，进行显微镜诊断，然后提取DNA并进行以小亚基核糖体RNA（SSU rRNA）基因靶点的聚合酶链反应（PCR）检测。然后对PCR产物进行纯化和测序。随后使用Chromas生物技术软件2.4版和CLC基因组工作台软件11对所得核苷酸序列进行全面审查。利用BLAST数据库促进核苷酸序列的比对，然后将这些序列与基因库中存储的芽囊原虫属参考基因型进行比较。使用CLC基因组工作台软件11对序列进行基因分型，并使用MEGA7软件采用邻接法统计方法构建系统发育树，该方法应用了Kimura双参数法。在60例被检查的病例中，有5名儿童（8.33%）通过直接显微镜检查和PCR检测呈阳性，在SSU - rRNA靶点中检测到一个500（479）bp的片段。随后的基因分析确定了四种不同的亚型，包括亚型1、2、3和5。发现与基因库中序列的核苷酸同一性百分比在93%至100%之间。鉴于研究中存在亚型3和5以及它们人畜共患性质的证据，可以得出结论，研究寄生虫动态和流行病学原理在控制策略中可能是有效的。
