Department of Biology, College of Sciences, Mustansiriyah University, Baghdad, Iraq.
Department of Biotechnology, College of Sciences, Diyala University, Diyala, Iraq.
Ann Parasitol. 2022;68(2):275-286. doi: 10.17420/ap6802.433.
The parasites that belong to the genus Blastocystis are the most common intestinal parasite detected in a wide range of hosts including humans. Although the pathogenicity of these parasites remains controversial, many studies confirmed their pathogenicity and some researchers strongly believe that the pathogenicity may be linked with specific subtypes of these parasites. The current study investigated the Blastocystis sp. subtypes recovered from individuals suffering from the irritable bowel syndrome (IBS) in comparison with those recovered from non-IBS subjects. Fresh stool samples were collected from each participant and processed during the same day of collection. Iodine wet mounts and trichrome stained smears prepared from fresh stool and sediment concentrates were microscopically examined for Blastocystis parasites. In addition, Jones's medium has been used in order to confirm the identification and also to get the genomic DNA from positive samples for PCR and sequencing. The culture was significantly more sensitive (P=0.0035) than the other identification methods, especially in IBS patients. Blastocystis was detected in 60.0% of patients with IBS and in 22.0% of non-IBS individuals and the difference between two groups was statistically significant (P=0.0001). Regarding the impact of age and gender on the prevalence of infection with Blastocystis, no significant differences were observed between IBS patients and non-IBS subjects except for the age group (10-30 years) where the non-IBS subjects were significantly more prone (P=0.0223) to the infection with this parasite than IBS patients. The abdominal pain and bloating were the leading symptoms. DNA sequencing and phylogenetic analysis of Iraqi Blastocystis isolates identified three subtypes (ST1, ST2 and ST3). Among these three subtypes, ST3 was significantly more prevalent (OR=8.5; P=0.0058) among IBS patients (60%) than non-IBS subjects (25%). In contrast, the dominance of ST1 was significantly higher (OR=7.0; P=0.0062) in the non-IBS subjects (70%) than their IBS patients counterparts (15%). As far as we know, this study is the first to deal with the genetic characterization of Blastocystis subtypes in an Iraqi population with and without IBS.
寄生物属 Blastocystis 中最常见的肠道寄生虫，在包括人类在内的广泛宿主中都有检测到。尽管这些寄生虫的致病性仍存在争议，但许多研究证实了它们的致病性，一些研究人员强烈认为，这些寄生虫的致病性可能与它们的特定亚型有关。本研究调查了从患有肠易激综合征（IBS）的个体中回收的 Blastocystis sp. 亚型与从非 IBS 个体中回收的亚型。从每位参与者采集新鲜粪便样本，并在采集当天进行处理。碘湿片和新鲜粪便及沉淀物浓缩物制备的三色染色涂片用显微镜检查 Blastocystis 寄生虫。此外，还使用了琼斯培养基来确认鉴定，并且从阳性样本中获得基因组 DNA 用于 PCR 和测序。与其他鉴定方法相比，该培养方法的灵敏度显著更高（P=0.0035），特别是在 IBS 患者中。Blastocystis 在 60.0%的 IBS 患者和 22.0%的非 IBS 个体中被检测到，两组之间的差异具有统计学意义（P=0.0001）。关于年龄和性别对 Blastocystis 感染流行率的影响，除了年龄组（10-30 岁）外，IBS 患者和非 IBS 个体之间没有观察到显著差异，在该年龄组中，非 IBS 个体感染这种寄生虫的可能性显著高于 IBS 患者（P=0.0223）。腹痛和腹胀是主要症状。对伊拉克 Blastocystis 分离株的 DNA 测序和系统发育分析鉴定出了三种亚型（ST1、ST2 和 ST3）。在这三种亚型中，ST3 在 IBS 患者（60%）中的流行率明显更高（OR=8.5；P=0.0058），而非 IBS 个体（25%）中流行率明显较低。相比之下，ST1 在非 IBS 个体（OR=7.0；P=0.0062）中的优势明显更高（70%），而在 IBS 患者（15%）中优势明显较低。据我们所知，这是首次在有和没有 IBS 的伊拉克人群中对 Blastocystis 亚型进行遗传特征分析的研究。
