Peña Sebastián, Carrasco Gabriela, Rojas Pamela, Castillo Douglas, Ozaki Luiz S, Mercado Rubén
Parasitology Unit, Faculty of Medicine, Universidad de Chile, Santiago, Chile.
Department of Nutrition, Faculty of Medicine, Universidad de Chile, Santiago, Chile.
Parasite Epidemiol Control. 2019 Nov 21;8:e00125. doi: 10.1016/j.parepi.2019.e00125. eCollection 2020 Feb.
BACKGROUND & METHODS: sp. is one of the most prevalent unicellular eukaryote of the human large intestine in Chile and worldwide. It is classified in subtypes (STs), where using the polymorphic sequences of its genes currently recognizes 22. STs 1-9 and ST12 have been reported in humans. It has been hypothesized that different STs of sp. differentially affect the clinical severity of the digestive disease in Irritable Bowel Syndrome (IBS) patients, but more studies ar4e needed to establish this statement. To contribute in the elucidation of the potential relationship between sp. subtypes and IBS severity, 37 IBS patient fecal samples were collected at hospitals in Santiago (Chile) and were screened for the presence of vacuolated forms of sp. by using conventional microscopy. Positive samples were submitted to PCR and sequencing for determining STs. The same procedure was performed in fecal samples from five non-IBS sp. carriers for preliminary comparative purpose.
Four out of the 37 samples from the IBS patients were found positive for sp. (10.81%) by using microscopy. The presence of this microorganism in these four samples were confirmed by PCR and sequencing. Subtypes and their respective closest match alleles were searched and the ST1, ST2 and ST4 subtypes were found in these patients. ST4 subtype is scarcely detected in South America countries, being reported previously only in Colombia and Brazil. In this ST4 subtype we determined the allele 42 which is the most frequent allele observed in human isolates. In the non-IBS individuals' carriers, three subtypes were found: ST1, ST2 and ST3, even belonging to the same family group. Closest match alleles: 2, 12 and 34 here detected were also commonly reported globally. Instead of the small number of IBS patients studied here, the frequency of blastocystosis detected (10.81%) was lower than the prevalence of sp. infections described for the Chilean general population (30.4%). In Chile, clear correlation of sp. subtypes and IBS severity is still lacking with this study but it may lead and contribute to a better understanding of its pathogenicity and worldwide epidemiology.
[某种生物名称]是智利乃至全球人类大肠中最普遍的单细胞真核生物之一。它被分为不同的亚型(STs),目前利用其[相关基因名称]的多态性序列可识别出22种亚型。已在人类中报道了ST1 - 9和ST12亚型。据推测,[某种生物名称]的不同STs对肠易激综合征(IBS)患者消化系统疾病的临床严重程度有不同影响,但需要更多研究来证实这一说法。为有助于阐明[某种生物名称]亚型与IBS严重程度之间的潜在关系,在智利圣地亚哥的医院收集了37份IBS患者的粪便样本,并通过传统显微镜检查筛选是否存在[某种生物名称]的空泡形式。阳性样本进行PCR和测序以确定STs。为进行初步比较,对5名非IBS[某种生物名称]携带者的粪便样本进行了相同操作。
通过显微镜检查,在37份IBS患者样本中有4份被发现[某种生物名称]呈阳性(10.81%)。这4份样本中该微生物的存在通过PCR和测序得到证实。搜索亚型及其各自最匹配的等位基因,在这些患者中发现了ST1、ST2和ST4亚型。ST4亚型在南美国家很少被检测到,此前仅在哥伦比亚和巴西有报道。在这个ST4亚型中,我们确定了等位基因42,它是在人类[某种生物名称]分离株中观察到的最常见等位基因。在非IBS个体携带者中,发现了三种亚型:ST1、ST2和ST3,它们甚至属于同一家族组。这里检测到的最匹配等位基因2、12和34在全球也普遍有报道。尽管本研究中研究的IBS患者数量较少,但检测到的芽囊原虫病频率(10.81%)低于智利普通人群中描述的[某种生物名称]感染患病率(30.4%)。在智利,本研究仍缺乏[某种生物名称]亚型与IBS严重程度之间的明确相关性,但它可能有助于更好地理解其致病性和全球流行病学。