Khosravinia Nazgol, Fata Abdolmajid, Moghaddas Elham, Hosseini Farash Bibi Razieh, Sedaghat Mohammad Reza, Eslampour Ali Raza, Jarahi Lida
Department of Medical Parasitology and Mycology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
Cutaneous Leishmaniasis Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
Iran J Parasitol. 2021 Jan-Mar;16(1):111-121. doi: 10.18502/ijpa.v16i1.5530.
The genus is a free-living opportunistic protozoan parasite, which widely distributed in soil and fresh water. keratitis, which causes a sight-threating infection of the cornea, is going to rise in Iran and worldwide. The aim of this study was to compare direct microscopy, culture and PCR for detection of spp in clinical samples and to determine the genotypes of spp by sequencing 18SrRNA gene.
Among patients clinically suspected to AK referred to a tertiary ophthalmology center at Mashhad, northeastern Iran. During 2017-18, twenty corneal scrapes specimens obtained. The samples were divided into three parts, subjected to direct microscopic examination, culture onto non-nutrient agar and PCR technique. Sensitivity, specificity, accuracy and likelihood ratio were evaluated.
Among 20 persons clinically suspected to amoebic keratitis, 13(69.2%) patients definitely diagnosed as keratitis. Wearing contact lens, eye trauma due to foreign particle and swimming in fresh water were the main predisposing factors. Most of patients suffered from pain and photophobia. Corneal ring infiltration and epithelial defect were common clinical sings. Direct examination had the lowest sensitivity and sensitivity of both Nelson-PCR and JDP-PCR methods were equal and highest. In addition, the results of sequencing identified that all strains belonged to T4 genotype.
Amoebic keratitis is a sporadic parasitic keratitis, which is mainly seen in contact lens user in Mashhad. PCR based on 18S ribosomal DNA with JDP primers is a reliable and highly sensitive method for diagnosis of keratitis in clinically suspected cases.
该属是一种自由生活的机会性原生动物寄生虫，广泛分布于土壤和淡水中。棘阿米巴角膜炎会导致威胁视力的角膜感染，在伊朗和全球范围内都呈上升趋势。本研究的目的是比较直接显微镜检查、培养和聚合酶链反应（PCR）用于检测临床样本中棘阿米巴属物种的效果，并通过对18SrRNA基因进行测序来确定棘阿米巴属物种的基因型。
在伊朗东北部马什哈德的一家三级眼科中心，对临床疑似棘阿米巴角膜炎的患者进行研究。在2017 - 2018年期间，获取了20份角膜刮片标本。将样本分成三部分，分别进行直接显微镜检查、接种到无营养琼脂上培养以及采用PCR技术。评估了敏感性、特异性、准确性和似然比。
在20名临床疑似阿米巴角膜炎的患者中，13例（69.2%）被明确诊断为棘阿米巴角膜炎。佩戴隐形眼镜、异物导致的眼外伤以及在淡水中游泳是主要的诱发因素。大多数患者有疼痛和畏光症状。角膜环形浸润和上皮缺损是常见的临床体征。直接检查的敏感性最低，尼尔森PCR（Nelson-PCR）和JDP-PCR方法的敏感性相同且最高。此外，测序结果表明所有菌株均属于T4基因型。
棘阿米巴角膜炎是一种散发性寄生虫性角膜炎，在马什哈德主要见于隐形眼镜使用者。基于带有JDP引物的18S核糖体DNA的PCR是临床疑似病例中诊断棘阿米巴角膜炎的可靠且高度敏感的方法。
