Niyyati Maryam, Karamati Seyed Ahmad, Lorenzo Morales Jacob, Lasjerdi Zohreh
Parasitol Res. 2016 Feb;115(2):541-5. doi: 10.1007/s00436-015-4770-y.
Balamuthia mandrillaris is an opportunistic free-living amoebae (FLA) which has been reported as the causative agent of the fatal Balamuthia amoebic encephalitis (BAE). Currently, the transmission dynamics of this pathogen remain poorly understood although the organism has been associated with soils, and thus, soil exposure has been identified as a risk factor for this pathogenic amoeba. Nevertheless, environmental isolation of B. mandrillaris is a rare event and strains of this amoebic species have been isolated from soil and dust sources only in seven previous reports (Iran, Mexico, USA, Peru, Costa Rica, Guinea Bissau, and Jamaica). In Iran, a previous study reported the isolation of B. mandrillaris from dust collected in the city of Tehran and free of known infectious involvement. Therefore, in this work, 55 soil samples collected from public and recreational areas of East Azerbaijan, North-Western Iran, were investigated for the presence of this pathogen. Samples were cultured in 2% non-nutrient agar plates and were monitored for the presence of B. mandrillaris-like trophozoites and/or cysts. Those samples that were positive for these amoebae by microscopic criteria were then confirmed by PCR amplification and DNA sequencing of the mitochondrial 16S ribosomal DNA (rDNA) of B. mandrillaris. The obtained results revealed the presence of this emerging pathogen in 5 of 55 samples included in the study. Homology analysis of the obtained DNA sequences revealed high similarity with previously isolated strains from clinical and environmental sources. To the best of our knowledge, this is the first report on the isolation of B. mandrillaris from soil sources in Iran related to human activity and the second time that this pathogen is isolated from the environment in this country.
棘阿米巴属是一种机会性自由生活阿米巴（FLA），已被报道为致命性棘阿米巴性脑炎（BAE）的病原体。目前，尽管该生物体与土壤有关，但其传播动态仍知之甚少，因此，土壤暴露已被确定为这种致病性阿米巴的一个风险因素。然而，棘阿米巴的环境分离是一个罕见事件，此前仅有七篇报道（伊朗、墨西哥、美国、秘鲁、哥斯达黎加、几内亚比绍和牙买加）从土壤和灰尘源中分离出这种阿米巴物种的菌株。在伊朗，之前的一项研究报道从德黑兰市收集的无已知感染源的灰尘中分离出了棘阿米巴。因此，在这项工作中，对从伊朗西北部东阿塞拜疆省的公共和娱乐区域采集的55份土壤样本进行了该病原体的检测。样本在2%非营养琼脂平板上培养，并监测是否存在类似棘阿米巴的滋养体和/或包囊。通过显微镜标准对这些阿米巴呈阳性的样本随后通过棘阿米巴线粒体16S核糖体DNA（rDNA）的PCR扩增和DNA测序进行确认。所获得的结果显示，在该研究纳入的55份样本中有5份存在这种新出现的病原体。对所获得的DNA序列进行的同源性分析显示，与之前从临床和环境来源分离的菌株具有高度相似性。据我们所知，这是关于在伊朗从与人类活动相关的土壤来源中分离出棘阿米巴的首次报道，也是该国第二次从环境中分离出这种病原体。
