Departamento de Microbiologia, Imunologia e Parasitogia, Instituto de Ciências Básicas da Saúde, Setor de Parasitologia, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS 90050-170, Brazil.
Curr Microbiol. 2011 Nov;63(5):464-9. doi: 10.1007/s00284-011-0003-5. Epub 2011 Sep 1.
A total of 136 samples of tap water were collected from state and municipal schools between March and November 2009. The samples were filtered through cellulose nitrate membranes that were seeded at non-nutrient agar 1.5% containing an overlayer of Escherichia coli suspension. Thirty-one (22.79%) tap water samples investigated were found positive for free-living amoebae (FLA). From these, 13 presented as FLA that seems to belong to the genus Acanthamoeba. All samples of FLA were cloned and identified as belonging to the genus Acanthamoeba by the morphology of cysts and trophozoites and by PCR using genus-specific primers that amplify the ASA.S1 region of 18S rDNA gene. Physiological tests of thermotolerance and osmotolerance were used to evaluate the pathogenicity of the isolates. The sequencing analysis by comparing the sequences submitted to GenBank, showed genotype distribution into groups T2, T2/T6, T6, and T4. In tests of thermotolerance and osmotolerance, 50% of the isolates had a low pathogenic potential. The results indicated the presence of Acanthamoeba in tap water in Rio Grande do Sul, Brazil, revealing its importance and the need for more epidemiological studies to determine their distribution in the environment and its pathogenic potential.
2009 年 3 月至 11 月，共从州立和市立学校采集了 136 份自来水样本。这些样本通过纤维素硝酸酯膜过滤，该膜在含有大肠杆菌悬浮液覆盖层的非营养琼脂 1.5%上播种。调查的 31 份（22.79%）自来水样本中发现自由生活阿米巴（FLA）呈阳性。其中，13 个似乎属于棘阿米巴属的 FLA。所有 FLA 样本均通过克隆和鉴定，根据囊和滋养体的形态以及使用针对属的引物扩增 18S rDNA 基因的 ASA.S1 区来鉴定为棘阿米巴属。耐热性和耐渗性的生理试验用于评估分离株的致病性。通过与 GenBank 提交的序列进行比较的测序分析，显示基因型分布为 T2、T2/T6、T6 和 T4 组。在耐热性和耐渗性测试中，50%的分离株具有低致病性潜力。结果表明，巴西南里奥格兰德州自来水中存在棘阿米巴，这表明其重要性以及需要进行更多的流行病学研究来确定其在环境中的分布及其潜在的致病性。
