First detection and molecular identification of Entamoeba bovis from Japanese cattle
First detection and molecular identification of Entamoeba bovis from Japanese cattle
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DOI：
10.1007/s00436-017-5689-2
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发表时间：
2018-01-01
影响因子：
2
通讯作者：
Sasai, Kazumi
中科院分区：
文献类型：
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作者：
Matsubayashi, Makoto;Matsuura, Yuu;Sasai, Kazumi
到目前为止，内阿米巴物种已根据形态学（例如成熟包囊中的细胞核数量及其宿主）进行分类。使用最近开发的分子工具，反刍动物内阿米巴属。目前分为四种物种/基因型：牛大肠杆菌和内阿米巴核糖体谱系 (RL) 1、2 和 4。然而，反刍动物内阿米巴的分布或致病性尚未得到充分记录。在本研究中，我们通过浮选法、PCR 和测序分析，检查了 2016 年至 2017 年从日本六个农场收集的总共 25 份粪便和 7 份环境样本。因此，我们通过显微镜检查，在 25 个牛样本中的 18 个以及 7 个环境样本（包括土壤和饮用水）中的 4 个中检测到了内阿米巴包囊。在后续检查中，发现内阿米巴阳性牛在8个多月的时间内排出包囊而没有任何临床症状。通过PCR进行分子鉴定，成功对10头牛和一份土壤样品中的分离株进行测序，并形成牛大肠杆菌簇，并在系统发育分析中与其他内阿米巴物种/基因型（例如RL1-4）分离。据我们所知，这是日本首次关于牛大肠杆菌的报告，我们的结果可能表明牛大肠杆菌不具有致病性。
Thus far, Entamoeba species have been classified based on morphology such as the number of nuclei in mature cysts and their hosts. Using recently developed molecular tools, ruminant Entamoeba spp. are currently classified into four species/genotypes: E. bovis and Entamoeba ribosomal lineages (RL) 1, 2, and 4. However, the distribution or pathogenicity of ruminant Entamoeba has not been well documented. In the present study, we examined a total of 25 fecal and seven environmental samples collected from six farms in Japan from 2016 to 2017 by the floatation method and PCR and sequencing analyses. Consequently, we detected Entamoeba cysts in 18 of 25 cattle samples and four of the seven environmental samples, including soil and drinking water, by microscopic examinations. In sequential examinations, Entamoeba-positive cattle were found to shed cysts without any clinical symptoms for more than 8 months. By PCR for molecular identification, isolates in ten cattle and one soil sample were successfully sequenced and formed a cluster of E. bovis, which was separated from those of other Entamoeba species/genotypes such as RL1-4 in phylogenetic analysis. To our knowledge, this is the first report about E. bovis in Japan, and our results may implicate that E. bovis is not pathogenic.