Abstract:

［Abstract］ Objective To initially understand the infection status and the molecular characteristics of Giardia in clinical di? arrheal patients. Methods A total of 95 stool samples were collected from the clinical diarrheal patients admitted in a hospital in Shanghai from May to July，2014，and the Giardia cysts in the samples were examined by an optical microscope. Then the tpi gene of Giardia in the positive samples were amplified by using the nested?PCR method，and the PCR products were sequenced and analyzed by using BLAST，ClustalX 1.83，and the phylogenetic tree was drawn by using MEGA6.0 software. Results Only one patient was infected with Giardia and the positive detection rate was 1.05%. The Giardia cysts in the fecal specimen were seen clearly under the microscope. Through the identification by PCR，the amplified fragment was about 530 bp，and the se? quencing analysis indicated it was Giardia and which was further identified as assemblage B by drawing phylogenetic tree based on tpi gene. Meanwhile，the sequence had 100% homology with the reported sequence from human（KF271445）. Conclu? sions Giardia infection can occur in the clinical diarrheal patients. The study could provide more data for understanding the ge? netic characteristics of Giardia and the epidemiological study of giardiasis.

Key words: Diarrhea, Infection, Giardia, Morphology, Molecular characteristic, Nested PCR, Phylogenetic tree

摘要：

［摘要］ 目的 初步了解临床腹泻患者贾第虫的感染情况及分子特征。方法 以2014年5?7月上海市某医院临床腹泻患者为研究对象，收集粪便样本95份，进行卢戈氏碘液染色，用光学显微镜检查贾第虫包囊。采用巢式PCR法扩增贾第虫磷酸丙糖异构酶基因（tpi），扩增产物测序后用BLAST、ClustalX 1.83和MEGA6.0软件进行同源性和系统发育分析。结果 通过形态学观察发现1例腹泻患者感染贾第虫，阳性检出率为1.05%。其粪便样本经卢戈氏碘液染色后显微镜下可见清晰的包囊。对样本进行PCR检测，扩增片段大小约为530 bp，测序结果显示为贾第虫。经序列比对分析，并以tpi 基因构建系统发育树，分析鉴定该分离株为集聚体B，与已报道的人源贾第虫分离株（KF271445）同源性为100%。结论 临床腹泻患者中存在贾第虫感染，本研究结果可为了解贾第虫基因型特点及贾第虫病流行病学研究提供参考。

关键词: 腹泻, 感染, 贾第虫, 形态学, 分子特征, 巢式PCR, 系统进化树