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

Abstract: Objective Objective To initially understand the infection status and the molecular characteristics of Giardia in clinical di? arrheal patients. Methods 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 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 Conclu? ? sions 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