云南省重症手足口病EV-A71型病毒VP1基因遗传特征分析

Analysis of VP1 genetic characteristics of enterovirus A71 isolated from severe patients with hand,foot and mouth disease in Yunnan province of China

目的分析云南省重症手足口病(hand,foot and mouth disease,HFMD)患者肠道病毒71型(enterovirus A71,EV-A71)的VP1基因遗传特征。方法对收集的重症病例粪便样本进行荧光RT-PCR鉴定和病毒分离培养,并对鉴定为EV-A71型的毒株进行VP1区的核酸扩增和序列测定,与其他地区和国家的重症参考株构建遗传进化树,进行遗传特征分析。结果本研究共收集到了10份EV-A71型重症患者样本,10份EV-A71型分离株均属于C4a亚型,并在遗传进化树上与其他地区和国家的重症分离株明显聚集成簇,存在氨基酸突变位点。结论重症手足口病EV-A71病毒在进化树上聚集为2簇,10份云南分离株主要聚集在簇Ⅱ分支,其VP1区氨基酸突变位点与国内及国际其他肠道病毒71型的突变位点有相似性。

Objective To analyze the VP1 genetic characteristics of enterovirus A71 strains isolated from severe cases of hand,foot and mouth disease（HFMD） in Yunnan. Methods Enterovirus isolation was performed in RD cell lines from the collected stool specimens. EV-A71 strains were identified by real-time RT-PCR from the positive cultures. The homology of nucleotide and amino acid sequences were analyzed with Gen Bank reference strain. Results Totally 10 EV-A71 strains were isolated and identified from severe patients in this study. The complete VP1 sequences of 10 EV-A71 strains were determined. These EV-A71 strains belong to C4 a subtype that co-evolved with isolates from other districts in mainland of China. Phylogenetic tree analysis revealed that 10 EV-A71 strains were clustered into branches with the Gen Bank reference strain. Conclusions The EV-A71 strains isolated from severe patients with HFMD clustered into two branches,and the 10 EV-A71 strains in this study mainly clustered in the clusterⅡ branch. The amino acid mutation sites of VP1 gene revealed some similarity between 10 EV-A71 strains and the Gen Bank reference strain.