北京市丰台区2016年-2017年肠道病毒A71型基因特征分析

Genetic characteristics and analysis of enterovirus group A type 71 during 2016-2017 in Fengtai District, Beijing

目的分析北京市丰台区2016年-2017年肠道病毒A组71型(EVA71)分离株VP1区的基因特征,为手足口病的防治提供参考。方法用荧光定量RT-PCR法对2016年-2017年丰台区手足口病患者咽拭子标本进行EVA71核酸检测和病毒分离,分离到的毒株进行VP1区基因扩增,并对扩增产物进行序列测定和分析。结果 2016年-2017年共分离到26株EVA71。核苷酸序列分析发现,26株EVA71的VP1区均有6个散在位点(43、58、164、184、240、249)存在共变异;23株EVA71的VP1区在145位氨基酸均为谷氨酸(Glutamic acid, Glu);6株EVA71的VP1区在293位氨基酸由丙氨酸突变为丝氨酸;核苷酸序列分析结果表明,26株EVA71与C4a亚型代表株核苷酸同源性最高(94.8%~98.3%)与C4亚型代表株处于同一分支,并在C4a进化分支的不同簇中。结论北京市丰台区EVA71分离株为C4亚型C4a进化分支。145位和293位氨基酸位点上氨基酸的改变对病毒的意义尚需进一步研究。

Objective To investigate the genetic characteristics of enterovirus group A type 71(EVA71)in Fengtai District,Beijing,so as to provide reference for the control and prevention of hand,foot and mouth diasease(HFMD).Methods Virus isolation and nucleic acid detection were carried out on positive EVA71 swab specimens by real-time reverse transcript-polymerase chain reaction(RT-rPCR)in Fengtai District,Beijing from 2016 to 2017.Then the sequences of VP1 encoding region of EVA71 strains were amplified and analyzed.Results 26 strains of EVA71 were isolated.Common variation was observed in six scattered sites(43,58,164,184,240,249)on the VP1 encoding region of all the 26 EVA71 strains;145 amino acids were glutamic acid(Glu)in the VP1 region of 23 EVA71;293 amino acids were mutated from alanine to serine in the VP1 region of 6 EVA71;nucleotide sequence analysis showed that 26 strains of EVA71 had the highest nucleotide homology with the representative strain of C4a subtype(94.8%-98.3%),which was in the same branch as C4 subtype representative strain,and located in different clusters of the C4a evolution branch.Conclusion The EVA71 strains isolated from Fengtai District belongs to C4a evolution branch of subtype C4.The significance of amino acid changes at the 145 and 293 amino acid sites needs further study for the virus.