北京市朝阳区2012-2015年柯萨奇A2型肠道病毒的基因特征分析

Genetic analysis of the coxsackievirus A2 strains isolated in Chaoyang district of Beijing from 2012 to 2015

目的了解北京市朝阳区手足口病相关柯萨奇A2型肠道病毒(coxsackievirus A2,CV-A2)的基因特征。方法采用5′端非编码区(5′UTR)和VP2基因测序的方法鉴定CV-A2病毒;对所有CV-A2病毒进行VP1全序列测序,对部分毒株进行编码蛋白全序列测序,并将测得的序列与NCBI数据库中国内外的序列进行比对,构建系统进化树,进行基因特征及分子流行病学分析。结果 2012-2015年本地区共计检出6株CV-A2病毒。基于VP1分型,6条本研究的序列分别为D1亚型(5条)和D2亚型(1条)。6条VP1序列的核苷酸一致性为93.4%~98.5%,与原型株Fleetwood (基因库编号:AY421760)的核苷酸一致性为80.5%~81.6%。与国外VP1氨基酸序列比对显示有6个主要变异位点。在编码蛋白序列的P2和P3区发现与CV-A16、CV-A4和CV-A14型肠道病毒有基因重组。结论 2012-2015年北京市朝阳区CV-A2病毒有2种基因亚型,以D1亚型为主。本地区的CV-A2病毒发生了亚型转换和基因重组,应加强CV-A2病毒的持续监测和基因特征分析。

Objective To analyze the genetic characteristics of coxsackievirus A2(CV-A2)strains isolated from patients with hand,foot and mouth disease(HFMD)in Chaoyang district of Beijing. Methods CV-A2 strains were identified by 5′UTR and VP2 sequencing.RT-PCR was used to amplify the complete protein-coding and VP1 sequences.Nucleotide homogeneity and phylogenetic tree of protein-coding and VP1 sequences were analyzed using the MEGA 5.0 software. Results Six CV-A2 strains were detected during 2012-2015.The Chaoyang strains were grouped as D1 and D2 sub-genotypes based on the VP1 sequencing.The VP1 sequence homogeneity of the six CV-A2 strains were 93.4%-98.5%,and the homogeneity between the Chaoyang CV-A2 and the prototype strain Fleetwood(AY421760)were 80.5%-81.6%.Six amino acid mutation sites were found based on the VP1 protein analysis.Intertypic recombination was found between the Chaoyang strains and the CV-A16,CV-A4,CV-A14 strains at the P2 and P3 regions. Conclusions Two subgenotypes(D1 and D2)of CV-A2 were found in Chaoyang district of Beijing during the period of 2012 to 2015 with the D1 subgenotype was the predominant strain,and recombination and subgenotype replacement occurred.