2018年济南市14株柯萨奇病毒A组6型VP1基因特征分析

目的 分析济南市导致手足口病(hand, foot and mouth disease, HFMD)的柯萨奇病毒A组6型(Coxsackievirus A6, CVA6)分离株VP1基因特征及氨基酸变异。方法 2018年济南市HFMD常规监测病例样本经实时荧光RT-PCR检测，随机选择部分CVA6核酸阳性样本进行细胞分离鉴定，扩增阳性分离株VP1基因序列并进行同源性比较、氨基酸变异及系统进化分析。结果 2018年共检测652份样本，其中CVA6核酸阳性率为47.85%（312/652），远高于人肠道病毒A组71型（human enterovirus A 71, EV71）（7.06%, 46/652）和柯萨奇病毒A组16型(Coxsackievirus A16, CVA16)（8.44%,55/652 ），为济南市HFMD最主要病原体。通过细胞分离成功获得14株CVA6病毒，经VP1基因系统进化分析显示，济南市CVA6分离株均为基因D5亚型，VP1基因核苷酸及氨基酸序列同源性分别为94.2%~100%和98.0%~100%，与2017年广东株（GenBank 登录号MG385796、MG385815）、广西株（GenBank 登录号MH018512）、云南株（GenBank 登录号LC413143）及2014年江西株（GenBank 登录号KY913482）等亲缘关系较近。VP1蛋白主要存在V174I等位点变异，与国内流行的D5亚型基本一致。结论 2018年CVA6病毒为导致济南HFMD的主要病原，与广东、广西、云南和江西等省分离株亲缘关系较近，属于我国目前流行的基因D5亚型。

Characteristics of VP1 gene in 14 coxsackievirus A6 stains in Jinan, 2018

To investigate the VP1 gene characteristics and amino acid variation of Coxsackievirus A6(CVA6) isolated from hand, foot and mouth disease(HFMD) patients in Jinan. Methods The samples collected from patients with HFMD in Jinan city in 2018 were analyzed using real-time RT-PCR and some of the CVA6 nucleic acid positive samples chosen randomly were pretreated to inoculate cells. The whole VP1 gene sequences of all CVA6 stains successfully isolated in cells were amplified and sequined, then the homology consistency of nucleotide and variation of amino acid and phylogenetic tree were conducted by bioinformatics analysis. Results A total of 652 stool specimens were collected and detected in 2018. The CVA6 positive rate was 47.85%(312/652), which was significantly higher than human enterovirus A 71(7.06%,46/652) and coxsackievirus A16(8.44%,55/652). All the 14 CVA6 strains isolated from Jinan were belonged to D5 sub genotype, the homology of their VP1 nucleotide and deduced amino acids were 94.2%-100% and 98.0%-100%, respectively. The Jinan CVA6 were closely related to strains detected in Guangdong(GenBank accession no: MG385796,MG385815), Guangxi(MH018512), Yunnan(LC413143) and Jiangxi(KY913482). There were some amino acid mutations such as V174 I in VP1 protein of Jinan CVA6 strains, which was consistent with the D5 sub genotype in our country. Conclusion The CVA6 is the mainly responsible virus for HFMD in Jinan city. All the 14 isolated strains belong to D5 sub genotypes and share high homology with the strains isolate form Guangdong, Guangxi, Yunnan and Jiangxi areas.