2014-2016年柳州市重症手足口病柯萨奇病毒A2型病毒株基因特征分析

Genetic characteristics of coxsackievirus A2 isolated from severe hand,foot and mouth disease from 2014 to 2016 in Liuzhou city of China

目的了解2014-2016年柳州地区重症手足口病肠道病毒A2型病原基因的特征。方法收集2014年1月至2016年12月手足口病重症儿童样本176份,提取病毒核酸,采用实时荧光逆转录-聚合酶链反应筛选,获得阳性病毒株。采用RT-PCR法扩增病毒5′UTR-VP4-VP2区序列,PCR阳性扩增产物进行测序,经Blast比对确定病毒基因型,并与国内外代表株进行核苷酸同源性比较,构建系统进化树。结果本研究共检出41株非CV-A16、非EV-A71毒株,其中25株病毒株为CV-A2型(25/41,61.0%)。同源性比对及系统进化分析显示,25株CV-A2型病毒株之间核苷酸同源性为76.8%~99.9%,与原始株CVA2Fleetwood同源性为64.6%~80.5%。结论 2014-2016年柳州市儿童重症手足口病CV-A2病毒成为非CV-A16、非EV-A71型别的重要病原,CV-A2型与原始株遗传距离较远,CV-A2型之间同源性较高且分布集中,构成一个独立的进化分支。需加强对CV-A2型肠道病毒株的持续监测和分子特征分析。

Objective To study the genetic characteristics of sever hand, foot and mouth disease （HFMD） from 2014 to 2016 in Liuzhou city of China. Methods A total of 176 samples from children with severe HFMD during January 2014 and December 2016 were collected. Virus RNA in the sample was extracted and the full-length 5＇UTR-VP4 VP2 gene was amplified by reverse transcription-polymerase chain reaction （RT- PCR） and sequenced. Virus genotypes were identified by using Blast software. The homology of 5＇UTR-VP4- VP2 gene of coxsaekievirus （CV） -A2 and the phylogenetic evolution tree was performed using DNAStar5.0 and MEGAS. 0 software, accordingly. Results Forty-one of non enterovirus （EV） -A71 and CV-A16 stains were detected and 25 CV-A2 strain isolates were identified （25/41, 61.0%）. The nucleotide homology among these 25 CV-A2 strains was 76.8%-99.9%. The nueleotide homology of the 25 CV-A2 strains with the origi nal CV-A2 Fleetwood strain was 64.6%-80.5%. Conclusions The main pathogens of the children with se- vere HFMD from 2014 to 2016 in Liuzhou city of China was CV-A2 but not CV-A16 or EV-A71. The genetic distances of CV-A2 stains were higher than the original CV-A2 Fleetwood strain. The homology of CV-A2 stains were similar, indicating an independent evolutionary branch in the evolutionary tree.