埃可病毒14型分离株VP1区序列基因特征分析

Genetic characteristics of the VP1 region of Echovirus 14 isolated strains

目的分析全球近30年埃可病毒14型(echovirus14,Echo14)分离株VP1区遗传进化规律,探索其分子流行病学特征。方法应用生物信息学软件,分析GenBank核苷酸数据库收录的全球Echo14分离株全长VP1区基因序列,构建系统进化树,比较分析分离株核苷酸和氨基酸同源性。采用Datamonkey在线软件筛选正向选择位点,采用Bioedit软件测算氨基酸置换熵值。结果共纳入Echo14分离株140株,毒株分离于1990—2019年,主要来自中国(占69.3%),主要分离自急性迟缓性麻痹监测样品(占72.1%)。分离株血清型由多到少依次为基因型D(占44.3%)、B(占30.0%)、C(占23.6%)和A(占2.1%),其中C和D型均流行于中国;分离株核苷酸和氨基酸同源性为80.0%和96.2%;发现1个正向选择位点和11个氨基酸易突变位点;核苷酸碱基总突变数6833 bp,总突变率为5.5%。结论Echo14流行水平较低,其分离株进化较为活跃,亲缘性关系较远,存在共循环流行特征。

Objective To analyze the genetic evolution of VP1 region of echovirus 14(Echo14)isolated strains and explore the molecular epidemiology characteristics.Methods The gene sequences of the full⁃length VP1 region of Echo14 isolates collected in the GenBank nucleotide database were used to construct a phylogenetic tree,compare and analyze the nucleotide and amino acid homology by Bioinformatics software.Datamonkey online software was used to screen the positive selection sites and Bioedit software was used to calculate the amino acid replacement entropy.Results A total of 140 Echo14 strains isolated from 1990 to 2019 were included,main⁃ly from samples of China(accounted for 69.3%)and acute delayed paralysis surveillance(accounted for 72.1%).The serotypes of the isolated strains in descending order were genotype D(accounted for 44.3%),B(accounted for 30.0%),C(accounted for 23.6%),and A(accounted for 2.1%);Both C and D subtypes were reported only in China.The average homology of nucleotide and amino acid between isolates was 80.0%and 96.2%,respectively;one positive selection site and 11 amino acid mutable sites were found.The total number of nucleotide base mutations was 6833 bp,and the total mutation rate was 5.5%.Conclusion The prevalence of Echo14 was at low level.The genetic evolution of Echo14 isolates was relatively active,with distant genetic relationships,showing the co⁃circulation epidemic characteristic.