2014-2016年天津市致病毒性脑炎人类肠道病毒基因特征分析

The genetic characteristics of human enteroviruses causing viral encephalitis in Tianjin from 2014-2016

目的了解天津市引起病毒性脑炎的人类肠道病毒(HEV)构成及其基因特征。方法收集2014-2016年天津市病毒性脑炎患者脑脊液和血清标本,通过细胞培养法分离病毒,采用RT-PCR分段扩增HEV VP1区全长序列并测序,进行同源性分析和基于VP1完整编码区的系统进化分析。结果从82份HEV阳性标本中分离到13株HEVB病毒,分离率15.85%,其中8株CV-B5型,2株E-6型,CV-B3型、E-18型、E-30型各1株。系统进化分析,天津市8株CV-B5与国内流行株C基因型亲缘关系较近,且分为两个不同的分支;HEV-B其它血清型均与国内流行株亲缘关系较近。结论天津市致病毒性脑炎HEV病原谱呈多样性特点,其中CV-B5为优势病原体,属于C基因型,且可能存在两条不同的传播链。

Objective To study the spectrum of human enteroviruses（HEV）causing viral encephalitis in Tianjin and their genetic characteristics. Methods Cerebrospinal fluid and serum samples were collected from patients with viral encephalitis in Tianjin from 2014-2016.Real-time RT-PCR was used to screen for HEV.Viruses were isolated via cell culture.The whole VP1 gene was then subjected to RT-PCR amplification,sequencing,homogeneity and phylogenetic tree analysis. Results Thirteen HEV-B strains were isolated from 82 samples at a rate of 15.85%.Eight of the isolates were CV-B5 strains,2 were E-6,1 was CV-B3,1 was E-18,and 1 was E-30.Phylogenetic tree analysis indicated that the genetic traits of the 8 CV-B5 strains isolated from Tianjin,which can be divided into two clusters,were close to those of genotype C strains in China.The two E-6 strains isolated from Tianjin were genotype D.The CV-B3 strains were genotype E,the E-18 strain was genotype C,and the E-30 strain was genotype II.All of the Tianjin HEV-B strains occupied the same clusters as the prevalent strains in China. Conclusion A vast spectrum of pathogens has caused viral encephalitis in Tianjin,and CV-B5 is the most prevalent of those pathogens.All of the CV-B5 strains from Tianjin were genotype C and may have two different chains of transmission.