青海省分离到肠道病毒71型及其VP1区基因特征分析

Human enterovirus 71 that firstly isolated in Qinghai province and their genetic features of VP1 region

目的 研究2008年青海省手足口病（Hand,Foot and Mouth Disease,HFMD）的致病病原体中肠道病毒71型（Human Enterovirus 71,HEV71）的VP1区基因特征.方法 采集青海省HFMD患者的粪便、疱疹液和咽拭子标本共335份,并进行病毒分离,然后对阳性分离株病毒进行肠道病毒血清型别的分子定型.对分离到的HEV71阳性分离株进行VP1编码区基因扩增,核苷酸序列测定和同源进化分析.结果 在335份临床标本中,共分离到45株阳性病毒分离物,其中30株鉴定为HEV71（占66.7%）,是主要病原体.对30株HEV71进行VP1区核苷酸序列测定后,分析发现它们在VP1区核苷酸水平和氨基酸水平上有一定差异,同源性分别在95.2%～100.0%和96.6%～100%之间.它们与1998年以来在我国分离的HEV71在核苷酸和氨基酸水平上的同源性都较高.与其他35株各基因型和基因亚型的HEV71代表株构建的亲缘进化树中显示,青海省HEY71分离株与C4亚型代表株聚为一簇,属于C4基因亚型C4a进化分支.结论 青海省从HFMD病例中分离到HEV71,也确认了青海省HFMD的病原体HEV71流行株的基因型为C4基因型中的C4a进化分支,并且存在多个传播链.

Objective To study the genetic characterizations of VP1 gene of human enterovirus 71 （ HEV71 ） isolated from clinical specimens of Hand, Foot and Mouth Disease （HFMD） patients in Qinghai Province in 2008. Methods 335 clinical samples including stools, throat swabs and vesicle fluids were collected from HFMD patients in Qinghai Province. Viral isolation was performed, and molecular typing was performed with the positive isolates. Then 30 identified HEV71 isolates were performed for entire VP1 coding region amplification and sequencing. Results Among the 355 clinical samples, 45 human enteroviruses were isolated, and among them, 30 were identified as HEV71. Then 30 HEV71 positive isolates were performed by nucleotide sequencing. It showed that there was some difference in the nucleotide and the amino acid among the 30 HEV71 strains, the homology were 95.2%-100% and 96.6%-100%,respectively. But they all closed to HEV71 strains isolated in China after 1998, and from the phylogenetic tree constructed with 30 Qinghai HEV71 strains and other 35 HEV71 strains represented all known genotype and subgenotype HEV71 strains available from GenBank, it revealed that the 30 Qinghai HEV71 strains clustered within the C4a evolution branch of C4 subgenotype. Conclusion HEV71 was isolated in HFMD patients in Qinghai province, and the HEV71 strains causing HFMD outbreaks in Qinghai province in 2008 were all belong to C4a evolution branch of C4 subgenotype with several transmission chains.