宁夏地区2008年柯萨奇病毒A组16型VP1区基因特征分析

Genetic characterization of coxsackievirus A16 isolated in Ningxia Hui Municipality in 2008

目的 研究宁夏地区2008年引起手足口病（HFMD）暴发的柯萨奇病毒A组16型（CVA16）的基因特征.方法 对宁夏地区2008年HFMD患者临床标本中分离到的CVA16,采用反转录-聚合酶链反应（RT-PCR）进行VP1编码区基因扩增,对扩增产物进行核苷酸序列测定和分析.根据VP1区核苷酸序列与国内其他省份以及国际报道的CVA16株序列（来源于基因库）构建基因亲缘关系树.结果 共分离到70株CVA16,其在VP1区核苷酸和氨基酸同源性分别为90.8%～100.0%和98.9%～100.0%.亲缘进化树显示全部CVA16株可分为A和B两个基因型,B基因型又可分为B1和B2两个基因亚型.宁夏地区CVA16全部属于B1基因亚型,同时包含B1a和B1b两条进化分支,提示存在两大传播链.结论 宁夏地区分离的CVA16株与国内其他地区CVA16株类似,有B1a和B1b两个进化分支在共同循环,且与周边国家和地区流行的CVA16在基因亲缘关系和流行时间关系上都很接近,存在共同进化和循环.

Objective To study the genetic characterization of coxsackievirus A16 （CVA16）strains isolated during an epidemic of hand, foot, and mouth disease （HFMD） in Ningxia Hui Municipality in 2008. Methods Clinical samples were collected from HFMD patients in Ningxia Hui Municipality and CVA16 strains were isolated by viral isolation methods. Reverse transcriptionpolymerase chain reactions （RT-PCR）, specific for CVA16 were performed with these CVA16 strains.Entire VP1 coding region amplification and sequencing were then performed and finally phylogenetic tree was constructed among Ningxia CVA16 strains and CVA16 representative strains of known genotypes and subgenotypes. Results 70 Ningxia CVA16 strains were isolated from HFMD patients in Ningxia in 2008 and the homology of nucleotide and amino acid were 90.8%-100.0% and 98.9%-100.0%, respectively. Phylogenetic characteristics of the strains reconfirmed that they could be divided into two distinct genotypes-A and B. Genotype B could be further divided into the subgenotypes B1 and B2, while all the 70 Ningxia CVA16 strains belonged to the co-circulated clusters B1a and Blb within subgenotype B1, which belonged to 2 viral transmission chains.Conclusion Our results indicated that subgenotype B1 CVA16 strains continued to circulate over a wide geographic area of China's Mainland since the first reported episode in Shenzhen city in 1999. Like other CVA16 strains isolated elsewhere in China, both Bla and Blb evolution branches were co-circulating in Ningxia Hui Municipality. Based on the close phylgenetic and chronological relationship with CVA16 isolated in other countries and regions near China. Our data confimed that these strains co-evolved and co-circulated with those from neighboring countries and regions.