北京地区诺如病毒分子生物学特点初步研究

A preliminary study on molecular characteristics of noroviruses detected in Beijing

目的了解北京地区诺如病毒的分子生物学特点。方法收集北京市2007年1-3月非细菌性胃肠炎暴发和散发病例,采集患者粪便标本,使用逆转录聚合酶链反应(RT-PCR)对粪便标本进行诺如病毒RNA检测,对RT-PCR阳性标本的PCR产物进行克隆测序。结果检测38例粪便标本,共有27例阳性。随机选择其中4例PCR产物进行克隆测序,获得4株诺如病毒序列进行比对分析,结果显示,该4株病毒序列与诺如病毒GⅡ/4型参考株同源性最高,其中与荷兰和日本提交的诺如病毒GⅡ/4型变异株最为接近,同源性分别为97.8%～98.5%和95.2%～95.9%。系统发生树分析表明,该4株诺如病毒与荷兰、日本流行的GⅡ/4型变异株处于同一分支上。结论北京地区存在诺如病毒GⅡ/4型变异株流行,其与2006年荷兰和日本的诺如病毒流行株属同一类GⅡ/4型变异株。

Objective To investigate the molecular characteristics of noroviruses detected in Beijing. Methods From January to March 2007, cases from both outbreaks and sporadic episodes of acute nonbacterial gastroenteritis were investigated in Beijing, and the fecal specimens of the patients were collected. Noroviruses were detected by a reverse transcription polymerase chain reaction（RT-PCR）, and then the PCR products were cloned and sequenced. Results A total of 27 positive cases were identified as caused by noroviruses among the 38 patients with acute viral gastroenteritis, and four PCR products were randomly selected for further studies on sequencing. When comparing to the nucleotide sequences of norovirus reference strains from GenBank, the highest homology was found between the four isolates and the norovirus G Ⅱ/4 strains. The four strains isolated from Beijing were almost identical to the G Ⅱ/4 variants that causing epidemics in the Netherlands and in Japan with the homology of 97.8 %-98.5 % and 95.2 %-95.9 %, respectively. Phylogenetic analysis revealed that the four isolates were located at the same branch as the norovirus G Ⅱ/4 variants in Netherlands and Japan. Conclusion New norovirus G Ⅱ/4 variants were found in Beijing, and data from sequence analysis showed that the four isolates and the epidemic strains isolated from both the Netherlands and Japan in 2006 belonged to the same group of norovirus G Ⅱ/4.