江苏省一起胃肠炎暴发疫情中分离的诺如病毒基因特征分析

摘要

目的 分析江苏省一起胃肠炎暴发疫情中分离的诺如病毒基因特征.方法 对2016年12月16-27日江苏省一起急性胃肠炎暴发疫情中病例的肛拭子标本进行核酸提取,利用诺如病毒特异性引物对部分RNA依赖的RNA聚合酶序列及完整衣壳蛋白序列(VPl)进行RT-PCR扩增,扩增产物测序后进行基因特征分析.结果 序列比对结果显示,PCR产物在诺如病毒RNA依赖的RNA聚合酶区与GⅡ.g型别的西班牙株及芬兰株处于同一分支,同源性为98.7％,在VP1区与GⅡ.1型别的美国株同源性更高(99.4％),初步推断为重组病毒.进一步通过重组分析软件Simplot分析,其可能重组位点在VPl的5 106位点,定位在ORF1/2交叠区.VP1氨基酸变异位点分析显示,其假定的抗原表位及受体结合表位均未出现变异,仅在1 32位氨基酸位点由N突变为S.结论 江苏省胃肠炎暴发疫情中分离的诺如病毒为GⅡ.g-GⅡ.1重组变异株.%Objective To analyze the genetic characterization of norovirus isolated in an outbreak of gastroenteritis in Jiangsu province.Methods Extracted viral RNA from the swab samples of cases of acute gastroenteritis outbreak in Jiangsu province on December 16-27,2016 was reversely transcribed to cDNA,and partial RNA-dependent RNA polymerase sequence and complete capsid sequence (VP1) were amplified by RT-PCR.Amplification products were sequenced for the analysis of genetic characteristics.Results Based on sequence alignment,the variant shared a high level of identity with the strain G Ⅱ.g isolated in Spain and Finland (98.7％) in the RNA-dependent RNA polymerase region,and with the strain G Ⅱ.1 isolated in American (99.4％) in the VP1.The recombination was determined by using software Simplot,and the breakpoint of recombination was located in the ORF 1/2 overlap region at position 5 106 of VP 1.The result of amino acids alignment in capsid region showed that there were no mutations in the amino acids of the predicted epitopes and receptor binding site Ⅰ-Ⅲ,but a unique amino acid change was detected at position 132 (N-S).Conclusion The norovirus isolated in the outbreak of gastroenteritis in Jiangsu province was a rare recombinant norovirus variant G Ⅱ.g-G Ⅱ.1.