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目的分析口岸输入性甲型H1N1流感病毒的M、NP和PB1基因进化特征,及时发现变异株。方法对广东口岸2009-2011年检测的甲型H1N1流感阳性病例进行M、NP和PB1基因的RT-PCR扩增和核苷酸序列测定。以2009年甲型H1N1流感代表株A/California/04/2009/H1N1的M、NP和PB1基因作为参考序列,分析输入性病例的系统进化树、核苷酸及氨基酸序列同源性和变异位点。结果 M基因系统进化树分为4个分支,2009年病毒与2010年病毒主要分布在第Ⅰ分支,2011年检出的多数病毒聚集于第Ⅳ分支。同源性结果显示M基因高度保守,仅有5个核苷酸位点发生显著变异,对应的蛋白序列仅在氨基酸V80I位点出现突变。所有病毒NP蛋白均出现V100I突变,同时零星出现K452R突变。PB1蛋白氨基酸序列在G154D、I397M和I435T等位点发生较明显突变。结论 2009-2011年输入性甲型H1N1流感病毒M、NP、PB1基因已发生一定程度的变异,对口岸和国内流感防控提供了重要的理论依据。
Objective To analyze the evolutionary characteristics of M, NP and PB1 genes of imported H1N1 influenza virus in port and discover the mutants in time. Methods RT-PCR and nucleotide sequencing of M, NP and PB1 genes were detected in positive cases of influenza A (H1N1) from 2009 to 2011 in Guangdong port. The phylogenetic tree, nucleotide and amino acid sequence homology and variation of input sequences were analyzed with M, NP and PB1 genes of 2009 H1N1 influenza A / California / 04/2009 / H1N1 as reference sequences point. Results The phylogenetic tree of M gene was divided into four branches. In 2009, the virus and the virus in 2010 were mainly distributed in the first branch. Most of the viruses detected in 2011 gathered in the fourth branch. Homology showed that the M gene was highly conserved. Only 5 nucleotide sites were significantly mutated, and the corresponding protein sequence was only mutated at the V80I site of amino acid. V100I mutation was observed in all NP proteins, while K452R mutation appeared sporadically. The amino acid sequence of PB1 protein was more obviously mutated at G154D, I397M and I435T sites. Conclusion The M, NP and PB1 genes of imported influenza A (H1N1) virus have been mutated to some extent from 2009 to 2011, which provides an important theoretical basis for the prevention and control of influenza in ports and inland.