海南省2019—2020监测年度A (H1N1) pdm09流感病毒基质蛋白基因特性分析

目的 分析2019—2020监测年度（2019年4月1日—2020年3月29日）海南省A (H1N1) pdm09亚型流感病毒基质蛋白基因（Matrix, M）进化规律和M2蛋白氨基酸位点变异情况。方法 选取14株2019—2020年海南省分离的A (H1N1) pdm09亚型流感病毒进行基因序列测定,采用Neighbor-Joining方法进行种系进化分析,通过系统进化树比较海南流行株与疫苗株的差异。测序结果用MEGA 10.1.8和DNASTAR7.0.1软件进行基因特性分析及基因同源性分析。结果 2019—2020监测年度,海南省A (H1N1) pdm09亚型流感病毒分离株占分离株的4.9%。序列分析显示,海南省A (H1N1) pdm09亚型流感病毒与国际疫苗株A/Brisbane/02/2018的M基因在核苷酸系统进化树6B.1分支上,核苷酸与氨基酸同源性范围为98.7%~100.0%、98.8%~100.0%。12株分离株胞外区编码区S23N氨基酸发生变异;跨膜区14株分离株均发生S31N位点突变,突变率为100.0%;1株I39V位点氨基酸变异;9株分离株在胞浆区E70D位氨基酸位点发生变异。结论 2019—2020监测年度海南省A (H1N1) pdm09亚型流感病毒活动水平较低,与疫苗株相匹配,对金刚烷胺类药物耐药,应特别关注M2蛋白氨基酸变异情况,为临床抗流感病毒药物的使用提供科学依据。

M gene characteristics of influenza A (H1N1) pdm09 viruses from Hainan province during the 2019-2020 influenza season

Objective s To analyze the evolution pattern of matrix (M) gene and amino acid site variation of M2 protein of influenza A (H1N1) pdm09 viruses in Hainnan province during the influenza epidemic season 2019-2020 (April 1, 2019 - March 29, 2020). Methods A total of 14 strains of influenza A (H1N1) pdm09 subtype virus was selected for sequencing. The phylogenetic trees were constructed by neighbor-jointing method, and the differences between the prevalent and vaccine strains in Hainan were compared by gene evolutionary trees. The sequencing results were analyzed by MEGA 10.1.8 and DNASTAR 7.0.1 software. Results During 2019-2020 influenza season influenza A (H1N1) pdm09 virus accounted for 4.9% of total influenza viruses detected in Hainan province. Phylogenetic analysis showed that M gene of influenza A (H1N1) pdm09 virus isolates in Hainan province from 2019 to 2020 could be divide into 6B.1 clade, be same with the international vaccine strain A/Brisbane/02/2018. The nucleotide and amino acid similarities were 98.7%-100.0%, 98.8%-100.0% respectively. And 12 isolates had mutations in amino acid S23N in the coding region of the extracellular region of the protein; all 14 isolates had mutations in the S31N site in the transmembrane region, and the mutation rate was 100.0%. There was 1 isolate with amino acid variation at the I39V locus and 9 isolates with amino acid variation at the E70D locus in the cytoplasmic region. Conclusions These data suggest that the activity of influenza A (H1N1) pdm09 virus was low level in Hainan province during 2019-2020 influenza season. The strains isolated in Hainan province have remained resistant to amantadine, and the circulating viruses were matched by current influenza vaccine. Special attention should be paid to the amino acid variation of M2 protein in future work to provide a scientific basis for the use of clinical anti-influenza virus drugs.