2017-2018年广州市甲型H1N1流感病毒耐药基因变异监测

目的 对广州市流感监测人群呼吸道标本进行甲型H1N1流感病毒分离和测序,并对耐药基因突变和遗传进化特征进行分析。方法 2017年1月-2018年3月,对4家流感监测医院的5831份监测标本进行甲型H1N1流感病毒核酸检测,将阳性标本接种MDCK细胞进行流感病毒分离和测序,应用DNA Star7.1软件和MEGA 4.0软件对耐药基因进行测序分析。结果 5831份监测标本中检出甲型H1N1核酸阳性标本222份,检出率为3.81%,其中分离甲型H1N1流感病毒61株,分离率为1.05%。有2株病毒分离株出现了H274Y突变,突变率为3.28%。所有病毒分离株均发生了S31N突变,突变率为100%,同时另有2株出现V27A突变,突变率为3.28%。部分2017年毒株和2018年毒株已形成于A/Michigan/45/2015疫苗株分支之外的另一独立小分支。结论 2017年广州市流感监测病例中监测到2株H1N1流感病毒分离株为奥司他韦耐药突变株,且该耐药株均位于当前疫苗株流行分支以外的独立分支,有必要对广州市甲型H1N1流感病毒进行持续监测。

Monitoring of the mutations of influenza A H1N1 virus drug-resistance gene in Guangzhou,2017-2018

Objective To isolate and sequence H1N1 influenza virus isolated from respiratory specimens of influenza surveillance population in Guangzhou,and to analyze the mutation and evolution characteristics of drug resistance genes.Methods From January 2017 to March,1818,5,831 surveillance samples from 4 influenza surveillance hospitals were tested for H1N1 influenza virus nucleic acid.Positive samples were inoculated into MDCK cells for influenza virus isolation and sequencing.DNA Star7.1 software was applied.The drug resistance gene was sequenced and analyzed with MEGA 4.0 software.Results A total of 222 H1N1 positive samples were detected in the respiratory tract specimens of 5831 influenza-like cases,with a detection rate of 3.81%.61 strains of A H1N1 influenza virus were isolated.There were 2 isolates with H274Y mutation in NA gene.All strains had S31N mutation in M2 gene.Phylogenetic analysis showed that some isolates from 2017 and 2018 were different from the A/Michigan/45/2015 branch.Conclusion In 2017,two A H1N1 influenza strains with H274Y mutation in NA gene were detected in influenza surveillance cases in Guangzhou for the first time,which belonged to other prevalent branches different from the current vaccine strains.Therefore,it is necessary to continuously monitor the mutation and evolution of the resistance genes A H1N1 influenza virus in Guangzhou.