北京地区37例流感患者的病毒遗传变异及耐药突变分析

Genetic variation and drug resistance mutation of influenza virus during 2013-2014 in Beijing, China: a report of 37 cases

目的分析2013-2014年度北京地区A型H1N1、H3N2和B型流感病毒神经氨酸酶(NA)基因的遗传变异情况,以及流感病毒对金刚烷胺类和NA抑制剂类(NAIs)抗病毒药物的耐药变异情况。方法从37例流感病毒感染患者的鼻/咽拭子样本中提取RNA,采用荧光定量PCR检测流感病毒的基因型/亚型;反转录PCR方法扩增A型流感病毒的NA和基质蛋白M2(M2)基因片段及B型流感病毒的NA和血凝素(HA)基因片段,直接DNA测序。采用Mega软件构建系统进化树分析病毒的演变情况,Vector NTI软件分析耐药变异情况。结果 37例患者中共检出A型流感病毒29例,其中H1N1 23例,H3N2 6例;B型流感病毒8例。所有A型流感病毒均发生M2基因S31N金刚烷胺类药物耐药位点变异。A型和B型流感病毒均未发现NAIs耐药位点变异。系统进化分析显示,B型流感病毒有5例样品NA基因和HA基因分型不一致,NA基因均为B-Victoria系,而HA基因为B-Yamagata系。结论北京地区人群A型流感病毒均对金刚烷胺类药物耐药,但A型和B型病毒均未检测出NAIs耐药变异。B型流感病毒流行株中存在B-Yamagata系和B-Victoria系重组病毒株。

Objective To evaluate the evolutionary characteristics of H1N1 and H3N2 influenza A and B viruses, and investigate the drug-resistant mutation of influenza viruses to amantadine and neuraminidase inhibitors（NAIs） during 2013-2014 episode in Beijing. Methods RNA was extracted from pharyngeal or nasal swab samples from 37 influenza virus-infected patients and viral genotype/subgenotype were analyzed by real-time reverse-transcription polymerase chain reaction. All influenza A viruses were further directly sequenced for NA and M2 matrix protein（M2） genes, and all influenza B viruses were further sequenced for NA and hemagglutinin（HA） genes. The drug-resistant mutations and genetic evolution were analyzed by Vector NTI software and phylogenetic trees were plotted using Mega software. Results Influenza A viruses were identified in 29 patients, including 23 with H1N1 and 6 with H3N2 viruses. Influenza B viruses were identified in 8 patients. M2 gene of all 29 patients with influenza A virus infection were detected with S31 N amantadine-resistant mutation. NAIs-resistant mutations were not detected in all 37 patients with influenza A and B virus infection. Phylogenetic analysis showed that HA genes from 5 influenza B virus strains were identified as the B-Yamagata lineage, while NA genes from the corresponding strains were identified as B-Victoria lineage. Conclusions Among Beijing Influenza B virus strains reassortants derived from B-Yamagata lineage and B-Victoria lineage were found.