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目的了解长沙市2010年-2012年乙型流感病毒神经氨酸酶(NA)基因的分子流行病学特征及对神经氨酸酶抑制剂类药物的耐药情况分析,为临床诊疗和疾病预防提供一定的参考依据。方法采集长沙市流感网络监测哨点医院流感样病例咽拭子标本进行流感病毒的分离和鉴定,并对分离到的乙型流感病毒进行病毒核酸提取,一步法RTPCR扩增NA基因片段,双向测定核苷酸序列,对基因序列和氨基酸序列特征比对分析。结果 2010年-2012年分离的乙型流感毒株分属于Yamagata系和Victoria系两个谱系,谱系内毒株间NA基因距离很近。与WHO推荐疫苗株B/Brisbane/60/2008相比,NA基因的同源性在94.5%～99.5%之间。序列分析显示,所有毒株NA基因氨基酸序列无插入或缺失,酶活性中心位点高度保守,糖基化位点无变异,有报道与耐药有关的氨基酸位点如第116、152、198、222、273位氨基酸均保守无突变。结论 2010年-2012年长沙市流行的乙型流感病毒NA基因高度保守,对神经氨酸酶抑制剂类药物仍敏感。但随着国内外耐药株的不断出现,仍需加强监测。
Objective To understand the molecular epidemiological characteristics of neuraminidase (NA) gene of influenza B virus from 2010 to 2012 in Changsha City and to analyze the drug resistance of neuraminidase inhibitors for clinical diagnosis and disease prevention A certain reference. Methods Influenza virus was isolated and identified from the throat swab samples of influenza-like cases in the sentinel hospital of Changsha City Influenza Surveillance Hospital. The virus nucleic acid was extracted from the isolated influenza B virus. The NA gene fragment was amplified by one-step RTPCR. Nucleotide sequence, gene sequence and amino acid sequence alignment analysis. Results The strains of influenza B isolated from 2010 to 2012 belonged to two genera of Yamagata line and Victoria line, and the NA gene in the lineage was very close. Compared with the WHO recommended vaccine strain B / Brisbane / 60/2008, the NA gene homology is between 94.5% and 99.5%. Sequence analysis showed that there was no insertion or deletion of amino acid sequence of NA gene in all strains, the enzyme activity was highly conserved at the central site and no mutation was observed at the glycosylation site. Some amino acid residues related to drug resistance such as Nos. 116, 152, 198, The amino acids 222 and 273 are all conserved without mutation. Conclusion The NA gene of influenza B virus circulating in Changsha City from 2010 to 2012 is highly conservative and sensitive to neuraminidase inhibitors. However, with the continuous emergence of drug-resistant strains both at home and abroad, monitoring still needs to be strengthened.