福建省1例不明原因肺炎病例中甲型H1N1流感病毒的全基因组特征分析

Complete genome analysis of influenza A(H1N1)pdm09 virus isolated from one case of pneumonia of unknown etiology(PUE)in Fujian Province,China

目的了解1例不明原因肺炎病例中甲型H1N1流感病毒的生物学特性和变异情况,为临床治疗与疫情防控提供依据。方法利用MDCK细胞分离不明原因肺炎病例中的甲型H1N1流感病毒,分离的毒株经全基因组测序后分析其抗原性、致病性和耐药性等特征。结果从该病例的咽拭子标本中分离得到1株甲型H1N1流感病毒并命名为A/FujianGulou/SWL64/2016(H1N1),其8个节段的核苷酸和氨基酸序列与A/California/07/2009(H1N1)疫苗株的相似性分别为96.9%~98.9%和96.7%~99.5%。氨基酸序列分析显示HA蛋白共有18个位点发生突变,其中K163Q、S185T、S203T和D222N变异涉及到3个不同的抗原位点,提示病毒发生抗原漂移;与受体结合位点相关的D222N突变还提示病毒感染下呼吸道的能力增强。耐药性分析显示该病毒对金刚烷胺耐药,对达菲仍然敏感。结论本次研究的甲型H1N1流感病毒具有抗原漂移现象,且具备引发重症肺炎的分子特征,应进一步加强监测,为疫情防控奠定基础。

To study the biological characteristics and mutations of influenza A（H1N1）pdm09virus isolated from one case of pneumonia of unknown etiology（PUE）,which would provide references for clinical treatment and disease control,the throat swab specimen from the PUE case was isolated in the Madin-Darby Canine Kidney（MDCK）cells,and then the antigenicity,pathogenicity and drug resistance of influenza A（H1N1）pdm09virus were analyzed after sequencing.As a result,one influenza virus strain was isolated from the specimen and named as A/FujianGulou/SWL64/2016（H1N1）.The similarities of nucleotide sequences and amino acids sequences compared with the vaccine strain A/California/07/2009（H1N1）were 96.9%-98.9% and 96.7%-99.5%,respectively.Eighteen amino acids had mutated in the HA and 4 mutations,K163 Q,S185T,S203 Tand D222N,were involved in 3different epitopes,which indicated that the antigenic drift had occurred in the influenza virus.The D222 N mutation associated with receptor binding site made the virus infect lower respiratory tract more easily.The virus was still amantadine-resistance and oseltamivir-sensitive.In conclusion,the influenza A（H1N1）pdm09virus in this study have occurred antigenic drift and has the molecular characterization of causing severe pneumonia,so further surveillance should be performed to prevent and control the influenza epidemic.