2009年泉州市H1N1流感监测及基因特性分析

Influenza H1N1 surveillance and analysis of genetic characteristics of predominant strains in Quanzhou during 2009

目的 了解2009年泉州地区H1N1流感监测情况,分析泉州市H1N1流感病毒的HA和NA基因特征,探讨该病毒的遗传变异及分子特性.方法 对泉州市H1N1流感监测期间的病人咽拭子采用real-time RT-PCR方法检测病毒核酸,MDCK细胞培养进行病毒分离、鉴定,并提取其中2株代表性毒株病毒RNA 采用RT-PCR扩增病毒HA和NA基因,纯化产物进行核苷酸序列测定 用DNAStar Megalign软件进行序列分析.结果 1020份咽拭子中有200份为H1N1流感病毒核酸阳性,70份季节性流感病毒核酸阳性,其中53份为H3N2亚型,14份为H1N1亚型,3份为B型,并分离到29株甲型H1N1流感病毒株.HA基因经核苷酸序列测定显示,该毒株与北美流行株高度同源,由HA基因核苷酸序列推导的氨基酸系列与疫苗株A/Brisbane/59/2007相比,有22个位于抗原决定簇的氨基酸位点发生变异,但受体结合特异性仍为人样受体.NA基因耐药性位点分析,显示对达菲药物依然敏感.结论 2009年泉州市H1N1流感流行毒株与北美流行株高度同源,相对于疫苗代表株出现了HA蛋白抗原性的改变.

Objective To investigate the influenza H1N1 virus surveillance of 2009 in Quanzhou,and analyze the HA and NA gene of influenza H1N1 virus, explore its genetic variation and molecular characteristics. Methods During the influenza H1N1 virus surveillance in Quanzhou,specimens of throat swabs from the patients with influenza were collected, and detected by real-time RT-PCR. Viruses were isolated with MDCK cells and identified with serological test. Two influenza virus isolates were extracted, and their HA and NA genes were amplified by RT-PCR. The purified PCR products were sequenced. The data obtained were analyzed with the software DNAMAN. Results Of 1020, influenza H1N1 virus RNA was detected in 200 specimens, seasonal influenza virus RNA was detected in 70 specimens. A total of 29 influenza A H1N1 virus strains were isolated. The nucleotide homology in the HA gene was highly homologous with that of pandemic influenza virus in North America. The amino acids sequences deduced from the nucleotide sequences in HA region of the isolated strain had 22 variations compared with A/Brisbane/59/2007 vaccine strain recommend by WHO,the characteristics of α2,6 sialic acid receptor binding remained. The analysis of amino acids sequences of NA indicated that this virus possessed Oseltamivir sensitivity. Conclusion The causative influenza H1N1 strains in Quanzhou is highly homologous with that of pandemic influenza in North America, and it is antigenically and genetically different from the vaccine strain.