深圳市H7N9禽流感病毒神经氨酸酶基因演化分析

Evolutionary analysis of neuraminidase gene of H7N9 influenza viruses isolated in Shenzhen

目的掌握深圳市从禽类市场外环境及人感病例中分离到的H7N9禽流感病毒神经氨酸酶(NA)基因的演化,以及病毒对神经氨酸酶抑制剂(NAI)的耐药情况,为人感染H7N9病例的临床救治方案提供参考。方法将深圳市11份人感染H7N9禽流感病例鼻咽拭子标本以及3份活禽市场的环境拭子样本,经分离培养后对其NA片段进行全长测序。并选取国内外的H7N9病毒株序列作为参考,运用Mega软件进行种系发生树的构建、耐药相关位点及糖基化位点的分析。结果对NA片段的序列分析发现,所有深圳株NA基因的蛋白抗原位点和糖基化位点都相对保守,并且未出现R294K耐药位点。但发现三株未出现H7N9特征性蛋白柄部氨基酸的缺失株。结论深圳市分离到的H7N9病毒株与中国其它省份的流行株高度同源,对NAI仍然敏感。蛋白柄部氨基酸变异提示还需要对其进行进一步的研究和监测。

Objective To analyze the evolution of neuraminidase gene of H7N9 influenza viruses isolated in Shenzhen,and surveil the neuraminidase inhibitor resistance of these viruses. Methods A total of 14 viruses isolated from H7N9 infected patients and environment. The NA genes of these isolates were sequenced. Phylogenetic analysis of the sequences was performed with Megasoftware. Results With the high conservation of glycosylation sites and antigenic site in NA protein, non-mutation of R294 K was found in all 14 H7N9 strains in Shenzhen. But it is notable that 3 strains didn＇t show the amino acid delete in the petiole of the NA protein, which was regarded as the character of this novel H7N9 strain. Conclusion H7N9 virus isolated in Shenzhen had high homology with other epidemic strains in China. All Shenzhen strains were sensitive to the NAI. However, close monitoringand understanding of the H7N9 avianinfluenza virus shouldbe a priorityin the future.