Ottmann Michèle, Duchamp Maude Bouscambert, Casalegno Jean-Sébastien, Frobert Emilie, Moulès Vincent, Ferraris Olivier, Valette Martine, Escuret Vanessa, Lina Bruno
Université de Lyon, France.
Antivir Ther. 2010;15(5):721-6. doi: 10.3851/IMP1576.
With the recent emergence of the novel A(H1N1) virus in 2009, the efficacy of available drugs, such as neuraminidase (NA) inhibitors, is of great concern for good patient care. Influenza viruses are known to be able to acquire resistance. In 2007, A(H1N1) viruses related to A/Brisbane/59/2007 (H1N1) (A[H1N1] Brisbane-like virus), which are naturally resistant to oseltamivir, emerged. Resistance to oseltamivir can be acquired either by spontaneous mutation in the NA (H275Y in N1), or by reassortment with a mutated NA. It is therefore crucial to determine the risk of pandemic A(H1N1) 2009 virus acquiring resistance against oseltamivir by reassortment.
We estimated the capacity of reassortment between the A(H1N1) 2009 virus and an oseltamivir-resistant A(H1N1) Brisbane-like virus by in vitro coinfections of influenza-permissive cells. The screening and the analysis of reassortant viruses was performed by specific reverse transcriptase PCRs and by sequencing.
Out of 50 analysed reassortant viruses, two harboured the haemagglutinin (HA) segment from the pandemic A(H1N1) 2009 virus and the mutated NA originated from the A(H1N1) Brisbane-like virus. The replicating capacities of these viruses were measured, showing no difference as compared to the two parental strains, suggesting that acquisition of the mutated NA segment did not impair viral fitness in vitro.
Our results suggest that the novel A(H1N1) 2009 virus can acquire by in vitro genetic reassortment the H275Y mutated NA segment conferring resistance to oseltamivir.
随着2009年新型甲型H1N1流感病毒的出现，诸如神经氨酸酶（NA）抑制剂等现有药物的疗效成为保障患者良好治疗效果的重大关注点。已知流感病毒能够产生耐药性。2007年，出现了与A/布里斯班/59/2007（H1N1）（A[H1N1]布里斯班样病毒）相关的甲型H1N1流感病毒，这些病毒对奥司他韦天然耐药。对奥司他韦的耐药性可通过NA中的自发突变（N1中的H275Y）或与突变的NA进行重配获得。因此，确定2009年甲型H1N1流感大流行病毒通过重配获得对奥司他韦耐药性的风险至关重要。
我们通过对允许流感病毒感染的细胞进行体外共感染，评估了2009年甲型H1N1流感病毒与一株对奥司他韦耐药的A（H1N1）布里斯班样病毒之间的重配能力。通过特异性逆转录聚合酶链反应（PCR）和测序对重配病毒进行筛选和分析。
在分析的50株重配病毒中，有两株含有2009年甲型H1N1流感大流行病毒的血凝素（HA）片段，而突变的NA来自A（H1N1）布里斯班样病毒。对这些病毒的复制能力进行了测定，结果显示与两个亲本毒株相比没有差异，这表明获得突变的NA片段在体外并未损害病毒的适应性。
我们的结果表明，2009年新型甲型H1N1流感病毒可通过体外基因重配获得赋予对奥司他韦耐药性的H275Y突变NA片段。
