Department of Viroscience, Erasmus Medical Center, Rotterdam, 3015GE, the Netherlands.
Clinical Virology and Diagnostics, 1817HL, Alkmaar, the Netherlands.
Antiviral Res. 2021 May;189:105060. doi: 10.1016/j.antiviral.2021.105060. Epub 2021 Mar 10.
Amino acid substitutions in influenza virus neuraminidase (NA) that cause resistance to neuraminidase inhibitors (NAI) generally result in virus attenuation. However, influenza viruses may acquire secondary substitutions in the NA and hemagglutinin (HA) proteins that can restore viral fitness. To assess to which extent this happens, the emergence of NAI resistance substitutions and secondary - potentially compensatory - substitutions was quantified in influenza viruses of immunocompetent individuals included in the Influenza Resistance Information Study (IRIS; NCT00884117). Known resistance substitutions were detected by mutation specific RT-PCR in viruses of 57 of 1803 (3.2%) oseltamivir-treated individuals, including 39 individuals infected with A/H1N1pdm09 [H275Y] virus and 18 with A/H3N2 [R292K] virus. A total of fifteen and ten other amino acid substitutions were acquired in HA and NA respectively, of A/H1N1pdm09, A/H3N2 and influenza B viruses upon treatment with oseltamivir but none of these was associated with resistance to oseltamivir. All cultured viruses with the known resistance substitutions H275Y or R292K showed reduced susceptibility to oseltamivir in the NA-star assay. Upon next-generation sequencing, the vast majority of NAI resistant A/H1N1pdm09 and A/H3N2 viruses had no resistance-associated secondary substitutions at high frequency. Only in two A/H1N1pdm09 [H275Y] viruses, the potentially compensatory secondary substitutions HA-D52N and NA-R152K were detected. We conclude that the emergence of secondary substitutions that may restore viral fitness upon the emergence of known influenza virus NAI resistance substitutions was a rare event in this immunocompetent population.
流感病毒神经氨酸酶（NA）中的氨基酸取代通常会导致对神经氨酸酶抑制剂（NAI）的耐药性，但流感病毒可能会在 NA 和血凝素（HA）蛋白中获得次要取代，从而恢复病毒适应性。为了评估这种情况发生的程度，在免疫功能正常的个体中包含的流感病毒中量化了 NAI 耐药性取代和次要 - 潜在补偿性 - 取代的出现，这些个体包括在流感耐药信息研究（IRIS；NCT00884117）中。通过突变特异性 RT-PCR 在 1803 名奥司他韦治疗个体的 57 名个体的病毒中检测到已知的耐药性取代，其中包括 39 名感染 A/H1N1pdm09 [H275Y]病毒和 18 名感染 A/H3N2 [R292K]病毒。在奥司他韦治疗后，A/H1N1pdm09、A/H3N2 和 B 型流感病毒的 HA 和 NA 中分别获得了总共 15 个和 10 个其他氨基酸取代，但这些取代均与奥司他韦耐药性无关。具有已知耐药性取代 H275Y 或 R292K 的所有培养病毒在 NA 星测定中对奥司他韦的敏感性降低。在下一代测序中，绝大多数 NAI 耐药性 A/H1N1pdm09 和 A/H3N2 病毒在高频下没有耐药相关的次要取代。仅在两种 A/H1N1pdm09 [H275Y]病毒中，检测到潜在的补偿性次要取代 HA-D52N 和 NA-R152K。我们的结论是，在免疫功能正常的人群中，在出现已知流感病毒 NAI 耐药性取代后，可能恢复病毒适应性的次要取代的出现是一个罕见事件。
