Generation and characterization of recombinant pandemic influenza A(H1N1) viruses resistant to neuraminidase inhibitors

J Infect Dis. 2011 Jan 1;203(1):25-31. doi: 10.1093/infdis/jiq010.


Background: Neuraminidase inhibitors (NAIs) play a key role in the management of influenza epidemics and pandemics. Given the novel pandemic influenza A(H1N1) (pH1N1) virus and the restricted number of approved anti-influenza drugs, evaluation of potential drug-resistant variants is of high priority.

Methods: Recombinant pH1N1 viruses were generated by reverse genetics, expressing either the wild-type or any of 9 mutant neuraminidase (NA) proteins (N2 numbering: E119G, E119V, D198G, I222V, H274Y, N294S, S334N, I222V-H274Y, and H274Y-S334N). We evaluated these recombinant viruses for their resistance phenotype to 4 NAIs (oseltamivir, zanamivir, peramivir, and A-315675), NA enzymatic activity, and replicative capacity.

Results: The E119G and E119V mutations conferred a multidrug resistance phenotype to many NAIs but severely compromised viral fitness. The oseltamivir- and peramivir-resistance phenotype was confirmed for the H274Y and N294S mutants, although both viruses remained susceptible to zanamivir. Remarkably, the I222V mutation had a synergistic effect on the oseltamivir- and peramivir-resistance phenotype of H274Y and compensated for reduced viral fitness, raising concerns about the potential emergence and dissemination of this double-mutant virus.

Conclusions: This study highlights the importance of continuous monitoring of antiviral drug resistance in clinical samples as well as the need to develop new agents and combination strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution / genetics
  • Antiviral Agents / pharmacology*
  • Cyclopentanes / pharmacology
  • Drug Resistance, Viral*
  • Guanidines / pharmacology
  • Humans
  • Influenza A Virus, H1N1 Subtype / drug effects*
  • Influenza A Virus, H1N1 Subtype / genetics
  • Influenza A Virus, H1N1 Subtype / isolation & purification
  • Influenza A Virus, H1N1 Subtype / physiology
  • Influenza, Human / virology
  • Microbial Sensitivity Tests
  • Mutation, Missense
  • Neuraminidase / antagonists & inhibitors*
  • Neuraminidase / genetics
  • Oseltamivir / pharmacology
  • Pyrrolidines / pharmacology
  • Recombination, Genetic*
  • Viral Plaque Assay
  • Viral Proteins / genetics*
  • Virus Replication / drug effects
  • Zanamivir / pharmacology


  • A 315675
  • Antiviral Agents
  • Cyclopentanes
  • Guanidines
  • Pyrrolidines
  • Viral Proteins
  • Oseltamivir
  • NA protein, influenza A virus
  • Neuraminidase
  • Zanamivir
  • peramivir