title: Generation and characterization of recombinant pandemic influenza A(H1N1) viruses resistant to neuraminidase inhibitors.
abstract: 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.
authors.affiliation: Research Center in Infectious Diseases of the CHUQ-CHUL and Laval University, Québec City, Québec, Canada.
authors.forename: Andrés
authors.initials: A
authors.lastname: Pizzorno
authors.forename: Xavier
authors.initials: X
authors.lastname: Bouhy
authors.forename: Yacine
authors.initials: Y
authors.lastname: Abed
authors.forename: Guy
authors.initials: G
authors.lastname: Boivin
mesh_terms: D000146:Acids, Carbocyclic; D019943:Amino Acid Substitution / Q000235:genetics; D000998:Antiviral Agents / Q000494:pharmacology*; D003517:Cyclopentanes / Q000494:pharmacology; D024882:Drug Resistance, Viral; D006146:Guanidines / Q000494:pharmacology; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D007251:Influenza, Human / Q000821:virology; D008826:Microbial Sensitivity Tests; D020125:Mutation, Missense; D009439:Neuraminidase / Q000037:antagonists & inhibitors* / Q000235:genetics; D053139:Oseltamivir / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D011995:Recombination, Genetic; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000235:genetics*; D014779:Virus Replication / Q000187:drug effects; D053243:Zanamivir / Q000494:pharmacology
chemical_list: C456059:A 315675; D000146:Acids, Carbocyclic; D000998:Antiviral Agents; D003517:Cyclopentanes; D006146:Guanidines; D011759:Pyrrolidines; D014764:Viral Proteins; D053139:Oseltamivir; C487630:NA protein, influenza A virus; D009439:Neuraminidase; D053243:Zanamivir; C414210:peramivir