title: The E119D neuraminidase mutation identified in a multidrug-resistant influenza A(H1N1)pdm09 isolate severely alters viral fitness in vitro and in animal models.
abstract: We recently isolated an influenza A(H1N1)pdm09 E119D/H275Y neuraminidase (NA) variant from an immunocompromised patient who received oseltamivir and zanamivir therapies. This variant demonstrated cross resistance to zanamivir, oseltamivir, peramivir and laninamivir. In this study, the viral fitness of the recombinant wild-type (WT), E119D and E119D/H275Y A(H1N1)pdm09 viruses was evaluated in vitro and in experimentally-infected C57BL/6 mice and guinea pigs. In replication kinetics experiments, viral titers obtained with the E119D and E119D/H275Y recombinants were up to 2- and 4-log lower compared to the WT virus in MDCK and ST6GalI-MDCK cells, respectively. Enzymatic studies revealed that the E119D mutation significantly decreased the surface NA activity. In experimentally-infected mice, a 50% mortality rate was recorded in the group infected with the WT recombinant virus whereas no mortality was observed in the E119D and E119D/H275Y groups. Mean lung viral titers on day 5 post-inoculation for the WT (1.2 ± 0.57 × 10(8) PFU/ml) were significantly higher than those of the E119D (9.75 ± 0.41 × 10(5) PFU/ml, P < 0.01) and the E119D/H275Y (1.47 ± 0.61 × 10(6) PFU/ml, P < 0.01) groups. In guinea pigs, comparable seroconversion rates and viral titers in nasal washes (NW) were obtained for the WT and mutant index and contact groups. However, the D119E reversion was observed in most NW samples of the E119D and E119D/H275Y animals. In conclusion, the E119D NA mutation that could emerge in A(H1N1)pdm09 viruses during zanamivir therapy has a significant impact on viral fitness and such mutant is unlikely to be highly transmissible.
authors.affiliation: CHUQ-CHUL and Laval University, Québec City, Québec, Canada.
authors.forename: Yacine
authors.initials: Y
authors.lastname: Abed
authors.affiliation: CHUQ-CHUL and Laval University, Québec City, Québec, Canada.
authors.forename: Xavier
authors.initials: X
authors.lastname: Bouhy
authors.affiliation: Laboratory of Virology, University of Geneva Hospitals, Geneva, Switzerland.
authors.forename: Arnaud G
authors.initials: AG
authors.lastname: L'Huillier
authors.affiliation: CHUQ-CHUL and Laval University, Québec City, Québec, Canada.
authors.forename: Chantal
authors.initials: C
authors.lastname: Rhéaume
authors.affiliation: CHUQ-CHUL and Laval University, Québec City, Québec, Canada.
authors.forename: Andrés
authors.initials: A
authors.lastname: Pizzorno
authors.affiliation: CHUQ-CHUL and Laval University, Québec City, Québec, Canada.
authors.forename: Miguel
authors.initials: M
authors.lastname: Retamal
authors.affiliation: CHUQ-CHUL and Laval University, Québec City, Québec, Canada.
authors.forename: Clément
authors.initials: C
authors.lastname: Fage
authors.affiliation: GSK Vaccines, Laval, QC, Canada.
authors.forename: Karen
authors.initials: K
authors.lastname: Dubé
authors.affiliation: GSK Vaccines, Laval, QC, Canada.
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Joly
authors.affiliation: GSK Vaccines, Laval, QC, Canada.
authors.forename: Edith
authors.initials: E
authors.lastname: Beaulieu
authors.affiliation: GSK Vaccines, Laval, QC, Canada.
authors.forename: Corey
authors.initials: C
authors.lastname: Mallett
authors.affiliation: Laboratory of Virology, University of Geneva Hospitals, Geneva, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Kaiser
authors.affiliation: CHUQ-CHUL and Laval University, Québec City, Québec, Canada. Electronic address: Guy.Boivin@crchul.ulaval.ca.
authors.forename: Guy
authors.initials: G
authors.lastname: Boivin
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D003062:Codon; D024882:Drug Resistance, Viral; D056084:Genetic Fitness; D006168:Guinea Pigs; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000502:physiology*; D051379:Mice; D009154:Mutation; D009439:Neuraminidase / Q000235:genetics*; D009976:Orthomyxoviridae Infections / Q000821:virology*; D011995:Recombination, Genetic; D019562:Viral Load; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D000998:Antiviral Agents; D003062:Codon; D014764:Viral Proteins; C487630:NA protein, influenza A virus; D009439:Neuraminidase
keywords: A(H1N1)pdm09; E119D; Influenza; Neuraminidase; Resistance; Zanamivir