title: E119D Neuraminidase Mutation Conferring Pan-Resistance to Neuraminidase Inhibitors in an A(H1N1)pdm09 Isolate From a Stem-Cell Transplant Recipient.
abstract: BACKGROUND
  An influenza A(H1N1)pdm09 infection was diagnosed in a hematopoietic stem cell transplant recipient during conditioning regimen. He was treated with oral oseltamivir, later combined with intravenous zanamivir. The H275Y neuraminidase (NA) mutation was first detected, and an E119D NA mutation was identified during zanamivir therapy.
  
  
  METHODS
  Recombinant wild-type (WT) E119D and E119D/H275Y A(H1N1)pdm09 NA variants were generated by reverse genetics. Susceptibility to NA inhibitors (NAIs) was evaluated with a fluorometric assay using the 2'-(4-methylumbelliferyl)-α-D-N-acetylneuraminic acid (MUNANA) substrate. Susceptibility to favipiravir (T-705) was assessed using plaque reduction assays. The NA affinity and velocity values were determined with NA enzymatic studies.
  
  
  RESULTS
  We identified an influenza A(H1N1)pdm09 E119D mutant that exhibited a marked increase in the 50% inhibitory concentrations against all tested NAIs (827-, 25-, 286-, and 702-fold for zanamivir, oseltamivir, peramivir, and laninamivir, respectively). The double E119D/H275Y mutation further increased oseltamivir and peramivir 50% inhibitory concentrations by 790- and >5000-fold, respectively, compared with the WT. The mutant viruses remained susceptible to favipiravir. The NA affinity and velocity values of the E119D variant decreased by 8.1-fold and 4.5-fold, respectively, compared with the WT.
  
  
  CONCLUSIONS
  The actual emergence of a single NA mutation conferring pan-NAI resistance in the clinical setting reinforces the pressing need to develop new anti-influenza strategies.
authors.affiliation: Laboratory of Virology, Divisions of Infectious Diseases and Laboratory Medicine.
authors.forename: Arnaud G
authors.initials: AG
authors.lastname: L'Huillier
authors.affiliation: Centre Hospitalier Universitaire de Québec and Université Laval, Quebec City, Canada.
authors.forename: Yacine
authors.initials: Y
authors.lastname: Abed
authors.affiliation: Department of Genetic Medicine and Development, University of Geneva Medical School Swiss Institute of Bioinformatics, University of Geneva, Switzerland.
authors.forename: Tom J
authors.initials: TJ
authors.lastname: Petty
authors.affiliation: Laboratory of Virology, Divisions of Infectious Diseases and Laboratory Medicine.
authors.forename: Samuel
authors.initials: S
authors.lastname: Cordey
authors.affiliation: Laboratory of Virology, Divisions of Infectious Diseases and Laboratory Medicine.
authors.forename: Yves
authors.initials: Y
authors.lastname: Thomas
authors.affiliation: Centre Hospitalier Universitaire de Québec and Université Laval, Quebec City, Canada.
authors.forename: Xavier
authors.initials: X
authors.lastname: Bouhy
authors.affiliation: Laboratory of Virology, Divisions of Infectious Diseases and Laboratory Medicine.
authors.forename: Manuel
authors.initials: M
authors.lastname: Schibler
authors.affiliation: Division of Hematology, Department of Internal Medicine Specialties, University of Geneva Hospitals.
authors.forename: Audrey
authors.initials: A
authors.lastname: Simon
authors.affiliation: Division of Hematology, Department of Internal Medicine Specialties, University of Geneva Hospitals.
authors.forename: Yves
authors.initials: Y
authors.lastname: Chalandon
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine Specialties, University of Geneva Hospitals.
authors.forename: Christian
authors.initials: C
authors.lastname: van Delden
authors.affiliation: Department of Genetic Medicine and Development, University of Geneva Medical School Swiss Institute of Bioinformatics, University of Geneva, Switzerland.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Zdobnov
authors.affiliation: Laboratory of Virology, Divisions of Infectious Diseases and Laboratory Medicine.
authors.forename: Patricia
authors.initials: P
authors.lastname: Boquete-Suter
authors.affiliation: Centre Hospitalier Universitaire de Québec and Université Laval, Quebec City, Canada.
authors.forename: Guy
authors.initials: G
authors.lastname: Boivin
authors.affiliation: Laboratory of Virology, Divisions of Infectious Diseases and Laboratory Medicine University of Geneva Medical School, University of Geneva, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Kaiser
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D024882:Drug Resistance, Viral / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000235:genetics*; D007251:Influenza, Human / Q000821:virology; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics / Q000502:physiology; D009296:Nasal Cavity / Q000821:virology; D009439:Neuraminidase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D033581:Stem Cell Transplantation; D053243:Zanamivir / Q000494:pharmacology
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D009439:Neuraminidase; D053243:Zanamivir
keywords: H1N1 influenza; immunosuppression; oseltamivir; resistance; zanamivir