title: Zanamivir-resistant influenza viruses with Q136K or Q136R neuraminidase residue mutations can arise during MDCK cell culture creating challenges for antiviral susceptibility monitoring.
abstract: Surveillance of circulating influenza strains for antiviral susceptibility is important to ensure patient treatment guidelines remain appropriate. Influenza A(H3N2) and A(H1N1)pdm09 virus isolates containing mutations at the Q136 residue of the neuraminidase (NA) that conferred reduced susceptibility to the NA inhibitor (NAI) zanamivir were detected during antiviral susceptibility monitoring. Interestingly, the mutations were not detectable in the viruses from respective clinical specimens, only in the cultured isolates. We showed that variant viruses containing the Q136K and Q136R NA mutations were preferentially selected in Madin-Darby canine kidney epithelial (MDCK) cells, but were less well supported in MDCK-SIAT1 cells and embryonated eggs. The effect of Q136K, Q136R, Q136H and Q136L substitutions in NA subtypes N1 and N2 on NAI susceptibility and in vitro viral fitness was assessed. This study highlights the challenges that cell culture derived mutations can pose to the NAI susceptibility analysis and interpretation and reaffirms the need to sequence viruses from respective clinical specimens to avoid misdiagnosis. However, we also demonstrate that NA mutations at residue Q136 can confer reduced zanamivir, peramivir or laninamivir susceptibility, and therefore close monitoring of viruses for mutations at this site from patients being treated with these antivirals is important.
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, Melbourne, Victoria, Australia.
authors.forename: Karen
authors.initials: K
authors.lastname: Little
authors.forename: Sook-Kwan
authors.initials: SK
authors.lastname: Leang
authors.forename: Jeff
authors.initials: J
authors.lastname: Butler
authors.forename: Chantal
authors.initials: C
authors.lastname: Baas
authors.forename: Bruce
authors.initials: B
authors.lastname: Harrower
authors.forename: Jenny
authors.initials: J
authors.lastname: Mosse
authors.forename: Ian G
authors.initials: IG
authors.lastname: Barr
authors.forename: Aeron C
authors.initials: AC
authors.lastname: Hurt
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D004285:Dogs; D024882:Drug Resistance, Viral / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D053122:Influenza A Virus, H3N2 Subtype / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology; D061985:Madin Darby Canine Kidney Cells / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D009439:Neuraminidase / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014764:Viral Proteins / Q000235:genetics; D053243:Zanamivir / Q000494:pharmacology*
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D014764:Viral Proteins; D009439:Neuraminidase; D053243:Zanamivir
keywords: antimicrobial resistance; cell culture derived mutations; influenza virus; laboratory surveillance; zanamivir resistance