title: Low incidence of rimantadine resistance in field isolates of influenza A viruses.
abstract: The spread of drug-resistant influenza viruses type A to close contacts in families, schools, and nursing homes has been well documented. To investigate whether drug-resistant influenza viruses circulate in the general population, 2017 isolates collected in 43 countries and territories during a 4-year period were tested for drug susceptibility in a bioassay. Drug resistance was confirmed by detection of specific mutations on the M2 gene that have been shown to confer resistance to amantadine or rimantadine. Sixteen viruses (0.8%) were found to be drug-resistant. Only 2 of these resistant viruses were isolated from individuals who received amantadine or rimantadine treatment at the time the specimens were collected. For 12 individuals use of amantadine or rimantadine could be excluded, and from the remaining 2 patients information about medication was unavailable. These results indicate that the circulation of drug-resistant influenza viruses is a rare event, but surveillance for drug resistance should be continued.
authors.affiliation: Department of Medical Microbiology, University of Oulu, FIN-90401 Oulu, Finland. thedi.ziegler@oulu.fi
authors.forename: T
authors.initials: T
authors.lastname: Ziegler
authors.forename: M L
authors.initials: ML
authors.lastname: Hemphill
authors.forename: M L
authors.initials: ML
authors.lastname: Ziegler
authors.forename: G
authors.initials: G
authors.lastname: Perez-Oronoz
authors.forename: A I
authors.initials: AI
authors.lastname: Klimov
authors.forename: A W
authors.initials: AW
authors.lastname: Hampson
authors.forename: H L
authors.initials: HL
authors.lastname: Regnery
authors.forename: N J
authors.initials: NJ
authors.lastname: Cox
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D001681:Biological Assay; D002460:Cell Line; D004285:Dogs; D004352:Drug Resistance, Microbial; D014943:Global Health; D006801:Humans; D009980:Influenza A virus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D007251:Influenza, Human / Q000635:transmission / Q000821:virology; D008826:Microbial Sensitivity Tests; D012299:Rimantadine / Q000494:pharmacology*; D014763:Viral Matrix Proteins / Q000235:genetics; D000086082:Viroporin Proteins
chemical_list: D000998:Antiviral Agents; D012299:Rimantadine; D014763:Viral Matrix Proteins; C031540:M-protein, influenza virus; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins