title: [Resistance to amantadine of epidemic strain of H3 subtype influenza virus: a primary study].
abstract: OBJECTIVE
  To study the resistance to amantadine of epidemic strain of H3 subtype influenza virus.
  
  
  METHODS
  Forty-one strains of influenza virus were isolated from pediatric patients with influenza in Beijing 2004-2005 and were identified as H3 subtype. RNA was extracted. Thirty of the 40 strains were resistant to amantadine with a resistance rate of 75%. The M2 gene ion channel fragments were amplified by one-step RT-PCR, sequenced, and then underwent systemic tree analysis.
  
  
  RESULTS
  M2 ion channel associated gene fragment with a molecular size of 153 bp was obtained. The amino acid at the site 31 changed from serine into asparagines, a mutation identical to that of the reference strain A/PR8/34 resistant to amantadine.
  
  
  CONCLUSIONS
  The resistance rate to amantadine is high among the epidemic strains of H3 subtype influenza virus in China. The associated mutation occurs at the site 31 of M2 protein.
authors.affiliation: Institute for Viral Disease Control and Prevention, China Centre for Disease Control and Prevention, Beijing 100052, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Qian
authors.forename: Hang
authors.initials: H
authors.lastname: Xu
authors.forename: Jia-huai
authors.initials: JH
authors.lastname: Zhang
authors.forename: Ru-nan
authors.initials: RN
authors.lastname: Zhu
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
mesh_terms: D000547:Amantadine / Q000494:pharmacology*; D000998:Antiviral Agents / Q000494:pharmacology; D002648:Child; D002681:China / Q000453:epidemiology; D004252:DNA Mutational Analysis; D024882:Drug Resistance, Viral / Q000235:genetics; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology / Q000821:virology*; D008826:Microbial Sensitivity Tests; D009154:Mutation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014763:Viral Matrix Proteins / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics; D000086082:Viroporin Proteins
chemical_list: D000547:Amantadine; D000998:Antiviral Agents; D014763:Viral Matrix Proteins; D014764:Viral Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins