title: [Adamantane resistance among seasonal influenza A viruses between January to October in Guangzhou, 2009].
abstract: OBJECTIVE
  To study the prevalence of adamantane-resistance among influenza A viruses isolated from Guangzhou between January and October in 2009, and to provide more information for clinical usage of adamantane drugs.
  
  
  METHODS
  Totally 311 influenza A strains isolated from 6 hospitals in Guangzhou between January and October in 2009 were selected, and the MP gene of all 311 strains (159 strains of H1 subtype, 152 strains of H3 subtype) was sequenced. The susceptibility of viruses to rimantadine was assayed by biological methods in cells.
  
  
  RESULTS
  A hundred and forty-eight strains of influenza A (H1) viruses (93.1%, 148/159) were resistant to the adamantanes, and all the 152 influenza A (H3) viruses were resistant to the adamantanes. An amino acid substitution S31N was found in most of the strains except 1 strain with double mutation V27A/S31N. Furthermore, the M gene of influenza A (H1) viruses was divided into genotype B (human) (97/159) and genotype F (European and Australian birds, 62/159), while the M gene of influenza A (H3) viruses was genotype B (human) (152/152).
  
  
  CONCLUSIONS
  Resistance rate of seasonal influenza A viruses isolated from Guangzhou was high. The MP gene of influenza A (H1) may be replaced by a gene from European and Australian birds through a reassortment event.
authors.affiliation: State Key Laboratory of Respiratory Diseases (Guangzhou Medical University), the First Affiliated Hospital of Guangzhou Medical College, Guangzhou 510120, China.
authors.forename: Zi-Feng
authors.initials: ZF
authors.lastname: Yang
authors.forename: Wen-da
authors.initials: WD
authors.lastname: Guan
authors.forename: Guo-Rong
authors.initials: GR
authors.lastname: Xu
authors.forename: Ming-Yuan
authors.initials: MY
authors.lastname: Li
authors.forename: Zi-Yao
authors.initials: ZY
authors.lastname: Mo
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Wan-Ni
authors.initials: WN
authors.lastname: Dong
authors.forename: Yu-Tao
authors.initials: YT
authors.lastname: Wang
authors.forename: Sheng
authors.initials: S
authors.lastname: Qin
authors.forename: Yang-Qing
authors.initials: YQ
authors.lastname: Zhan
authors.forename: Xue
authors.initials: X
authors.lastname: Zhang
authors.forename: Qun-di
authors.initials: QD
authors.lastname: Huang
authors.forename: Shui-Shan
authors.initials: SS
authors.lastname: Zhao
authors.forename: Rong
authors.initials: R
authors.lastname: Zhou
authors.forename: Rong-Chang
authors.initials: RC
authors.lastname: Chen
authors.forename: Nan-Shan
authors.initials: NS
authors.lastname: Zhong
mesh_terms: D000218:Adamantane / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000494:pharmacology*; D002681:China; D024882:Drug Resistance, Viral; D005260:Female; D005814:Genes, Viral; D005838:Genotype; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000302:isolation & purification; D053122:Influenza A Virus, H3N2 Subtype / Q000187:drug effects* / Q000302:isolation & purification; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D000218:Adamantane