title: [Susceptibility of human influenza A (H3N2) viruses to neuraminidase inhibitors isolated during 2011-2012 in China].
abstract: OBJECTIVE
  To analyze the susceptibility of influenza A (H3N2) viruses to neuraminidase inhibitors during 2011-2012 in Mainland China.
  
  
  METHODS
  All the tested viruses were obtained from the Chinese National Influenza Surveillance Network, which covers 31 provinces in mainland China, including 408 network laboratories and 554 sentinel hospitals. In total 1 903 viruses were selected with isolation date from January 1, 2011 to December 31, 2012 in Mainland China, among these viruses, 721 were confirmed to be influenza A (H3N2) virus by Chinese National Influenza Center and tested for the susceptibility to oseltamivir and zanamivir using chemiluminescence-based assay. The neuraminidase inhibitor sensitive reference virus A/Washington/01/2007 (119E) and oseltamivir resistant virus A/Texas/12/2007 (E119V) were used as control in this study. The t -test was used to compare the difference of NAI susceptibility of viruses isolated from different years.
  
  
  RESULTS
  The half maximal inhibitory concentration (IC₅₀) of A/Washington/01/2007 for oseltamivir and zanamivir was (0.10 ± 0.02) and (0.30 ± 0.05) nmol/L, respectively. The IC₅₀ of A/Texas/12/2007 for oseltamivir and zanamivir was (4.27 ± 1.60) and (0.20 ± 0.03) nmol/L, respectively. Among the 721 influenza A (H3N2) viruses, 132 influenza A (H3N2) viruses were isolated in 2011 and 589 influenza A (H3N2) viruses were isolated in 2012. The IC50 for oseltamivir ranged from 0.04 to 0.62 nmol/L for viruses isolated in 2011 and ranged from 0.02 to 0.95 nmol/L for viruses in 2012, and the IC₅₀ of all the viruses tested was within 10-fold IC₅₀ (1.0 nmol/L) of the neuraminidase inhibitor sensitive reference virus A/Washington/01/2007. The IC50 of zanamivir ranged from 0.12 to 0.80 nmol/L for viruses in 2011 and ranged from 0.04 to 0.72 nmol/L for viruses in 2012, and was within 10-fold IC₅₀ (3.0 nmol/L) of the neuraminidase inhibitor sensitive reference virus A/Washington/01/2007.
  
  
  CONCLUSIONS
  The influenza A(H3N2) viruses isolated during 2011-2012 in Mainland China were tested to be sensitive to oseltamivir and zanamivir.
authors: Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health, Beijing102206, China.
authors: Weijuan
authors: W
authors: Huang
authors: Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health, Beijing102206, China.
authors: Minju
authors: M
authors: Tan
authors: Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health, Beijing102206, China.
authors: Xiang
authors: X
authors: Zhao
authors: Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health, Beijing102206, China.
authors: Yanhui
authors: Y
authors: Cheng
authors: Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health, Beijing102206, China.
authors: Xiyan
authors: X
authors: Li
authors: Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health, Beijing102206, China.
authors: Junfeng
authors: J
authors: Guo
authors: Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health, Beijing102206, China.
authors: Hejiang
authors: H
authors: Wei
authors: Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health, Beijing102206, China.
authors: Ning
authors: N
authors: Xiao
authors: Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health, Beijing102206, China.
authors: Zhao
authors: Z
authors: Wang
authors: Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health, Beijing102206, China; Email: dayanwang@cnic.org.cn.
authors: Dayan
authors: D
authors: Wang
authors: Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health, Beijing102206, China.
authors: Yuelong
authors: Y
authors: Shu
mesh_terms: D000998:Antiviral Agents; D002681:China; D024882:Drug Resistance, Viral; D004791:Enzyme Inhibitors; D062665:Epidemiological Monitoring; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype; D007251:Influenza, Human; D009439:Neuraminidase; D053139:Oseltamivir; D053243:Zanamivir
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D053139:Oseltamivir; D009439:Neuraminidase; D053243:Zanamivir