ABSTRACT
Objective To analyze the resistance of influenza virus to neuraminidase inhibitors (NAI) in Henan province during 2017-2018. Methods Virus were collected from the Henan Influenza Surveillance Network during 2017-2018. 36 confirmed influenza virus(with 15 H1pdm09，6 H3N2 and 15 B) were selected to test resistance to oseltamivir and zanamivi with fluorescence(FL). The NAI sensitive reference viruses were A/California/12/2012(H1pdm09)-275H,A/Beijing Haidian/1942/2014(H3N2)-119E and B/Rochester/02/2001-198D. The NAI resistant reference viruses were A/ Texas/23/2012(H1pdm9)-H275Y, A/Texas/12/2007(H3N2)-E119V and B/Rochester/02/2001-D198N. Results The half maximal inhibitory concentration(IC50) of A/California/12/2012(H1pdm09)-275H, A/Beijing-Haidian/1942/2014(H3N2)-119E and B/Rochester/02/2001-198D for oseltamivir were 0.29 nmol/L (nM),0.10 nM and 12.71 nM, and for zanamivir were 0.2 nM, 0.49 nM and 0.33 nM respectively. The IC50 for oxastatin of H1pdm09 and H3N2 ranged from (0.28-1.37 nM) and (0.08-0.17 nM) respectively, the IC50 for zanamivir ranged from (0.15-0.49 nM) and (0.12-0.22 nM), all was within 10 fold IC50 of the reference virus(corresponding type); the IC50 value of type B for oseltamivir and zanamivir ranged from (11.83-24.59 nM) and (0.48-1.25 nM), all was within 5 fold IC50 of the reference virus. Conclusion All the tested influenza strains isolated in Henan province during 2017-2018 were sensitive to NAI.