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Volume 15, Number 6—June 2009


Oseltamivir- and Amantadine-Resistant Influenza Viruses A (H1N1)

Peter K.C. Cheng, Tommy W.C. Leung, Eric C.M. Ho, Peter C.K. Leung, Anita Y.Y. Ng, Mary Y.Y. Lai, and Wilina W.L. LimComments to Author 
Author affiliations: Centre for Health Protection, Hong Kong Special Administrative Region, People’s Republic of China

Main Article


Phylogenetic analysis of HA, NA, and M2 genes of influenza viruses A (H1N1) with different drug-resistance characteristics isolated in Hong Kong, January–June 2008*

Characteristics No. isolates HA clade NA clade M2 clade Mutation
Oseltamivir resistant (n = 84)
Amantadine susceptible 81 2B† 2B 2B H274Y in NA
Amantadine resistant 1 2C† 2B 2C H274Y in NA, S31N in M2

H274Y in NA, S31N in M2
Oseltamivir susceptible (n = 37)
Amantadine susceptible 20 2B 2B 2B None
Amantadine resistant 14 2C 2C 2C S31N in M2
3 2B 2B 2C S31N in M2

*HA, hemagglutinin; NA, neuraminidase; M2, matrix.
†Clade 2B or clade 2C indicates the gene specified has a nucleotide homology >99% to that of A/Brisbane/59/2007 or A/Hong Kong/2652/2006 virus, respectively.

Main Article