Oseltamivir-resistant influenza viruses A (H1N1) during 2007-2009 influenza seasons, Japan.
To monitor oseltamivir-resistant influenza viruses A (H1N1) (ORVs) with H275Y in neuraminidase (NA) in Japan during 2 influenza seasons, we analyzed 3,216 clinical samples by NA sequencing and/or NA inhibition assay. The total frequency of ORVs was 2.6% (45/1,734) during the 2007-08 season and 99.7% (1,477/1,482) during the 2008-09 season, indicating a marked increase in ORVs in Japan during 1 influenza season. The NA gene of ORVs in the 2007-08 season fell into 2 distinct lineages by D354G substitution, whereas that of ORVs in the 2008-09 season fell into 1 lineage. NA inhibition assay and M2 sequencing showed that almost all the ORVs were sensitive to zanamivir and amantadine. The hemagglutination inhibition test showed that ORVs were antigenetically similar to the 2008-09 vaccine strain A/Brisbane/59/2007. Our data indicate that the current vaccine or zanamivir and amantadine are effective against recent ORVs, but continuous surveillance remains necessary.
National Institute of Infectious Diseases, Musashi-Murayama, Tokyo, Japan.
Makoto
M
Ujike
Kozue
K
Shimabukuro
Kiku
K
Mochizuki
Masatsugu
M
Obuchi
Tsutomu
T
Kageyama
Masayuki
M
Shirakura
Noriko
N
Kishida
Kazuyo
K
Yamashita
Hiroshi
H
Horikawa
Yumiko
Y
Kato
Nobuyuki
N
Fujita
Masato
M
Tashiro
Takato
T
Odagiri
D000547:Amantadine / Q000494:pharmacology; D019943:Amino Acid Substitution; D000998:Antiviral Agents / Q000494:pharmacology*; D024882:Drug Resistance, Viral; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology; D007564:Japan / Q000453:epidemiology; D009439:Neuraminidase / Q000037:antagonists & inhibitors / Q000235:genetics; D053139:Oseltamivir / Q000494:pharmacology*; D010802:Phylogeny; D012621:Seasons; D020539:Sequence Analysis, Protein; D013997:Time Factors; D014763:Viral Matrix Proteins / Q000235:genetics; D053243:Zanamivir / Q000494:pharmacology; D000086082:Viroporin Proteins
D000547:Amantadine; D000998:Antiviral Agents; D009439:Neuraminidase; D053139:Oseltamivir; D014763:Viral Matrix Proteins; D053243:Zanamivir; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins