High incidence of amantadine-resistant influenza AH3 viruses isolated during the 2005-2006 winter season in Nara, Japan.
We examined the incidence of amantadine-resistant influenza AH3 viruses isolated in Nara Prefecture during the 2005-06 winter season. The genetic analyses of the M2 ion channel protein were conducted using reverse transcriptase PCR and direct sequencing. Thirteen out of 18 (72.2%) strains were identified as amantadine-resistant, and this incidence was remarkably higher than those previously recored in Nara Prefecture. Genetic analyses of the viruses revealed that all the anti-drug strains contained a change at position 31 (AGT-->AAT, Ser31Asn) in the M2 gene. One of the 13 amantadine-resistant strains also contained a change at position 27 (GTT-->GCT, Val27Ala). Our data indicate that there has been a significant increase of drug-resistant influenza AH3 viruses in Nara Prefecture, and raise concern about the spread of resistant influenza AH3 viruses in Japan.
Yoneda
Masaki
M
Virology and Bacteriology Division, Nara Prefectural Institute for Hygiene and Environment, Nara 630-8131, Japan. mk.yoneda@ihe.pref.nara.jp
Inoue
Yumiko
Y
Kitahori
Yoshiteru
Y
D000547:Amantadine / Q000494:pharmacology*; D024882:Drug Resistance, Viral; D006801:Humans; D009980:Influenza A virus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology / Q000821:virology*; D007564:Japan / Q000453:epidemiology; D017354:Point Mutation; D014763:Viral Matrix Proteins / Q000235:genetics; D000086082:Viroporin Proteins
D000547:Amantadine; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins