Emergence of H274Y oseltamivir-resistant A(H1N1) influenza viruses in Japan during the 2008–2009 season

Baranovich, Tatiana; Saito, Reiko; Suzuki, Yasushi; Zaraket, Hassan; Dapat, Clyde; Caperig-Dapat, Isolde; Oguma, Taeko; Shabana, Iman Ibrahim; Saito, Takehiko; Suzuki, Hiroshi; the Japanese Influenza Collaborative Study Group,

doi:10.1016/j.jcv.2009.11.003

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Volume 47, Issue 1 , Pages 23-28, January 2010

Emergence of H274Y oseltamivir-resistant A(H1N1) influenza viruses in Japan during the 2008–2009 season

Tatiana Baranovich
- Division of Public Health, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757, Asahimachi-Dori, Chuoku, Niigata City, Niigata Prefecture 951-8510, Japan
- Corresponding author. Tel.: +81 25 227 2129; fax: +81 25 227 0765.
Reiko Saito
- Division of Public Health, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757, Asahimachi-Dori, Chuoku, Niigata City, Niigata Prefecture 951-8510, Japan
Yasushi Suzuki
- Division of Public Health, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757, Asahimachi-Dori, Chuoku, Niigata City, Niigata Prefecture 951-8510, Japan
Hassan Zaraket
- Division of Public Health, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757, Asahimachi-Dori, Chuoku, Niigata City, Niigata Prefecture 951-8510, Japan
Clyde Dapat
- Division of Public Health, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757, Asahimachi-Dori, Chuoku, Niigata City, Niigata Prefecture 951-8510, Japan
Isolde Caperig-Dapat
- Division of Public Health, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757, Asahimachi-Dori, Chuoku, Niigata City, Niigata Prefecture 951-8510, Japan
Taeko Oguma
- Division of Public Health, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757, Asahimachi-Dori, Chuoku, Niigata City, Niigata Prefecture 951-8510, Japan
Iman Ibrahim Shabana
- Division of Public Health, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757, Asahimachi-Dori, Chuoku, Niigata City, Niigata Prefecture 951-8510, Japan
Takehiko Saito
- National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
Hiroshi Suzuki
- Division of Public Health, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757, Asahimachi-Dori, Chuoku, Niigata City, Niigata Prefecture 951-8510, Japan
the Japanese Influenza Collaborative Study Group
- Contributing members of the Japanese Influenza Collaborative Study Group are listed in ‘Acknowledgments’ section.

Received 25 August 2009; accepted 4 November 2009. published online 04 December 2009.

Abstract

Background

A substantial increase in oseltamivir-resistant A(H1N1) influenza viruses was reported in Europe in late 2007.

Objectives

To monitor the antiviral susceptibility profile of human A(H1N1) influenza viruses in Japan during the 2007–2008 and 2008–2009 seasons.

Study design

Viruses were obtained from respiratory samples of patients with influenza collected in Japan between December 2007 and April 2008 (n=1046) and between December 2008 and April 2009 (n=1789). Oseltamivir resistance was determined by an H274Y-specific real-time PCR cycling probe assay and a neuraminidase inhibition assay. Amantadine resistance was assessed by sequencing the M2 gene. Sequencing of the hemagglutinin and NA genes was performed to infer phylogenetic relationships between different strains.

Results

Three of 687 (0.4%) A(H1N1) viruses from the 2007–2008 season and 745 of 745 (100%) viruses from the 2008–2009 season carried the NA–H274Y substitution and demonstrated a >300-fold reduction in oseltamivir susceptibility. All oseltamivir-resistant viruses from the 2008–2009 season possessed an A193T substitution in the receptor-binding domain of the hemagglutinin. Amantadine resistance was detected in 431 of 687 (62.7%) and 0 of 745 (0.0%) of the A(H1N1) viruses from the 2007–2008 and 2008–2009 seasons, respectively.

Conclusions

A dramatic surge in oseltamivir-resistant A(H1N1) viruses possessing the NA–H274Y substitution was detected in Japan during the 2008–2009 season. The emergence of oseltamivir-resistant viruses was facilitated by mutations in the viral genome. Intensified surveillance, including phenotypic assays and sequencing of the hemagglutinin, neuraminidase, and M2 gene would allow monitoring of the spread and evolution of drug-resistant influenza virus variants.

Abbreviations: NAI, neuraminidase inhibitors, H, histidine, Y, tyrosine, NA, neuraminidase, MDCK, Madin Darby canine kidney, MUNANA, methyl umbelliferone N-acetyl neuraminic acid, HA, hemagglutinin