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Surveillance for neuraminidase-inhibitor-resistant influenza viruses in Japan, 1996-2007.
Antivir Ther 2009; 14(6):751-61AT

Abstract

BACKGROUND

High usage of the neuraminidase inhibitor (NAI) oseltamivir in Japan since 2003 led the Neuraminidase Inhibitor Susceptibility Network to assess the susceptibility of community isolates of influenza viruses to oseltamivir and zanamivir.

METHODS

Isolates were tested by the enzyme inhibition assay and by neuraminidase (NA) sequence analysis.

RESULTS

Among 1,141 A(H3N2) viruses and 171 type B viruses collected in Japan during the 2003-2004 season, 3 (0.3%) A(H3N2) isolates showed high 50% inhibitory concentrations (IC(50)) to oseltamivir. Each possessed a known resistance NA mutation at R292K or E119V. During the 2004-2005 season, no resistance was found among 567 influenza A(H3N2) or 60 A(H1N1) isolates, but 1 of 58 influenza B isolates had an NAI resistance mutation (D197N). Sequence analysis found that 4 (3%) of 132 A(H1N1) viruses from 2005-2006 had known NA resistance mutations (all H274Y), but no additional resistant isolates were detected from that or the subsequent 2006-2007 season. Concurrent testing of a selection of 500 influenza B viruses from 2000 to 2006 showed significant variations between seasons in both oseltamivir and zanamivir IC(50) values, but no persistent increases over this period.

CONCLUSIONS

Our findings suggested possible low-level transmission of resistant variants from oseltamivir-treated patients in several seasons in Japan but no sustained reductions in NAI susceptibility or consistently increased frequency of detecting resistant variants for any strain or subtype, despite high levels of drug use. In particular, although oseltamivir-resistant A(H1N1) viruses with the H274Y mutation spread globally in 2007-2008, we found little evidence for increasing levels of resistant A(H1N1) variants in Japan in preceding years.

Authors+Show Affiliations

WHO Collaborating Center for Reference & Research on Influenza, National Institute of Infectious Diseases, Tokyo, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19812437

Citation

Tashiro, Masato, et al. "Surveillance for Neuraminidase-inhibitor-resistant Influenza Viruses in Japan, 1996-2007." Antiviral Therapy, vol. 14, no. 6, 2009, pp. 751-61.
Tashiro M, McKimm-Breschkin JL, Saito T, et al. Surveillance for neuraminidase-inhibitor-resistant influenza viruses in Japan, 1996-2007. Antivir Ther (Lond). 2009;14(6):751-61.
Tashiro, M., McKimm-Breschkin, J. L., Saito, T., Klimov, A., Macken, C., Zambon, M., & Hayden, F. G. (2009). Surveillance for neuraminidase-inhibitor-resistant influenza viruses in Japan, 1996-2007. Antiviral Therapy, 14(6), pp. 751-61. doi:10.3851/IMP1194.
Tashiro M, et al. Surveillance for Neuraminidase-inhibitor-resistant Influenza Viruses in Japan, 1996-2007. Antivir Ther (Lond). 2009;14(6):751-61. PubMed PMID: 19812437.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Surveillance for neuraminidase-inhibitor-resistant influenza viruses in Japan, 1996-2007. AU - Tashiro,Masato, AU - McKimm-Breschkin,Jennifer L, AU - Saito,Takehiko, AU - Klimov,Alexander, AU - Macken,Catherine, AU - Zambon,Maria, AU - Hayden,Frederick G, AU - ,, PY - 2009/10/9/entrez PY - 2009/10/9/pubmed PY - 2009/12/16/medline SP - 751 EP - 61 JF - Antiviral therapy JO - Antivir. Ther. (Lond.) VL - 14 IS - 6 N2 - BACKGROUND: High usage of the neuraminidase inhibitor (NAI) oseltamivir in Japan since 2003 led the Neuraminidase Inhibitor Susceptibility Network to assess the susceptibility of community isolates of influenza viruses to oseltamivir and zanamivir. METHODS: Isolates were tested by the enzyme inhibition assay and by neuraminidase (NA) sequence analysis. RESULTS: Among 1,141 A(H3N2) viruses and 171 type B viruses collected in Japan during the 2003-2004 season, 3 (0.3%) A(H3N2) isolates showed high 50% inhibitory concentrations (IC(50)) to oseltamivir. Each possessed a known resistance NA mutation at R292K or E119V. During the 2004-2005 season, no resistance was found among 567 influenza A(H3N2) or 60 A(H1N1) isolates, but 1 of 58 influenza B isolates had an NAI resistance mutation (D197N). Sequence analysis found that 4 (3%) of 132 A(H1N1) viruses from 2005-2006 had known NA resistance mutations (all H274Y), but no additional resistant isolates were detected from that or the subsequent 2006-2007 season. Concurrent testing of a selection of 500 influenza B viruses from 2000 to 2006 showed significant variations between seasons in both oseltamivir and zanamivir IC(50) values, but no persistent increases over this period. CONCLUSIONS: Our findings suggested possible low-level transmission of resistant variants from oseltamivir-treated patients in several seasons in Japan but no sustained reductions in NAI susceptibility or consistently increased frequency of detecting resistant variants for any strain or subtype, despite high levels of drug use. In particular, although oseltamivir-resistant A(H1N1) viruses with the H274Y mutation spread globally in 2007-2008, we found little evidence for increasing levels of resistant A(H1N1) variants in Japan in preceding years. SN - 1359-6535 UR - https://www.unboundmedicine.com/medline/citation/19812437/Surveillance_for_neuraminidase_inhibitor_resistant_influenza_viruses_in_Japan_1996_2007_ L2 - https://medlineplus.gov/flu.html DB - PRIME DP - Unbound Medicine ER -