Frequency of oseltamivir resistance in Sydney, during the Newcastle outbreak of community transmitted oseltamivir-resistant influenza A(H1N1)pdm09 virus, Australia, June to August 2011

B Wang; J Taylor; M Ratnamohan; K McPhie; A Kesson; R Dixit; R Booy; A C Hurt; N K Saksena; D E Dwyer

doi:10.2807/ese.17.27.20210-en

Surveillance and outbreak reports Open Access

Like 0

Download

Frequency of oseltamivir resistance in Sydney, during the Newcastle outbreak of community transmitted oseltamivir-resistant influenza A(H1N1)pdm09 virus, Australia, June to August 2011
B Wang¹ , J Taylor² , M Ratnamohan² , K McPhie² , A Kesson^3,4 , R Dixit^3,4 , R Booy^3,4 , A C Hurt⁵ , N K Saksena¹ , D E Dwyer^2,3
View Affiliations Hide Affiliations

Affiliations: ¹ Retroviral Genetics Laboratory, Centre for Virus Research, Westmead Millennium Institute, Australia ² Department of Virology, Centre for Infectious Diseases and Microbiology. Laboratory Services, ICPMR, Westmead Hospital, Australia ³ Sydney Medical School and Sydney Emerging Infections and Biosecurity Institute, University of Sydney, Australia ⁴ The Children’s Hospital at Westmead, Westmead, Australia ⁵ World Health Organization (WHO) Collaborating Centre for Reference and Research on Influenza, North Melbourne, Australia.

Correspondence:
B Wang
bin.wang sydney.edu.au
View Citation Hide Citation

Citation style for this article: Wang B, Taylor J, Ratnamohan M, McPhie K, Kesson A, Dixit R, Booy R, Hurt A C, Saksena N K, Dwyer D E. Frequency of oseltamivir resistance in Sydney, during the Newcastle outbreak of community transmitted oseltamivir-resistant influenza A(H1N1)pdm09 virus, Australia, June to August 2011 . Euro Surveill. 2012;17(27):pii=20210. https://doi.org/10.2807/ese.17.27.20210-en Received: 10 Feb 2012

Abstract

Although oseltamivir-resistant pandemic influenza A(H1N1)pdm09 is uncommon in immunocompetent individuals, a recent report from Newcastle, Australia, showed the first sustained community spread, from June to August 2011, of oseltamivir-resistant influenza A(H1N1)pdm09 virus carrying the H275Y neuraminidase (NA) mutation. To determine the frequency and the extent of this viral variant spread in the nearest major city to Newcastle, we performed a sequence-based genotypic assessment on samples from 143 oseltamivir untreated and 23 oseltamivir post-treatment individuals with influenza collected contemporaneously in Sydney, 120 km southwest of Newcastle. The detection of two of 143 (1.4%) community-derived samples containing H275Y suggests a low prevalence of oseltamivir-resistant influenza A(H1N1)pdm09 virus in the general community and no convincing evidence of spread of the NA H275Y-bearing influenza A(H1N1)pdm09 virus. In oseltamivir treated patients, oseltamivir-resistant influenza A(H1N1)pdm09 virus continue to emerge with three of 23 (13%) post-treatment samples containing the H275Y mutation. The observation of signature mutations and distinct phylogenetic relationship in full-length sequences of haemagglutinin and neuraminidase genes derived from 2011 strains against 2009 strains indicates continued genetic evolution and antigenic drift of the influenza A(H1N1)pdm09 viruses circulating in Australia.