Giuseppe
Emeritus
[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]
Antiviral susceptibility of variant influenza A(H3N2)v viruses isolated in the United States during 2011 ? 2013
K. Sleeman 1, V. P. Mishin 1, Z. Guo 1, R. J. Garten 1, A. Balish 1, Alicia M. Fry 2, J. Villanueva 1, J. Stevens 1 and L. V. Gubareva 1#
Author Affiliations: <SUP>1</SUP>Virology, Surveillance and Diagnosis Branch <SUP>2</SUP> Epidemiology and Prevention Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
Published ahead of print 21 January 2014, doi: 10.1128/AAC.02556-13 <CITE>AAC.02556-13 </CITE>
<CITE></CITE>
<CITE></CITE>
<CITE></CITE>ABSTRACT
Since 2011, outbreaks caused by influenza A(H3N2) variant [A(H3N2)v] viruses have become a public health concern in the United States. The A(H3N2)v viruses share the A(H1N1)pdm09 M gene containing the marker of M2 blocker resistance, S31N, but do not contain any known molecular markers associated with resistance to neuraminidase (NA) inhibitors (NAIs). Using a fluorescent NA inhibition (NI) assay the susceptibilities of recovered A(H3N2)v viruses (n=168) were assessed to FDA-approved (oseltamivir and zanamivir) and other (peramivir, laninamivir, and A-315675) NAIs. All A(H3N2)v viruses tested, with the exception of a single virus, A/Ohio/88/2012, isolated from an untreated patient, were susceptible to the NAIs tested. The A/Ohio/88/2012 virus contained two rare substitutions S245N and S247P in the NA and demonstrated reduced inhibition by oseltamivir (31-fold) and zanamivir (66-fold) in the NI assay. Using recombinant NA (recNA) proteins, S247P was shown to be responsible for the observed altered NAI susceptibility, in addition to an approximately 60% reduction in NA enzymatic activity. The S247P substitution has not been previously reported as a molecular marker of reduced susceptibility to the NAIs. Using cell culture assays the investigational antiviral drugs nitazoxanide, favipiravir, and fludase were shown to inhibit the replication of A(H3N2)v viruses, including the virus with the S247P substitution in the NA. This report demonstrates the importance of continuous monitoring of susceptibility of zoonotic influenza viruses to available and investigational antiviral drugs.
FOOTNOTES
#Author for correspondence: Larisa V. Gubareva, Virology, Surveillance and Diagnosis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road NE, MS?G16, Atlanta, GA 30333, USA. Telephone: +1 404 639 3204; FAX: +1 404 639 0800; E-mail: LGubareva@cdc.gov
Copyright ? 2014, American Society for Microbiology. All Rights Reserved.
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Antiviral susceptibility of variant influenza A(H3N2)v viruses isolated in the United States during 2011 ? 2013
K. Sleeman 1, V. P. Mishin 1, Z. Guo 1, R. J. Garten 1, A. Balish 1, Alicia M. Fry 2, J. Villanueva 1, J. Stevens 1 and L. V. Gubareva 1#
Author Affiliations: <SUP>1</SUP>Virology, Surveillance and Diagnosis Branch <SUP>2</SUP> Epidemiology and Prevention Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
Published ahead of print 21 January 2014, doi: 10.1128/AAC.02556-13 <CITE>AAC.02556-13 </CITE>
<CITE></CITE>
<CITE></CITE>
<CITE></CITE>ABSTRACT
Since 2011, outbreaks caused by influenza A(H3N2) variant [A(H3N2)v] viruses have become a public health concern in the United States. The A(H3N2)v viruses share the A(H1N1)pdm09 M gene containing the marker of M2 blocker resistance, S31N, but do not contain any known molecular markers associated with resistance to neuraminidase (NA) inhibitors (NAIs). Using a fluorescent NA inhibition (NI) assay the susceptibilities of recovered A(H3N2)v viruses (n=168) were assessed to FDA-approved (oseltamivir and zanamivir) and other (peramivir, laninamivir, and A-315675) NAIs. All A(H3N2)v viruses tested, with the exception of a single virus, A/Ohio/88/2012, isolated from an untreated patient, were susceptible to the NAIs tested. The A/Ohio/88/2012 virus contained two rare substitutions S245N and S247P in the NA and demonstrated reduced inhibition by oseltamivir (31-fold) and zanamivir (66-fold) in the NI assay. Using recombinant NA (recNA) proteins, S247P was shown to be responsible for the observed altered NAI susceptibility, in addition to an approximately 60% reduction in NA enzymatic activity. The S247P substitution has not been previously reported as a molecular marker of reduced susceptibility to the NAIs. Using cell culture assays the investigational antiviral drugs nitazoxanide, favipiravir, and fludase were shown to inhibit the replication of A(H3N2)v viruses, including the virus with the S247P substitution in the NA. This report demonstrates the importance of continuous monitoring of susceptibility of zoonotic influenza viruses to available and investigational antiviral drugs.
FOOTNOTES
#Author for correspondence: Larisa V. Gubareva, Virology, Surveillance and Diagnosis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road NE, MS?G16, Atlanta, GA 30333, USA. Telephone: +1 404 639 3204; FAX: +1 404 639 0800; E-mail: LGubareva@cdc.gov
Copyright ? 2014, American Society for Microbiology. All Rights Reserved.
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