Abstract: CONCLUSION: Seasonal oseltamivir-resistant influenza A(H1N1) viruses with NA gene H274Y mutation are transmitted and retain significant pathogenicity and lethality in high-risk patients.
Abstract: CONTEXT: The sudden emergence and rapid spread of oseltamivir-resistant influenza A(H1N1) viruses with neuraminidase (NA) gene H274Y amino acid substitution is the hallmark of global seasonal influenza since January 2008.
Abstract: DESIGN, SETTING, AND PATIENTS: Descriptive outbreak investigation of 2 hematopoietic stem cell transplant recipients and an elderly patient who developed hospital-acquired influenza A virus infection following exposure to an index patient with community-acquired H274Y-mutated influenza A(H1N1) virus in
Computational studies of H5N1 influenza virus resistance to oseltamivir.
Abstract: Detailed analyses indicated that conformational change of E276 in the Pocket 1 region of NA is a key source of drug resistance in the H274Y mutant but not in the N294S mutant.
Abstract: We examined two resistant NA mutations, H274Y and N294S, and one non-drug-resistant mutation, E119G.
Oseltamivir-resistant influenza virus A (H1N1), Europe, 2007-08 season.
Introduction: In late January 2008, we reported an unexpected high level and unexpected spread of oseltamivir-resistant influenza viruses A (H1N1) (ORVs) in Europe caused by a H275Y (H274Y in N2 numbering) amino acid substitution in the neuraminidase (NA) of these viruses.
Figure: Sequences of oseltamivir-resistant viruses, possessing the H275Y (H274Y in N2 numbering) mutation are in boldface; vaccine strains are in italics.
The origin and global emergence of adamantane resistant A/H3N2 influenza viruses.
Discussion: Finally, the processes of local evolution, reassortment, and global spread through genomic hitchhiking we observe in the spread of S31N among A/H3N2 viruses are also likely to be involved in the recent global proliferation of A/H1N1 influenza viruses that are resistant to adamantanes, as well as in the unexpected proliferation of the H274Y substitution conferring resistance to NA inhibitors (oseltamivir).
Genetic microheterogeneity of emerging H275Y influenza virus A (H1N1) in Toronto, Ontario, Canada from the 2007-2008 respiratory season.
Abstract: BACKGROUND: The H275Y mutation (H274Y in N2 numbering) in the neuraminidase (NA) gene (segment 6) of the influenza virus A (H1N1) genome is linked to oseltamivir resistance.
Surveillance and oseltamivir resistance of human influenza a virus in Turkey during the 2007-2008 season.
Abstract: H275Y (H274Y according to N2 numbering) mutation, which is known to confer resistance to oseltamivir, was detected in 6 out of 30 (20%) H1N1 isolates from four cities (Istanbul, Bursa, Ankara, and Izmir).
Novel pandemic influenza A(H1N1) viruses are potently inhibited by DAS181, a sialidase fusion protein.
Discussion: Because the pandemic influenza A(H1N1) virus, or any other emerging strain of influenza, could potentially gain the oseltamivir-resistance mutation (H274Y) it is critical to continue to develop anti-influenza compounds with alternative mechanisms of action.
Discussion: The most common mutation conferring oseltamivir-resistance involves H274Y (H275Y in N1 numbering) substitution in the neuraminidase of viruses of N1 antigenic subtype (H1N1 and H5N1).
Discussion: This in vitro finding indicates that DAS181 may be active against currently circulating oseltamivir-resistant IFV and further suggests that if novel strains, such as the pandemic influenza A(H1N1) viruses, attain the H274Y mutation, DAS181 may be active against these new isolates as w
Inhibition of neuraminidase inhibitor-resistant influenza virus by DAS181, a novel sialidase fusion protein.
Introduction: However, because of the ease of transmission and significant pathogenicity in high risk patients, it is now concluded that the current oseltamivir-resistant H274Y mutant likely possesses the same degree of virulence as the wild-type strain.
Introduction: Interestingly, this H274Y mutation was once believed to confer reduced viral fitness.
Introduction: The frequency of isolates with the H274Y mutation has increased with each flu season, including in countries that do not regularly prescribe oseltamivir.
Introduction: While neuraminidase inhibitor (NAI)-resistance has been observed to occur via different molecular mechanisms, the dominating change conferring oseltamivir-resistance in the current seasonal IFV is a mutation in the neuraminidase (
Clinical effectiveness of oseltamivir and zanamivir for treatment of influenza A virus subtype H1N1 with the H274Y mutation: a Japanese, multicenter study of the 2007-2008 and 2008-2009 influenza seasons.
Abstract: All 49 analyzed H1N1 virus isolates obtained during the 2008-2009 season, but none of the isolates obtained during the 2007-2008 season, contained the H274Y mutation.
Abstract: BACKGROUND: Influenza A virus subtype H1N1 with the H274Y mutation emerged and spread worldwide.
Abstract: The H274Y neuraminidase mutation status was determined by sequencing the neuraminidase segment.
Oseltamivir resistance and the H274Y neuraminidase mutation in seasonal, pandemic and highly pathogenic influenza viruses.
Abstract: Fortunately, the current pandemic A(H1N1) 2009 virus, which is circulating globally, remains largely sensitive to both NAIs, although a small number of oseltamivir-resistant viruses have been isolated from patients to date, again with the H274Y mutation.
Abstract: Recently, however, significant levels of oseltamivir-resistant influenza A(H1) seasonal influenza viruses have also been encountered, which has been associated with a single amino acid change in the viral neuraminidase (H274Y).
IV mutation literature information.
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