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Basic Characteristics of Mutations
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Mutation Site
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I222R |
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Mutation Site Sentence
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METHODS: Four NA variants of A/Taiwan/1/2013(H7N9) virus containing a single substitution (NA-E119V, NA-I222K, NA-I222R, or NA-R292K) recovered from an oseltamivir-treated patient were tested for NAI susceptibility in vitro; their replicative fitness was evaluated in cell culture, mice, and ferrets. |
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Mutation Level
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Amino acid level |
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Mutation Type
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Nonsynonymous substitution |
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Gene/Protein/Region
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NA |
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Standardized Encoding Gene
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NA
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Genotype/Subtype
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H7N9 |
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Viral Reference
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EPI445909–EPI445916
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Functional Impact and Mechanisms
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Disease
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Influenza A
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Immune
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- |
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Target Gene
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-
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Clinical and Epidemiological Correlations
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Clinical Information
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- |
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Treatment
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oseltamivir |
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Location
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China |
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Literature Information
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PMID
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25124927
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Title
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Characterization of drug-resistant influenza A(H7N9) variants isolated from an oseltamivir-treated patient in Taiwan
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Author
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Marjuki H,Mishin VP,Chesnokov AP,Jones J,De La Cruz JA,Sleeman K,Tamura D,Nguyen HT,Wu HS,Chang FY,Liu MT,Fry AM,Cox NJ,Villanueva JM,Davis CT,Gubareva LV
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Journal
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The Journal of infectious diseases
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Journal Info
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2015 Jan 15;211(2):249-57
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Abstract
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BACKGROUND: Patients contracting influenza A(H7N9) infection often developed severe disease causing respiratory failure. Neuraminidase (NA) inhibitors (NAIs) are the primary option for treatment, but information on drug-resistance markers for influenza A(H7N9) is limited. METHODS: Four NA variants of A/Taiwan/1/2013(H7N9) virus containing a single substitution (NA-E119V, NA-I222K, NA-I222R, or NA-R292K) recovered from an oseltamivir-treated patient were tested for NAI susceptibility in vitro; their replicative fitness was evaluated in cell culture, mice, and ferrets. RESULTS: NA-R292K led to highly reduced inhibition by oseltamivir and peramivir, while NA-E119V, NA-I222K, and NA-I222R caused reduced inhibition by oseltamivir. Mice infected with any virus showed severe clinical signs with high mortality rates. NA-I222K virus was the most virulent in mice, whereas virus lacking NA change (NA-WT) and NA-R292K virus seemed the least virulent. Sequence analysis suggests that PB2-S714N increased virulence of NA-I222K virus in mice; NS1-K126R, alone or in combination with PB2-V227M, produced contrasting effects in NA-WT and NA-R292K viruses. In ferrets, all viruses replicated to high titers in the upper respiratory tract but produced only mild illness. NA-R292K virus, showed reduced replicative fitness in this animal model. CONCLUSIONS: Our data highlight challenges in assessment of the replicative fitness of H7N9 NA variants that emerged in NAI-treated patients.
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Sequence Data
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-
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