Table 3.
Genotypic (NA) and phenotypic (NA Star assay) analysis of resistant influenza A/H1N1 viruses
| Subject no. | Season | Visit (day) | Source | ZMV |
OSV |
Amino acid substitutions (N2 numbering)b | ||
|---|---|---|---|---|---|---|---|---|
| IC50 (nM) | FCa | IC50 (nM) | FC | |||||
| 1 | 2006-2007 | 1 | Swab | NAd | NA | NA | NA | N74S, P82S, K130R, I187 M, G248R, M266I, T286I, N347D, G357D, I370L, I397V, I454Tc |
| 1 | 2006-2007 | 1 | Culture | 19.5e | 46e | 1.8 | 2.7 | N74S, P82S, K130R, I187 M, G248R, M266I, T286I, N347D, G357D, I370L, I397V, I454Tc |
| 2 | 2007-2008 | 1 | Swab | NA | NA | NA | NA | A86V, V94I, N208K, Q216K, G331R, S452G |
| 2 | 2007-2008 | 2 | Swab | NA | NA | NA | NA | A86V, V94I, N208K, Q216K, G331R, S452G |
| 2 | 2007-2008 | 1 | Culture | 280.7 | 292 | 0.62 | 0.84 | A86V, V94I, Q136K, N208K, Q216K, G331R, S452G |
| 2 | 2007-2008 | 2 | Culture | 289.2 | 300 | 0.59 | 0.80 | A86V, V94I, Q136K, N208K, Q216K, G331R, S452G |
a
FC, fold change.
b
Resistance-associated amino acid substitutions are in bold.
c
Four viruses with the same sequence but without N74S did not show reduced susceptibility to zanamivir.
d
NA, not applicable.
e
On retesting, the IC50 was 12.9 nM and the fold change was 31.