Table 1. Susceptibility profiles of pH1N1 isolates, A/Brisbane/59/2007-like A/H1N1 isolates of the 2009 season, and recombinant pH1N1 viruses as tested by NA inhibition assays.
| Oseltamivir IC50 in nmol/L ± SDa | Zanamivir IC50 in nmol/L ± SDa | Peramivir IC50 in nmol/L ± SDa | A-315675 IC50 in nmol/L ± SDa | |
| Seasonal A/H1N1 isolates of the 2009 season (n = 33) | 541.9±73.17 | 0.36±0.2 | 33.1±8.1 | 1.71±0.31 |
| pH1N1 isolates of the 2009 season (n = 20) | 0.43±0.17 | 0.12±0.04 | 0.08±0.03 | 0.17±0.04 |
| A/Québec/147023/2009-WT (pH1N1) | 0.27±0.01 (1) | 0.18±0.01 (1) | 0.08±0.01 (1) | 0.08±0.004 (1) |
| A/Québec/147365/2009-H274Y (pH1N1) | 423.01±20 (1566) | 0.12±0.01 (0.6) | 11.51±2.7 (144) | 0.28±0.07 (3.5) |
| A/Brisbane/59/2007-WT (seasonal) | 0.53±0.1 (1) | 0.3±0.04 (1) | 0.1±0.03 (1) | 0.32±0.12 (1) |
| A/Brisbane/59/2007-H274Y (seasonal) | 751.12±93 (1417) | 0.5±0.2 (1.7) | 34.5±9.2 (345) | 0.82±0.3 (2.6) |
| Recombinant-WT (pH1N1) | 0.46±0.01 (1) | 0.15±0.01 (1) | 0.09±0.01 (1) | 0.2±0.03 (1) |
| Recombinant-H274Y (pH1N1) | 451.9±26 (982) | 0.14±0.01 (1) | 23.63±5.5 (268) | 0.28±0.01 (1.4) |
a
IC50 values were determined in triplicate experiments. Mean IC50 ± standard deviation (SD) are shown. Fold increases in IC50 values compared to the respective WT virus are shown in parentheses.
Abbreviations: pH1N1, pandemic A/H1N1 virus; WT, wild-type; NA, neuraminidase.