Table 1. Susceptibility of I223R mutant and control pandemic (H1N1) 2009 strains to oseltamivir carboxylate in the chemiluminescent NA inhibition assay, Canada, 2010*.
| Virus strain |
NA mutation† |
Susceptibility | ||||
|---|---|---|---|---|---|---|
| OAHPP testing |
|
NML testing |
||||
| Mean IC50 ± SD, nmol |
-fold increase |
Mean IC50 ± SD, nmol |
-fold increase |
|||
| A/Ontario/313762/2009 | I223R | 9.49 ± 2.19‡ | 28 | 10.95 ± 2.5‡ | 22 | |
| A/California/07/2009-like control | Wild type | 0.34 ± 0.14§ | 0.49 ± 0.31§ | |||
| Oseltamivir-resistant control | H275Y | 57.1 ± 21.48¶ | 168 | 81.42 ± 24.1¶ | 166 | |
*NA, neuraminidase; OAHPP, Ontario Agency for Health Protection and Promotion; NML, National Microbiology Laboratory; IC50, 50% inhibitory concentration. †Mutations presented in N1 numbering. ‡For 7 and 4 experiments done by OAHPP and NML, respectively. §For 17 and 1,446 experiments done by OAHPP and NML, respectively. ¶For 13 and 14 experiments done by OAHPP and NML, respectively.