Volume 18, Number 1—January 2012
Dispatch
Mutations I117V and I117M and Oseltamivir Sensitivity of Pandemic (H1N1) 2009 Viruses
Table 1
NAI sensitivity of naturally occurring pandemic (H1N1) 2009 virus I117V mutant and I117V, I117M, I117V + H275Y, I117M + H275Y, and H275Y reverse genetics variants*
Pandemic (H1N1) 2009 viruses | Mutation | Zanamivir |
Oseltamivir carboxylate |
Peramivir |
|||||
---|---|---|---|---|---|---|---|---|---|
Mean IC50 ± SD, nmol/L | -fold difference† | Mean IC50 ± SD, nmol/L | -fold difference† | Mean IC50 ± SD, nmol/L | -fold difference† | ||||
Mean of NAI-sensitive viruses‡ | – | 0.28 ± 0.15 | – | 0.45 ± 0.35 | – | 0.20 ± 0.10§ | – | ||
A/Perth/504/2010 | I117V | 0.96 ± 0.28 | 3 | 1.63 ± 0.70 | 4 | 0.09 ± 0.01 | 1 | ||
RG-WT | – | 0.24 ± 0.05 | – | 0.30 ± 0.20 | – | 0.09 ± 0.01 | – | ||
RG-I117V | I117V | 0.54 ± 0.12 | 2 | 1.42 ± 0.52 | 5 | 0.08 ± 0.02 | 1 | ||
RG-I117M | I117M | 0.32 ± 0.05 | 1 | 0.31 ± 0.06 | 1 | 0.11 ± 0.01 | 1 | ||
RG-I117V + H275Y | I117V + H275Y | 0.44 ± 0.05 | 2 | 568.84 ± 54.89 | 1,896 | 47.08 ± 32.57 | 523 | ||
RG-I117M + H275Y | I117M + H275Y | 0.29 ± 0.04 | 1 | 163.72 ± 17.76 | 546 | 16.12 ± 0.84 | 179 | ||
RG-H275Y | H275Y | 0.26 ± 0.03 | 1 | 195.02 ± 21.05 | 650 | 19.72 ± 1.42 | 219 |
*NAI, neuraminidase inhibitor; IC50, 50% inhibitory concentration; –, not applicable.
†-fold differences compared with IC50 value of RG-WT, except for A/Perth/504/2010, which was calculated for on the basis of comparison to the mean IC50 of circulating pandemic (H1N1) 2009 viruses.
‡n = 3,334, obtained through World Health Organization Global Influenza Surveillance and Response System, April 2009–June 2011.
§Mean and SD of peramivir IC50 values were based on analysis of 273 isolates. RG strains were derived by using site-directed mutagenesis and reverse genetics. Mean IC50 ± SD values of the A/Perth/504/2010 virus and the RG strains were calculated on the basis of values derived from 3 independent assays.