Volume 15, Number 12—December 2009
Dispatch
Oseltamivir-Resistant Influenza A Pandemic (H1N1) 2009 Virus, Hong Kong, China
Honglin Chen, Chung Lam Cheung, Hung Tai, Pengxi Zhao, Jasper F.W. Chan, Vincent C.C. Cheng, Kwok-Hung Chan, and K.Y. Yuen
Table
Quasi-species of 274H and 274 Y pandemic (H1N1) 2009 virus from NPA samples and subsequent virus isolate A/Hong Kong/2369/2009 from MDCK cells conferring resistance to oseltamivir, Hong Kong, China*
| Sample | 274H, no. samples positive/no. tested (%) | 274Y, no. samples positive/no. tested (%) | IC50 for oseltamivir, nM | IC50 for zanamivir, nM |
|---|---|---|---|---|
| NPA | 45/95 (47.37) | 50/95 (52.63) | ND | ND |
| MDCK cell culture | 2/96 (2.08) | 94/96 (97.92) | 197.5 | 0.8 |
*50% inhibitory concentrations (IC50s) for oseltamivir and zanamivir were determined by using NA-Star influenza neuraminidase (NA) inhibitor resistance detection kits (Applied Biosystems, Foster City, CA, USA) according to the manufacturer’s instructions. Ratios of 274H and 274Y were evaluated by cloning neuraminidase (NA) gene PCR products from nasopharyngeal aspirate (NPA) samples or MDCK cell–cultured virus into the TA vector (Invitrogen, Carlsbad, CA, USA) and sequencing clones containing the NA gene. ND, not done.
Page created: December 09, 2010
Page updated: December 09, 2010
Page reviewed: December 09, 2010
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.