tetano
Editor, Senior Moderator
Published ahead of print 11 August 2014, doi: 10.1128/AAC.02956-14 AAC.02956-14
Evolution of oseltamivir resistance mutations in influenza A(H1N1) and A(H3N2) viruses during selection in experimentally-infected mice
Andr?s Pizzorno,
Yacine Abed,
Pier-Luc Plante,
Julie Carbonneau,
Mariana Baz,
Marie-?ve Hamelin,
Jacques Corbeil and
Guy Boivin*
Research Center in Infectious Diseases of the CHU of Qu?bec and Laval University, Qu?bec City, QC, Canada.
ABSTRACT
The evolution of oseltamivir resistance mutations during selection through serial passages in animals is still poorly described. Herein, we assessed the evolution of neuraminidase (NA) and hemagglutinin (HA) genes of influenza A/WSN/33 (H1N1) and A/Victoria/3/75 (H3N2) viruses recovered from lungs of experimentally-infected BALB/c mice receiving suboptimal doses (0.05 and 1 mg/kg/day) of oseltamivir over two generations. Traditional phenotypic and genotypic methods as well as deep sequencing analysis were used to characterize potential selection of mutations and population dynamics of oseltamivir-resistant variants. No oseltamivir-resistance NA or HA changes were detected in the recovered A/WSN/33 viruses. However, we observed a positive selection of the I222T NA substitution in the recovered A/Victoria/3/75 viruses, with a frequency increasing over time and with oseltamivir concentration from 4% in the initial pre-therapy inoculum up to 28% after two lung passages. Although the presence of mixed I222T viral populations in mouse lungs only led to a minimal increase in oseltamivir IC50 values (by a mean of 5.7 fold) compared to that of the baseline virus, the expressed recombinant A/Victoria/3/75 I222T NA protein displayed a 16-fold increase in oseltamivir IC50 level when compared to the recombinant WT. In conclusion, the combination of serial in vivo passages under NAI pressure and temporal deep sequencing analysis enabled, for the first time, the identification and selection of the oseltamivir-resistant I222T NA mutation in an influenza H3N2 virus. Additional in vivo selection experiments with other antivirals and drug combinations would provide important information on the evolution of antiviral resistance in influenza viruses.
http://aac.asm.org/content/early/2014/08/05/AAC.02956-14.abstract
Evolution of oseltamivir resistance mutations in influenza A(H1N1) and A(H3N2) viruses during selection in experimentally-infected mice
Andr?s Pizzorno,
Yacine Abed,
Pier-Luc Plante,
Julie Carbonneau,
Mariana Baz,
Marie-?ve Hamelin,
Jacques Corbeil and
Guy Boivin*
Research Center in Infectious Diseases of the CHU of Qu?bec and Laval University, Qu?bec City, QC, Canada.
ABSTRACT
The evolution of oseltamivir resistance mutations during selection through serial passages in animals is still poorly described. Herein, we assessed the evolution of neuraminidase (NA) and hemagglutinin (HA) genes of influenza A/WSN/33 (H1N1) and A/Victoria/3/75 (H3N2) viruses recovered from lungs of experimentally-infected BALB/c mice receiving suboptimal doses (0.05 and 1 mg/kg/day) of oseltamivir over two generations. Traditional phenotypic and genotypic methods as well as deep sequencing analysis were used to characterize potential selection of mutations and population dynamics of oseltamivir-resistant variants. No oseltamivir-resistance NA or HA changes were detected in the recovered A/WSN/33 viruses. However, we observed a positive selection of the I222T NA substitution in the recovered A/Victoria/3/75 viruses, with a frequency increasing over time and with oseltamivir concentration from 4% in the initial pre-therapy inoculum up to 28% after two lung passages. Although the presence of mixed I222T viral populations in mouse lungs only led to a minimal increase in oseltamivir IC50 values (by a mean of 5.7 fold) compared to that of the baseline virus, the expressed recombinant A/Victoria/3/75 I222T NA protein displayed a 16-fold increase in oseltamivir IC50 level when compared to the recombinant WT. In conclusion, the combination of serial in vivo passages under NAI pressure and temporal deep sequencing analysis enabled, for the first time, the identification and selection of the oseltamivir-resistant I222T NA mutation in an influenza H3N2 virus. Additional in vivo selection experiments with other antivirals and drug combinations would provide important information on the evolution of antiviral resistance in influenza viruses.
http://aac.asm.org/content/early/2014/08/05/AAC.02956-14.abstract