Detection of Neuraminidase Inhibitor Resistant Influenza A/H3N2 Viruses by Nucleotide Sequencing Method

Influenza A viruses are the major cause of epidemics and pandemics worldwide. Many researches are underway in order to prevent and treat. Recently Oseltamivir (Tamiflu), a neuraminidase inhibitor (NAI), has been used for their treatment and prevention. The pitfall of using antiviral drugs is emergence of resistant mutants. Different researches in enzyme active site mutation analysis of NAI resistant mutants revealed that common mutation sites are located at 119, 274, 292 residues. The aim of this study was detection of R292K and H274Y mutations in circulating influenza A/H3N2 viruses by using nucleotide sequencing method. Marials and In order to amplify NA gene mutation sites, we used conventional RT-PCR assay on 50 influenza A/H3N2 isolates and then PCR products were sequenced. Evaluation and analysis of raw data by Bioedit version 7.1.3.0 (2011) software was performed. Evaluation of nucleotide sequences did not show any isolates with R292K and or H274Y mutations and all the examined viruses were sensitive to NAI. The findings of this study demonstrate that circulating A/H3N2 viruses are sensitive to NAI and lack resistant mutation sites. As detection of drug resistant mutants with high sensitivity and specificity is very important for efficient treatment strategies, we suggest nucleotide sequencing as a choice method in laboratories protocol because of its accuracy, capability and high efficiency for monitoring of influenza drug resistant mutants in population.