Molecular Characterization and Phylogenetic Analysis of Neuraminidase Gene in A/H1N1 Influenza Virus Isolates Circulating in Iran, 2014-2015.

Objectives: Influenza is one of the most important emerging and reemerging infectious diseases in the world. The aim of this study is molecular and phylogenetic analyses of the variations in circulating influenza A/H1N1 virus isolates during 2014-2015 in Iran and investigate on the drug resistance conditions in the related Iranian isolates. Material and Methods: Throat samples from Iranian patients with acute respiratory tract infection were subjected for typing and subtyping by multiplex real-time RT–PCR. Seven positive samples were randomly selected and full-length amplification of Neuraminidase gene (NA) were carried out by RT-PCR. The related amplicons were sequenced and analyzed by bioinformatics software. Results: Phylogenetic analysis on the NA gene of the A/H1N1 isolates revealed a high degree of sequence identity with the corresponding NA genes from viruses circulating in the USA, Russian, India, Thailand, and East Asia region. Moreover, the NA sequences showed point mutations N44S, V106I, V241I, N248D, N369K; resulted in increasing of stability and transmission improvement of the viruses [1, 2]. The NA sequences showed a similarity of 98-99% with the reference strain NC_026434.1 /California/2009. 52.5% of mutations were silent. On amino acid level, the dedicated sequence of NA protein showed 97% identity among isolates. Oseltamivir and Zanamivir resistant mutations were not detected in the isolates. Conclusion: Gathering NA sequence data of influenza viruses isolated from Iran and compare it with counterpart data from other geographical regions would be helpful to explain epidemiological rules governing antigenic drift and reveal the antiviral drug (neuraminidase inhibitors) sensitivity of human influenza A (H1N1) viruses.