molecular evaluation of m2 protein of iranian avian influenza viruses of h9n2 subtype in order to find mutations of adamantane drug resistance

Background: the h9n2 subtype of influenza a viruses is considered to be widespread in poultry industry. adamantane is a group of antiviral agents which is effective both in prevention and treatment of influenza a virus infections. these drugs inhibit m2 protein ion channel which has role on viral replication. objectives: the main objective of this study is to evaluate m gene of avian influenza viruses (aivs) of h9n2 subtype in order to find adamantane drug resistance mutations. methods: over 100 suspected samples were collected from different geographical regions of iran during 2012-2013. samples were injected via allantoic sac of 9-11 day-old chicken embryos. a total of 11 out of 100 were aiv. the h9n2 subtype was confirmed by specific rt-pcr. the rt-pcr was conducted for full length m gene. pcr amplified products were purified and then conducted for commercial direct sequencing. finally, sequences were checked for possible sites of adamantane resistance mutations. results: overall, 8 out of 11 viruses harbored the adamantane resistance-associated mutations. of which, four viruses were isolated in 2013 and four viruses in 2012. two different resistance- associated mutations were observed during different years. conclusions: the present study provided clear evidence concerning resistance aivs of h9n2 subtype that were circulating in iranian poultry sector. this concern is always present as m segment might be introduced into human influenza viruses by reassortment phenomenon.