Objective: To evaluate the resistance against the adamantine of multi-genotype (H1N1, H3N2 and H9N2) swine influenza viruses isolated from China in recent years by pyrosequencing.
Methods: Mutation in one of five key amino acid residues (positions 26, 27, 30, 31 and 34) within the M2 protein of influenza A viruses, leading to resistance against the adamantine class of anti-influenza drugs. The residues L26, V27, A30, S31, and G34 in the M2 protein were targeted for pyrosequencing,and 10 swine influenza viruses obtained from China during 2004 to 2008 were used to perform the amantadine resistance analysis.
Results: All 5 H1N1 swine influenza viruses were adamantine resistance, three mutations were founded in these isolates, namely V27T, V27I and S31N. Other five isolates, including four H3N2 and one H9N2 swine influenza virus, were proved to be sensitive to amantadine.
Conclusion: Pyrosequencing technology based on the M2 gene can be used to determine the amantadine resistance for multi-genotype swine influenza viruses.