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ObjectiveTo investigate the mutation and genetic evolution of drug resistance gene of A（H1N1） pdm09 influenza pandemic strain in 2023 in Huzhou City， Zhejiang Province. MethodsRespiratory tract specimens from 2 influenza monitoring hospitals were collected forA（H1N1） pdm09 influenza virus nucleic acid detection. Positive specimens were inoculated with MDCK cells for influenza virus isolation and sequencing. DNA Star 7.1 software and Mega 4.0 software were used to analyze the neuraminidase （NA） enzyme active site and the amino acid sites related to drug resistance in M2 protein. ResultsNucleotide homology and amino acid homology of NA between the isolated and the vaccine strains were 98.87%‒99.22% and 98.94%‒99.36%， respectively. The nucleotide homology range of M gene was 99.07% to 99.85%， and the amino acid homology range was 99.02%‒99.94%. The isolates and vaccine strains belong to the evolutionary clades of 6B.1A.5a.2a. The amino acids at the key sites of the enzyme activity center of NA were still highly conserved， and the 9 key amino acid sites related to NA inhibitor resistance did not change， but some mutations occurred at the non-enzyme active sites in some popular strains. The 5 amino acid sites related to drug resistance of M2 protein were not replaced， but the 31st amino acid sites changed from serine to asparagine. ConclusionThe A（H1N1） pdm09 pandemic strain in Huzhou in 2023 has high homology with the 2023‒2024 vaccine strain recommended by WHO. All endemic strains are resistant to amantadines.
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After sequencing, we amplified and cloned foot-and-mouth disease virus (FMDV) O/QYYS/s/06 whole genome by three fragments. These three fragments were cloned into vector P43 one by one to construct recombinant plasmid P43C, which carried the full-length cDNA of FMDV O/QYYS/s/06. Then, plasmid P43C and plasmid T7 expressing T7 RNA polymerase were co-transfected into BHK-21 cells. After 48 h, we harvested the culture broth from transfected BHK-21 cells and inoculated into 2-3 day-old sucking mice. After four generation passage, the virus harvested from sucking mice was confirmed to be type O FMDV by the indirect hemagglutination test, sucking mice's neutralization test and sequencing. The results showed that we have successfully constructed the full-length cDNA clone of FMDV O/QYYS/s/06 strain.