[Genetic analysis of VP1 sequences of enterovirus 71 isolated from patients of hand, foot and mouth disease in Beijing, 2008].

Objective: To get genetic information of VP1 coding region of HEV71 in Beijing in 2008.

Methods: Enteroviruses were isolated from samples of throat swabs collected from 33 HFMD patients within 3 days after onset by rhabdomyosarcoma(RD) cells and identified by RT-PCR method with specific primers to human enteroviruses, then VP1 coding region was amplified and sequenced by Sanger dideoxy. Bioedit 7.0.5 and MEGA3.1 were used for the nucleotide sequence alignment and phylogenetic analysis.

Results: 16 virus strains were isolated from 33 samples, of which 14 strains were identified as HEV71 and 2 were CVA16, and 1 was co-infected with CVA16 and HEV71. Sequence analysis of VP1 nucleotide sequences of 10 HEV71 isolates showed that homologous analysis of nucleotide identity amino acid 95.5%-100% and 98.9%-100% respectively; representative strains of Fuyang in 2008, nucleotide identity was 95.4%-99.1%; with representative strain of C4 nucleotide identity was over 92%. Phylogenetic analysis of HEV71 strains for the nucleotide sequence of VP1 coding region clarified that the HEV71 isolates in Beijing belonged to C4a cluster of C4 sub-genotype and 10 strains formed four relatively separated clusters.

Conclusions: The HEV71 viruses isolated from children of HFMD in Beijing belonged to C4 sub-genotype, and C4a cluster which was the predominant in China since 2004. According to phylogenetic analysis, HEV71 which belonged to more than 4 different clusters were circulating in Beijing in 2008. More virological suggestion for disease control and prevention, and information of HEV71 molecular epidemiology need to be collected urgently due to the successive large epidemic of HEV71 in China.