Abstract: Objective To investigate the molecular epidemiology of human immunodeficiency virus 1(HIV-1) infection among men who have sex with men(MSM) in Beijing and survey the up to date HIV-1 prevalence in this region. Methods Seventeen anti-HIV-1 positive samples of MSMs from 2007 2008 were collected, the genomic DNA were isolated directly from the whole blood, HIV-1 gag/env genes were amplified by nested PCR from the genomie of MSMs. The c2-v5 region of env gene and p17-p24 region of gag gene were sequenced for analyzing the subtype directly. Phylogenetic analyses were performed based on the nucleotide sequence data. Results There were three HIV-1 strains including CRF01-AE, B and CRF07-BC among seventeen MSMs in Beijing, genotyping showed that 52.94%(9/17) were CRF01-AE, 29.41%(5/17) were B and 17.65%(3/17) were CRF07-BC. Conclusion There are three HIV-1 subtypes among MSMs in Beijing from the small samples epidemiologic survey, and the CRF01-AE has replaced the B and became the most prevalent HIV-1 subtype in Beijing, and the CRF07-BC is increasing fast among MSMs in Beijing recently.

Key words: men who have sex with men, human immunodeficiency virus 1, subtype, phylogenetic analysis of gene