[Molecular epidemiological survey on HIV-1 among the injecting drug users population in Shenzhen].

Objective: To study the prevalent status of human immunodeficiency virus-1 (HIV-1) subtypes in IDU (injecting drug users) population in Shenzhen and to study their source of infection in order to predict the epidemic trend and evolution.
Methods: 166 HIV-1 positive plasma from the IDUs was collected from 1996 to 2008. HIV-1 env genes were amplified by nested-PCR from RNA. The C2-V3 regions (450 bp) of HIV-1 env were sequenced for analyses. Phylogenetic analyses were performed on the nucleotide sequence data.
Results: Among 166 samples, there were 6 HIV-1 strains including CRF01_AE, CRF08_BC, CRF07_BC 3 circulating recombinant forms (CRFs) and B', C, A1 3 subtypes. Data from the genotype analyses showed that 65.06% (108/166) were CRF01_AE, 19.88% (33/166) were CRF07_BC, 6.02% (10/166) were CRF08_BC, 7.23% (9/166) were subtype B', 0.60% (1/166) were subtype C and 1.20% (2/166) were subtype A1. Phylogenetic tree analysis showed that some of HIV-1 clusters defined in CRF01_AE, CRF07_BC and subtype B' in different time groups. Significant increase of gene distance in CRF01_AE and CRF07_BC strains in the three different periods.
Conclusion: CRF01_AE and CRF07_BC were the major epidemic CRF strains among the IDU population in Shenzhen while the subtype B', C, A1 and CRF08_BC were also circulating in IDU population in this region. The variation of all different subtypes was increasing through these years.