Subtype CRF01_AE dominate the sexually transmitted human immunodeficiency virus type 1 epidemic in Guangxi, China.

Human immunodeficiency virus type 1 (HIV-1) infection by sexual transmission in Guangxi, China had increased dramatically. However, limited information is available on the genetic characterization of the HIV-1 epidemic. In this study, HIV-1 seropositive drug-naïve patients infected by heterosexual transmission were enrolled. The full length gag and pol genes were sequenced followed by phylogenetic analysis, recombinant analysis and drug resistant analysis. Multiple subtypes were identified, including CRF01_AE (80.1%), CRF07_BC (6.4%), CRF08_BC (10.2%), subtype B (1.7%), and URFs (1.7%). In the phylogenetic tree, two large CRF01_AE clusters were identified. One cluster is originating from Vietnam strains as being reported previously in intravenous drug users. One novel cluster was identified and showed close relationship to strains from Fujian province. Inter-subtype recombination among CRF01_AE, subtype B and C was identified. Low level drug-resistance in drug-naïve heterosexually transmitted infections was found. The results suggested that multiple originating CRF01_AE strains dominated the HIV-1 epidemic in heterosexual transmission in Guangxi province.