Application of drug-resistance genotyping of HIV-1 in investigating HIV drug resistant strains in selected areas of Guangdong Province

Objective To apply HIV-1 genotyping in the surveillance of subjects infected with HIV-1 drug resistant strains,and to investigate if there are drug-resistant HIV-1 strains transmitted among infected subjects before antiretroviral therapy in Guangdong Province.Methods Viral RNA samples were collected from the sera of subjects infected with HIV-1 without receiving HAART intervetion,and were amplified by nested PCR;then the amplified fragments were sequenced and analyzed.Result HIV-1 drug resistance genotyping can be applied in targeted gene fragments obtained from samples in which the viral load is more than 1000 copies/ml and CD_4 is less than 400.Among 50 untreated cases,2 cases had low to median mutations associated with resistance,and the rate was 4%,none of which had high mutations associated with resistance.Two cases had general mutations associated with resistance,with a rate of 4%.Conclusion HIV-1 genotyping is an effective tool for the surveillance of HIV-1 drug resistant strains.These tests are accurate and reliable.The results of the study confirm the hypothesis that there are natural drug resistant mutants in the infected subjects even without receiving antiretroviral regimens.