To study the prevalence of drug resistance and genotype testing for HIV drug resistance on HIV/AIDS patients with first-line antiretroviral treatment failure at Dong Da Hospital, Hanoi, Vietnam.

Forty-seven patients in Dong Da Hospital, Hanoi, with confirmation of first-line antiretroviral therapy (ART) failure were enrolled in this study from June 2006 to December 2016. Both the protease and reverse transcriptase genes were amplified and sequenced using Trugene^® HIV-1 Genotyping Kit and OpenGene^® DNA system at the biomolecular laboratory of the National Institute of Hygiene and Epidemiology, Vietnam. The Stanford HIV database algorithm was used for interpretation of resistance data and genotyping.

Drug resistance mutations were 90.7% in patients with first-line treatment failure. Amongst patients with drug resistance mutation, 97.7% resisted to non-nucleoside reverse transcriptase inhibitors (NNRTIs), followed by nucleoside reverse transcriptase inhibitors (NRTIs, 95.3%) and protease inhibitors (PIs, 11.6%). Amongst the genetic mutations resistant to NNRTIs, G190S mutation was the highest (51.2%), K101HQ mutation was 39.5% and Y181I mutation was 34.9%. In genetic mutations to NRTIs, M184V mutation was 88.4%. In thymidine analogue mutations, K70R mutation was the most common (37.2%), followed by D67N, T215F and T69N mutations (27.9%, 27.9% and 25.6%, respectively). In genetic mutations in PIs, M36I and K20R mutations made up 9.3%. In NNRTIs, the prevalence of nevirapine resistance was 55.8%, and that of efavirenz resistance was 4.7%. In NRTIs, the ratio of lamivudine resistance was 93.0%, and that of zidovudine resistance was 9.3%. No lopinavir/ritonavir resistance was recorded.

Drug resistance mutations in patients with first-line ART failure had a high prevalence of NNRTI and NRTI resistance but still susceptible to PIs.