HIV-1 Genetic Diversity and Transmitted Resistance to Integrase Strand Transfer Inhibitors in Benguela, Angola.

Angola is one of the countries with the highest HIV-1 genetic diversity, yet the implications of this diversity for antiretroviral therapy remain insufficiently characterised. Following the introduction of dolutegravir (DTG) in Angola in 2021, evaluating transmitted drug resistance prior to its widespread implementation is essential to inform treatment strategies and establish a baseline for future surveillance. In this study, 243 blood samples were collected from treatment-naïve people living with HIV attending the General Hospital of Benguela, Angola. The integrase coding region of proviral DNA was amplified and sequenced using the Sanger method. Phylogenetic relationships were inferred using a maximum likelihood approach, recombinant forms were characterised by bootscanning analysis, and resistance-associated mutations to integrase strand transfer inhibitors were identified using Stanford HIVdb, ANRS-MIE, and IAS-USA algorithms. A total of 92 integrase sequences were successfully obtained, revealing 16 distinct genetic forms, with unique recombinant forms accounting for 50.0%, followed by subtype C (10.9%) and sub-subtype F1 (8.7%). Five accessory mutations (L74I, L74M, Q95K, T97A, and E157Q) and one major mutation (E92G) were detected, corresponding to an overall prevalence of 28.8% (23/80). These findings highlight the extensive HIV-1 genetic complexity in Angola and support the continued use of DTG-based regimens, while underscoring the importance of sustained surveillance of integrase inhibitor resistance.