Antiretroviral drug resistance in HIV-1 patients on first-line therapy or untreated across five treatment centers in Yaounde's Centre Region, Cameroon

Antiretroviral therapy (ART) improves HIV survival. However, as ART programs expand in resource-limited settings like Cameroon toward UNAIDS 95-95-95 goals, monitoring drug resistance is critical. This study investigated HIV-1 subtypes and resistance mutations in Yaoundé, Cameroon. From 2017 to 2021, 231 HIV-positive individuals (treatment-naïve and ART-experienced patients with virological failure [viral load >1,000 copies/mL]) were enrolled across five clinics. Plasma samples were sequenced for reverse transcriptase (RT) and protease (PR) genes. Participants were predominantly female (67.5%), aged 21–35 years. Over half (58.5%) received ART (median duration: 6 months). High median viral load (536,263 copies/mL) indicated poor suppression. CRF02_AG dominated (64.5%), followed by A1 (11.7%) and G (6.9%). Resistance mutations were detected in 18.2% of ART-experienced and 13.4% of treatment-naïve participants, indicating acquired and transmitted resistance. NNRTI resistance occurred in 6.1% (ART-experienced) and 1.3% (naïve); NRTI mutations were rare (0.4%). Key mutations included M184V (NRTI) and K103N (NNRTI). Protease inhibitor (PI) resistance was prevalent (19.5%), with I54V most common. Notably, PI resistance was detected in treatment-naïve individuals. CRF02_AG dominance and high resistance rates underscore challenges to ART efficacy. Significant PI resistance in untreated patients suggests transmission of resistant strains. These findings highlight urgent needs for enhanced resistance surveillance and optimized ART strategies in Cameroon. Keywords: First-line antiretroviral therapy, HIV-1 drug resistance, viral subtype, transmitted drug resistance, Centre, Transversal study