Molecular Characterization of HIV-1 Drug Resistance Mutations in Treatment-Experienced Patients on Second-Line Antiretroviral Therapy in Benue State

Antiretroviral therapy (ART) failure in HIV-positive individuals necessitates escalation to second-line regimens, yet the accumulation of drug resistance mutations (DRMs) under treatment pressure may compromise second-line efficacy, particularly in resource-limited settings where viral load monitoring is inconsistent. This study molecularly characterized HIV-1 drug resistance mutations in treatment-experienced patients on second-line protease inhibitor-based ART at the ART program of Benue State University Teaching Hospital, Makurdi, North Central Nigeria. Blood samples were collected from 80 patients with confirmed virological failure (HIV RNA greater than 1000 copies/mL) on second-line ART for at least 12 months. HIV-1 RNA was extracted and the protease (PR), reverse transcriptase (RT), and integrase (IN) genes amplified by RT-PCR. Amplicons were Sanger sequenced and DRMs annotated using the Stanford HIV Drug Resistance Database. Major protease inhibitor DRMs were detected in 52.5% of patients with virological failure, including I54V (34%), V82A (28%), and I84V (21%). NRTI resistance mutations M184V and K65R were present in 71% and 38% of subjects, respectively. INSTI resistance was detected in 8%, though integrase inhibitors were not yet incorporated into second-line regimens at the study site. These findings highlight the urgent need for routine HIV genotypic resistance testing prior to second-line regimen switch decisions in Benue State ART programs. Keywords: HIV-1, drug resistance mutations, second-line ART, Sanger sequencing, Benue State.