Prevalence of HIV-1 drug resistance among patients failing first-line ART in Monrovia, Liberia: a cross-sectional study.

OBJECTIVES: To assess the prevalence of acquired drug resistance in HIV-1-infected patients living in Monrovia, Liberia, who had clinical and/or immunological failure of first-line ART according to WHO criteria. PATIENTS AND METHODS: Patients receiving ART for >1 year with clinical and/or immunological failure were included. Sequencing of protease and reverse transcriptase regions was performed using Agence Nationale de Recherche sur le SIDA et les hépatites virales (ANRS) procedures and sequences were interpreted using the ANRS resistance algorithm. RESULTS: Ninety patients were enrolled. They had been receiving ART for a median time of 42 months and half were receiving zidovudine/lamivudine/nevirapine. Seventy-five per cent of patients were infected with CRF02_AG. Twenty-seven per cent of patients displayed a plasma viral load <50 copies/mL. Among the 66 patients with detectable viraemia, the median viral load was 4.7 log10 copies/mL (IQR = 3.0-5.6). The prevalence of NRTI and NNRTI resistance-associated mutations (RAMs) was 63% and 71%, respectively; and the median number of NRTI and NNRTI RAMs was 2 and 3, respectively. Two patients (4%) displayed viruses with PI RAMs. Regarding NRTI drug resistance, 29%, 38%, 63%, 29% and 25% of patients had viruses resistant to zidovudine, stavudine, lamivudine/emtricitabine, abacavir and tenofovir, respectively. Regarding the NNRTI drug class, 56%, 65%, 33% and 42% of patients had viruses resistant to efavirenz, nevirapine, etravirine and rilpivirine, respectively. CONCLUSIONS: The high prevalence of acquired drug resistance in patients followed in two centres of the Liberian capital city, documented after a median of 3 years on a first-line ART regimen, jeopardizes the activity of second-line regimens and highlights the need for virological monitoring in these settings.