Objective: Determine the pattern of drug resistance among HIV infected drug exposed patients failing therapy in Ouagadougou, Burkina Faso.
Methods: The protease (PR) and reverse transcriptase (RT) of 87 samples from 75 treatment exposed HIV infected patients failing therapy were PCR amplified, sequenced, subtyped and analyzed for the presence of drug resistance mutations.
Results: The most common drugs used were 3TC, AZT (or d4T) and EFV. The dominant subtypes were CRF06_cpx (48%) and CRF02_AG (40%). The prevalence of resistance mutations among patients failing therapy was: PR inhibitors (PI), 40%; non-nucleoside RT-inhibitors (NNRTI), 76% and nucleoside RT-inhibitors (NRTI), 85%. Dominant mutations included M46I (37%), 154V (26%), V82A/T/F (30%) in PR; K103N (44%), G190A/S (16%) and T215F/Y (48%) (NRTIs) in RT. Some resistance mutations, notably D67N/G, K70R and L210W (thymidine analogue mutations-TAMs); K101E, V179E in RT, 154V, V82A/T/F and L90M in PR were significantly higher among CRF06_cpx than CRF02_AG strains (P < 0.05). Although not significant, other TAMs (M41L, T215F/Y, K219Q/E) also occurred more frequently among CRF06_cpx strains as well.
Conclusion: There is a high prevalence of drug resistance mutations among ARV exposed patients in Burkina Faso with an unexpected subtype-specific difference. Validation of this result will require larger sample sizes and in vitro drug susceptibility studies with CRF06_cpx strains.