Low prevalence of transmitted genetic drug resistance in a cohort of HIV infected naïve patients entering antiretroviral treatment programs at two sites in northern South Africa

Abstract

Infection with drug resistant viruses influences the outcome of antiretroviral therapy (ART). This study was carried out to determine the transmitted genetic drug resistance profile in a cohort of patients prior to initiation of treatment at two treatment sites in northern South Africa. These study sites were among the first to benefit from antiretroviral drugs in this region. Data on HIV drug resistance are also limited in northern South Africa; and resistance testing prior to initiation of treatment is not undertaken. In 2008, 80 protease and 80 reverse transcriptase nucleotide sequences obtained from 80 patients were analyzed for genetic drug resistance using the calibrated population resistance tool for transmitted drug resistance. Viral genetic subtypes were determined by phylogenetic analysis. Two drug resistance mutations (M41L and K103N) were detected in two different patients (2.5%; 95% CI: 0.0077-0.0863). Twenty-three sequences (29%) harbored at least one secondary mutation in the reverse transcriptase gene; while all sequences had at least one minor mutation in the protease gene. Phylogenetic analysis of the protease and reverse transcriptase genes showed that 79 out of 80 viruses were HIV-1 subtype C, and one was an A1/C recombinant. The observations suggest that after 4 and 8 years access to ART in Mankweng and the Bela Bela communities respectively, drug resistance mutations in the naïve population was low. Regular studies are needed to update information on drug resistant viruses in treatment naïve patients to inform better treatment policies.