Scale-up of antiretroviral treatment in sub-Saharan Africa is accompanied by increasing HIV-1 drug resistance mutations in drug-naive patients

Objectives: To evaluate the frequency and progression over time of the WHO-defined transmitted HIV-1 drug resistance mutations (DRMs) among antiretroviral treatment (ART)-naive HIV-1-infected patients in Cameroon. Design: We analyzed HIV-1 DRM data generated from 369 ART-naive individuals consecutively recruited between 1996 and 2007 in urban and rural areas in Cameroon. Methods: HIV-1 drug resistance genotyping was performed in the pol gene using plasma samples and surveillance DRMs were identified using the 2009 WHO-DRM list. Results: We observed in Yaounde, the capital city, an increasing prevalence of DRMs over time: 0.0% (none of 61 participants) in 1996-1999; 1.9% (one of 53 participants) in 2001; 4.1% (two of 49 participants) in 2002; and 12.3% (10 of 81 participants) in 2007. In the rural areas with more recently implemented ART programs, we found DRMs in six of 125 (4.8%) ART-naive individuals recruited in 2006-2007. DRMs identified in both areas included resistance mutations to protease inhibitors, nucleoside reverse transcriptase inhibitors (NRTIs) and non-NRTIs (NNRTIs) that might impair the efficacy of available first-line and second-line treatments. Conclusion: This report showed an increase in transmitted DRMs in areas where antiretroviral drugs were introduced earlier, although other factors such as natural viral polymorphisms and acquired DRMs through exposure to antiretroviral cannot be totally excluded. Further surveillances are needed to confirm this evolution and inform public health policies on adequate actions to help limit the selection and transmission of drug-resistant HIV, while scaling up access to ART in developing countries.