Molecular diversity and polymerase gene genotypes of HIV-1 among treatment-naïve Cameroonian subjects with advanced disease.

BACKGROUND

The progress of antiretroviral treatment roll-out programs in developing countries requires extensive monitoring of primary drug resistance prior to initiation of therapy. This is particularly relevant for Cameroon where a high HIV diversity has been reported.

OBJECTIVES

To determine HIV diversity in Yaoundé, Cameroon, in a cohort of HIV-infected subjects with advanced disease. To characterize HIV-1 mutations conferring primary drug resistance and to assess primary resistance patterns in the RNase H domain of the reverse transcriptase of these viruses.

STUDY DESIGN

HIV-1 RNA was extracted from plasma of 59 HIV-1 infected, drug-naïve subjects with CD4+ T-cell counts<200/microl. HIV-1 pol (PR, RT and RNase H) regions were sequenced for subtyping and for identifying drug resistance mutations in pol (PR, RT and RNase H).

RESULTS

A complex HIV-1 diversity was seen, with multiple subtypes (A1, A2, C, D, F2, H, group O), CRFs (02_AG, 09_cpx, 11_cpx, 13_cpx, 22_01A1, 30_0206, 43_02G) and URFs. Primary drug resistance was low in PR (2%) and in RT regions (4%). RNase H mutations Q509L and Q547K were found in non-CRF02_AG strains.

CONCLUSIONS

A high HIV-1 diversity was already present in Cameroon in the early 90s, when the subjects were likely infected. Primary HIV-1 drug resistance was low. Occurrence of RNase H mutations with proven phenotypic effect on susceptibility to antiretrovirals encourages further assessment of their impact in treatment outcome in the context of complex HIV genetic diversity and in a subtype-specific fashion.