Genetic characterization of HIV-1 strains in Togo reveals a high genetic complexity and genotypic drug-resistance mutations in ARV naive patients.

In this study, the genetic diversity of HIV-1 and the presence of genotypic drug-resistance mutations in ARV naive patients in Lomé, the capital city of Togo, was documented for the first time. Between June 2006 and January 2007, 83 plasma samples were collected in Lomé from HIV-1 positive and antiretroviral (ARV) naive individuals. Pol (protease+RT) and env (V3-V5) regions were amplified and sequenced. Phylogenetic and recombination analyses were done to identify the HIV-1 variants. Pol sequences were then inspected to identify presence of drug-resistance mutations based on the WHO list recommended for epidemiological studies. A total of 75 plasma samples were amplified and sequenced in both genomic regions. The phylogenetic analysis showed that CRF02 (48.7% and 51.2%) and G (12.8% and 16.2%) were predominant, followed by A3 (6.4% and 6.2%) and CRF06 (3.8% and 12.5%) in pol and env, respectively. One strain was identified as CRF05 in pol and env. Two divergent subtype A strains in env were undetermined (U) in pol but clustered with a previously described complex recombinant strain, 99GR303. Overall, at least 23/83 (27.7%) strains were recombinant, 19 had a unique recombinant structure in pol, and 4 had discordant subtype/CRF designations between pol and env. The subtypes/CRFs involved in the recombination events corresponded to those already circulating as non-recombinant strains in the country. A total of 8 patients harbored strains with mutations associated to drug resistance: L90M (n=1), K103N (n=1), T69N (n=1), T215S (n=1), M41L (n=4). In this study we showed the complexity of the HIV-1 strains circulating in Togo and documented a relative high proportion of ARV naive patients with drug-resistance mutations. The high number of resistant strains observed in Togo needs further attention and additional studies are needed to confirm this trend especially because the national ART program experienced major problems to provide drugs on a regular base.