Molecular characterization of HIV type 1 in Brazzaville, Republic of Congo, and first data on resistance to antiretroviral drugs.

One hundred patients have been enrolled in the CTA (ambulatory treatment center) of Brazzaville, Republic of Congo, from February to April 2011: 41 naive individuals and 59 patients at failure of first line regimen [two nucleoside reverse transcriptase inhibitors (NRTIs) plus one nonnucleoside reverse transcriptase inhibitor (NNRTI)]. Phylogenetic analysis of HIV-1 isolates allowed identification of subtypes and circulating recombinant forms (CRFs). The drug resistance mutations (DRMs) in reverse transcriptase and protease were analyzed in both subpopulations. Globally, 92 viruses were characterized, exhibiting a high diversity of HIV-1 with a majority of undetermined recombinant forms (URF) followed by CRF02_AG, CRF37_cpx, G, A1, B, D, H, and several other subtypes and CRF: F1, A2, C, CRF13_cpx, CRF11_cpx, CRF20_BG, CRF21_A2D, CRF33_01B G, CRF02_AG, CRF37_cpx, and A1. In naive patients, DRMs were observed with percentages ranging from 4% to 9% depending on drug classes. In treated patients at failure, numerous DRMs could be noted that induce actual or potential resistance to major NRTIs and NNRTIs.