HIV-1 molecular characterization and transmitted drug resistance prevalence among treatment-naïve individuals

Abstract

The distribution of different human immunodeficiency virus type 1 (HIV-1) genotypes and the prevalence of transmitted drug resistance (TDR) mutations vary greatly across different Brazilian regions. This study aimed to describe the HIV-1 molecular diversity and TDR prevalence among treatment-naïve HIV-1 infected individuals in an urban area of Northeastern Brazil. DNA samples from 97 infected individuals were obtained and pol sequences were generated by Polimerase Chain Reaction (PCR) and direct sequencing. Bioinformatics tools were used to identify the presence of associated mutations with drug resistance, to reconstruct the phylogeny and to detect recombination. The median age and estimated time of HIV-1 diagnosis were 34 years and 12 months, respectively and 61% of the patients were male. The main exposure category was sexual (87.5%) and the median TCD4+ lymphocyte counts and viral load were 438 cells/mm3 and 4.4 log10, respectively. The overall TDR prevalence was 5.1% while within each drug class (Non-nucleoside reversetranscriptase inhibitors - NNRTIs, Nucleoside analog reverse-transcriptase inhibitors - NRTIs and Protease inhibitors - PIs) this rate was 2.1% individually. These TDR mutations confer intermediate to high-level resistance to different drugs that are used as first-line treatment options, which reinforce the importance of genotype testing prior to treatment initia-tion. Phylogenetic analysis showed that 73.2% of the samples were subtype B, 14.4% were subtype F, 4.1% were subtype C and 8.3% were BF recombinants. Our data indicate that the genotypic profile of HIV-1 strains circulating in Bahia is diversified and show an increase of subtype C prevalence in Northeast Brazil.