Trends in drug resistance mutations in antiretroviral-naïve intravenous drug users of Rio de Janeiro

Abstract

DNA sequencing of a pol gene fragment from drug-naive injecting drug users samples obtained at two time points of the Brazilian AIDS epidemic (Pre-HAART era: 1994 to early 1997, n ¼ 27; postHAART era: 1999–2001, n ¼ 38) was undertaken to assess HIV-1 antiretroviral drug resistance mutations and subtyping profiles. Genotypic analysis revealed the presence of PR primary L90M, D30N, M46I, and V82A mutations in 7.9% of the postHAART group, and a high frequency of secondary mutations (84.2%). Nucleoside RT-associated mutations were observed in 13.2%. In the preHAART group, a higher frequency of RT mutations was observed (22.2%) and no PR primary mutations were found, in agreement with the introduction of protease inhibitors (PIs) in therapy during the same period. The identification of 7.9% of drug-naive injecting drug users already bearing RT/PR primary resistance mutations in the postHAART era group constitutes a major concern in terms of dissemination of drug resistant viruses. The resistance mutations profile of the individuals may reflect the context of antiretroviral treatment in Brazil at the sample collection periods (1994–1997 and 1999–2001). In spite of the differences observed in the drug resistance profiles, similar frequencies of subtype B (63.0 vs. 73.7%), F (22.2 vs. 10.5%), and recombinant B/F (14.8 vs. 15.8%) viruses were found, respectively, in the pre- and post-HAART groups