Prevalence of Drug-Resistance-Associated Mutations in Antiretroviral Drug-Naive Zambians Infected with Subtype C HIV-1

Abstract

The ability of HIV-1 to evolve resistance to antiretroviral drugs leads to treatment failure. By nucleotide sequencing of HIV-1 subtype B isolates, amino acids responsible for drug resistance have been identified. Less information is available, however, on the extent and distribution of these amino acids in HIV-1 nonsubtype B viruses circulating mainly in developing countries. More HIV-infected patients in the developing world are now using antiretroviral drugs, and hence there is a need to monitor drug resistance mutations in HIV-1 non-subtype B viruses. This study examines the prevalence of drug resistance mutations in 28 antiretroviral drug-naive HIV-1-infected Zambians. HIV-1 proviral DNA was extracted from peripheral blood mononuclear cells. The region encompassing gag p17 to env C2-V3-C3 was amplified by the polymerase chain reaction followed by direct sequencing. Sequence analyses for drug resistance-associated mutations in th e protease and reverse transcriptase genes, and HIV-1 subtyping, were done. Overall, 92.8% of the generated sequences were HIV-1 subtype C. The generated sequences revealed only secondary associated, but no primary, drug-resistance mutations The most frequent secondary mutations in the protease and RT genes were, respectively, I93L(91.7%), L89M (79.2%), M3611V (79%, 4.2%), and R211K (70.8%), S48T (62.5%). The atypical residues M41N (3.6%) and D67A (3.6%) were detected in the RT gene. This study reveals many naturally occurring polymorphisms in HIV-1 subtype C isolates from antiretroviral drug-naive individuals. Such polymorphisms could lead to rapid treatment failure and development of drug-resistant HIV-1 mutants in individuals undergoing antiretroviral therapy.

Drug Resistance Mutations in Drug-Naive HIV Type 1 Subtype C-Infected Individuals from Rural Malawi

“…However, minor mutations associated with drug resistance have been reported in HIV-1 subtype C-infected drug-naive patients in a number of African locations including Malawi, and the percentage of drug-naive individuals harboring HIV with DRMs thus far has been shown to vary between 2% and 10%. [3][4][5][6] Further characterization of drug resistance mutations in subtype-C HIV-1 and monitoring for transmission of drugresistant strains are extremely important both given the more recent wide-scale availability of ART in countries in which subtype C is predominant, and as the prevalence of non-B HIV-1 increases in countries in which antiretroviral drugs are widely used.…”

“…Extracted DNA was subjected to nested polymerase chain reaction (PCR) amplification of the HIV-1 PR and RT genes employing the primers previously described. 6 The PCR mixture contained 1.5 mM MgCl 2 , 1.5 units of Taq (Roche Expand High Fidelity PCR system), 0.8 mM each dNTP, and 5 pM primers (Eurofins MWG Operon). The cycling conditions were as follows: ''hotstart'' at 98 8 C for 1 min, primary denaturation at 948C for 2 min followed by 35 cycles with 1 min denaturation at 948C, 1 min annealing at 428C, 4 min extension at 728C, and final extension for 7 min at 728C.…”

Short Communication: Antiretroviral Therapy Resistance Mutations Present in the HIV Type 1 Subtype CpolandenvRegions from Therapy-Naive Patients in Zambia

“…Studies have shown a higher prevalence of naturally occurring ART-resistant subtype C variants in the pol gene of ART-naive patients in southern Africa. 8,9 There is also a higher prevalence of NVP-resistant subtype C strains than other subtypes. 2 Moreover, some of these naturally occurring polymorphisms likely accelerate the emergence of ART resistance.…”

“…For comparison we have also included the ART minor mutations reported by another study conducted during 2000 in Zambia (referred to as the Handema et al cohort). 8 To be consistent in the parameters used for the analysis, PR and RT sequences published in this study (GenBank accession numbers AB081151-AB081175 for protease and AB081176-AB081203 for reverse transcriptase) were analyzed using current drug resistance classification parameters. The prevalence range of the three PR resistance-associated mutations, M36I, H69K, and I93L, was 80-100% in all the three cohorts.…”

Prevalence of drug-resistant mutations in newly diagnosed drug-naïve HIV-1-infected individuals in a treatment site in the Waterberg District, Limpopo province

“…Drug-resistance studies among naïve patients reported a prevalence in Gauteng Province in 2002 and 2004 of 4.2%; 5 in Cape Town of 2.5%; 6 and 3.6% in Free State Province. 7 Low levels (<5%), or the absence of drug-resistant mutations, have been reported in Zambia 8 and Malawi. 9 Higher rates have been reported in several developed countries with more than a decade of ART history.…”