ABSTRACT: HIV type-1 (HIV-1) integrase (IN) inhibitor resistance is the consequence of mutations that are selected in the viral IN gene targeted by antiretroviral drugs, such as raltegravir (RAL) and elvitegravir (EVG). The genetic barrier, defined as the number of viral mutations required to overcome the drug-selective pressure, is one of the important factors in the development of drug resistance. The genetic barrier for IN inhibitor resistance was compared between HIV-1 subtype B and HIV-1 subtype CRF02_AG, which is highly prevalent in West Africa and becoming more frequent in developed countries.
IN nucleotide sequences from 73 HIV-1 subtype B and 77 HIV-1 subtype CRF02_AG antiretroviral-naive patients were examined at 19 IN amino acid positions implicated in RAL and EVG resistance.
The majority (14/19) of the studied positions showed a high degree of conservation of the predominant codon sequences leading to a similar genetic barrier between subtypes B and CRF02_AG. Nevertheless, at positions 140 and 151, the variability between subtypes affected the genetic barrier for the mutations G140C, G140S and V1511 with a higher genetic barrier being calculated for subtype CRF02_AG.
The major IN mutations E92Q, Q148K/R/H, N155H and E157Q (implicated in the resistance of IN inhibitors RAL and EVG) are highly conserved between subtypes B and CRF02_AG and display a similar genetic barrier. However, subtype CRFO2_AG showed a higher genetic barrier to acquire mutations 6140S, 6140C and V1511 as compared with subtype B, which could play a role in the resistance to RAL and/or EV6.
Antiviral therapy 02/2009; 14(1):123-9. · 3.16 Impact Factor
ABSTRACT: Sub-Saharan Africa has seen dramatic increases in the numbers of people treated with antiretroviral therapy (ART). Although standard ART regimens are now universally applied, viral load measurement is not currently part of standard monitoring protocols in sub-Saharan Africa.
We describe the prevalence of inadequate virological response (IVR) to ART (viral load >or= 500 copies/mL) and identify factors associated with this outcome in 606 HIV-positive patients treated for at least 6 months. Recruitment took place in 7 hospitals and community-based sites in Bamako and Ouagadougou, and information was collected using medical charts and interviews.
The overall prevalence of IVR in treatment-naive patients was 12.3% and 24.4% for pretreated patients. There were no differences in rates of IVR according to ART delivery sites and time on treatment. Patients living farther away [odds ratio (OR) = 2.48; 95% confidence interval (CI) 1.40 to 4.39], those on protease inhibitor or nucleoside reverse transcriptase inhibitor regimens (OR = 3.23; 95% CI 1.79 to 5.82) and those reporting treatment interruptions (OR = 2.36; 95% CI 1.35 to 4.15), had increased odds of IVR. Immune suppression (OR = 3.32, 95% CI 1.94 to 5.70) and poor self-rated health (OR = 2.00; 95% CI 1.17 to 3.41) were also associated with IVR.
Sufficient expertise and dedication exist in public hospital and community-based programs to achieve rates of treatment success comparable to better-resourced settings.
JAIDS Journal of Acquired Immune Deficiency Syndromes 08/2008; 48(4):476-84. · 4.43 Impact Factor
ABSTRACT: In a multicentred cohort of patients on antiretroviral therapy (ART) in Burkina Faso and Mali, we analysed the prevalence of HIV drug resistance mutations in patients failing a modified directly observed therapy (mDOT) protocol.
Patients on ART >6 months and with viral load (VL) >500 copies/ml were enrolled in a mDOT protocol. Genotypic resistance testing was performed on pre- and post-mDOT plasma samples of patients who still had VL >500 copies/ml after mDOT.
Eight hundred and one patients from seven sites participated in the study. One hundred and thirteen patients (14.1%) had VL >500 copies/ml. Most patients were treated with lamivudine along with zidovudine or stavudine and efavirenz or nevirapine. Genotypes were available for 46 patients. The predominant HIV-1 subtypes were CRFO2_AG in 26 (56.5%) and AGK/K/AK in 12 (26.1%) patients. The prevalence of drug resistance mutations by class were as follows for nucleoside reverse transcriptase inhibitors: 1841/V (82.6%), 215Y/F (32.6%), 219E/Q (19.6%), 70R (19.6%), 67N (21.7%), 41L (15.2%) and 151M(2.2%). For non-nucleoside reverse transcriptase inhibitors the prevalence was: 103N (50%) and 181C/I (19.6%). Phylogenetic analysis showed that, although the genetic distances were small among isolates, there was no clustering of a particular subtype in a specific region and that the high prevalence of AGK subtype in our drug-resistant population was not due to a circulating resistant strain.
Although CRFO2_AG is the dominant clade in the Burkina Faso/Mali region, isolates with subtype K reverse transcriptase were frequent in our cohort. Drug resistance mutation pathways in subtype K reverse transcriptase need to be further evaluated in a larger cohort of non-B HIV-infected individuals.
Antiviral therapy 01/2008; 13(1):141-8. · 3.16 Impact Factor