Evolution of primary HIV drug resistance in a subtype C dominated epidemic in Mozambique

Abstract

Objective: In Mozambique, highly active antiretroviral treatment (HAART) was introduced in 2004 followed by decentralization and expansion, resulting in a more than 20-fold increase in coverage by 2009. Implementation of HIV drug resistance threshold surveys (HIVDR-TS) is crucial in order to monitor the emergence of transmitted viral resistance, and to produce evidence-based recommendations to support antiretroviral (ARV) policy in Mozambique.

Methods: World Health Organization (WHO) methodology was used to evaluate transmitted drug resistance (TDR) in newly diagnosed HIV-1 infected pregnant women attending ante-natal clinics in Maputo and Beira to non-nucleoside reverse transcriptase inhibitors (NNRTI), nucleoside reverse transcriptase inhibitors (NRTI) and protease inhibitors (PI). Subtypes were assigned using REGA HIV-1 subtyping tool and phylogenetic trees constructed using MEGA version 5.

Results: Although mutations associated with resistance to all three drug were detected in these surveys, transmitted resistance was analyzed and classified as <5% in Maputo in both surveys for all three drug classes. Transmitted resistance to NNRTI in Beira in 2009 was classified between 5-15%, an increase from 2007 when no NNRTI mutations were found. All sequences clustered with subtype C.

Conclusions: Our results show that the epidemic is dominated by subtype C, where the first-line option based on two NRTI and one NNRTI is still effective for treatment of HIV infection, but intermediate levels of TDR found in Beira reinforce the need for constant evaluation with continuing treatment expansion in Mozambique.

Figure 1. Distribution of PI secondary mutations in 112 specimens collected in Maputo and Beira in 2009.

Figure 2. Distribution of NNRTI (etravirine) secondary mutations in 112 specimens collected in Maputo and Beira in 2009.

Figure 3. Phylogenetic tree depicting HIV sequences from Beira analyzed in 2009 TDR threshold survey.

Tree was constructed bases on complete sequences of protease and part of RT gene (1.317 bp), using Kimura 2-parameter (K2P) model of base substitution with bootstrap analysis (100 replications) in MEGA 5.05. Nomenclature of samples herein characterized is as follows: MZ (country) and year of sequencing-patient code-region of isolation [BEI: Ponta Gea Health Center and Chingussura Health Center]. Tree includes sequences of the HIV-1 subtypes inferred through REGA (empty circles) along with previously described subtype C in the region, India and Brazil (full circles), other subtypes (other full shapes) and outlier group CPZ, obtained from Los Alamos HIV Sequence Database Subtype Reference Alignments (http: //www.hiv.lanl.gov/content/index).

Figure 4. Phylogenetic tree depicting HIV sequences from Maputo analyzed in 2009 TDR threshold survey.

Tree was constructed bases on complete sequences of protease and part of RT gene (1.317 bp), using Kimura 2-parameter (K2P) model of base substitution with bootstrap analysis (100 replications) in MEGA 5.05. Nomenclature of samples herein characterized is as follows: MZ (country) and year of sequencing-patient code-region of isolation [CID: Jose Macamo Health Center and 1° de Junho Health Center]. Tree includes sequences of the HIV-1 subtypes inferred through REGA (empty circles) along with previously described subtype C in the region, India and Brazil (full circles), other subtypes (other full shapes) and outlier group CPZ, obtained from Los Alamos HIV Sequence Database Subtype Reference Alignments (http: //www.hiv.lanl.gov/content/index).