Characterization of Protease Resistance-Associated Mutations in HIV Type 1 Drug-Naive Patients Following the Increasing Prevalence of the CRF02_AG Strain in Morocco

Abstract

The purpose of this study was to investigate the amino acid substitutions in the protease of HIV-1 B and non-B subtypes and evaluate whether the emergence of resistance-associated mutations (RAMs) could have a significant correlation with the increasing prevalence of CRF02_AG strains in Morocco. A total of 162 protease gene sequences were successfully amplified from drug-naive HIV-1-infected individuals. We identified eight (sub)subtypes and CRFs: B(66%), A1(3.7%), C(1.2%), F1(0.6%), F2(0.6%), G(1.2%), CRF02_AG(25.3%), and CRF01_AE(1.2%). Phylogenetic analysis of CRF02_AG strains showed that 9.8% of isolates had a closer connection with reference strains from Morocco and 15.4% clustered with reference strains from eight West African and three European countries. When compared to the B subtype, patients with the CRF02_AG strain had a significantly higher prevalence of mutations associated with resistance to some antiprotease drugs, mainly tipranavir (TPV): H69K (97% vs. 5%; p<0.0001), L89M (95% vs. 1%; p<0.0001), and M36I/L (93% vs. 44%; p<0.0001). Most of the CRF02_AG strains (97%) significantly showed at least two TPV-RAMs (p=0.002) compared to the B subtype (7%). Multivariate analysis revealed that CRF02_AG infection was the only factor highly associated with the occurrence of more than two TPV-RAMs (C=0.42; p<0.0001). These results support the importance of transmitted drug resistance mutations (M36I/L, H69K, and L89M) in the protease gene of HIV-1 CRF02_AG isolates. This HIV drug resistance transmission before protease inhibitor (PI) exposure raises concern about its influence on the susceptibility of CRF02_AG strains to some PIs, especially tipranavir, which will soon be introduced as part of the second line therapeutic regimens in Morocco.