HIV-1 genetic diversity, geographical linkages and antiretroviral drug resistance among individuals from Pakistan.

Abstract

Worldwide antiretroviral therapy (ART) has reduced the mortality and morbidity rates in individuals with HIV infection. However, the increasing occurrence of drug resistance is limiting treatment options. In recent years, Pakistan has witnessed a concentrated epidemic of HIV. It is very important to identify geographical linkages and mutations that generate selective pressure and drive resistance of HIV in our population. The aim of this work was to identify genetic diversity and drug resistance patterns of HIV in Pakistan, using available sequences and bioinformatics tools, which may help in selecting effective combination of available drugs. A total of 755 Pakistani HIV gag, pol and env sequences were retrieved from the Los Alamos HIV database. Sequences were aligned with reference sequences of different subtypes. For geographical linkages, sequences of predominant subtypes were aligned with sequences of the same subtypes from different countries. Phylogenetic trees were constructed using the maximum-likelihood method in MEGA 7 software. For drug resistance analysis, sequences were entered into the Stanford University HIV Drug Resistance Database. Phylogenetic trees for studying genetic diversity showed that 82% of the sequences were of subtype A, while the rest of the sequences were of subtypes B (9.5%), K (2%), D (2%) and AE (1%). Moreover, trees that were constructed to examine geographical linkages showed close clustering of strains with those of the neighboring countries Afghanistan and India, as well as some African countries. A search for drug resistance mutations showed that 93% of the sequences had no major or minor mutations. The remaining 7% of the sequences contained a major mutation, Y115F, which causes the virus to exhibit low to intermediate resistance against lamivudine and emtricitabine. Our data indicate that HIV subtype A is the major subtype, while subtypes K, D and AE are also present in our country, suggesting gradual viral evolution and possible entry of different subtypes from neighboring countries. These data suggest that HIV is still sensitive to most of the antiretroviral drugs used in Pakistan.