Abstract
The use of a combination of three-drug regimen has improved HIV-1 infected patients' life span and quality; however the emergence of drug-resistant strains remains a main problem. Reverse transcriptase inhibitors (RTIs) consist of a main part of highly active anti-retroviral therapy (HAART) regimen. The present study aimed to investigate resistant mutations to RTI drugs in both treatment naïve and under treatment HIV patients in Mashhad city, north-eastern Iran. RNA was extracted from sera of 22 treatment naïve and 22 under treatment patients. The mean age of under treated and treatment naive groups were 38.5±6.7 and 40.8±7.9 respectively. cDNA was synthesized and amplified with Nested PCR assay targeting specific sequences of RT gene. The PCR products were sent for sequencing. Bidirectional sequencing results were analysed using HIV drug resistance database supplied by Stanford University (HIV Drug Resistance Database, https://hivdb.stanford.edu). Among under treatment patients 10 out of 22 (45%) had at least one high-level resistance mutation which was higher than high level resistance mutation rate among treatment naive cases (P<0.01). Detected resistance mutations were as follows: K101E, K103N, K103E, V106M, V108I, E138A, V179T, Y181C, M184V, Y188L, Y188H, Y188F, G190A, L210W, T215F, T215Y, K219Q, and P225H. A high level of resistance mutations to RT inhibitors was observed that causes drug resistance especially against lamivudine (3TC). Such mutations should be considered as probable responsible for therapeutic failure. Serial surveillance studies of circulating drug resistance mutations are recommended.