Introduction Drug resistance is very serious clinical problem, it is often cause of treatment failure among HIV-positive patients on HAART. Antiretroviral therapy (ART) was started in 2005. The aim of this study is to analyse of the prevalence of drug-resistance mutations (DRMs) within reverse-transcriptase (RT) among HIV-positive on first-line ART.

Methods 205 HIV-positive patients on (AZT/3TC + NVP or EFV) with viral load more than 1500c/ml, and 37 ART-naïve were examined. HIV RNA extraction, RT-PCR and sequencing pol gene were assayed with the kits “ViroSeq HIV-1 genotyping systems” (USA) or “AmpliSens-HIV-genotype” (Russia). Sequencing was performed on ABI3130. To interpret results the programme of the Stanford University (www.hivdb.stanford.edu) was used. HIV subtyping was performed using “REGA HIV-1/2” (www.bioafrica.net), “Comet HIV 1/2” (www.comet.retrovirilogy.lu).

Results Among the received RT sequences HIV-1 subtypes A(A1) (71.1%), CRF02_AG (25.0%), B (2.9%), CRF03_AB (0.5%), cpx06 (0.5%) were identified. Overall, 34.6% (71/205) patients’ treatment failure due to drug-resistance virus. In 22.5% cases were detected drug-resistance mutations (DRMs) to both NRTI and NNRTI. There was no correlation between the formation of drug resistance and the HIV-1 subtype A, B and A/G (35.9%, 33.3% and 37.3%, respectively).

In the NRTI group were identified M184V, T215F, and K219Q mutations. Among DRMs to NNRTI G190A/S, K103N, K101E/H and Y181C/V mutations were registered. Among ART-naïve patients DRMs was not detected.

Conclusion In Kazakhstan the HIV resistance was determined in 3.9% among HAART treated patients and mostly to 3TC, NVP and EFV. It’s necessary to increase the variety of antiretroviral drugs used in the country.