Surveillance of HIV-1 Antiretroviral Drug Resistant Strains in Thailand in 2009

Abstract

In this study, surveillance of HIV-1 antiretroviral drug resistant strain was conducted on 398 HIV infected/AIDS patients receiving ART for more than 6 months and 96 ART-naïve patients recruited from 21 provinces in all parts of Thailand. Most of the ART treated patients were treated with GPO-VIR (61.17%). All 495 patients were assessed for plasma HIV-1 viral load level and 124 patients (31 treated and 93 ART-naïve) showed HIV-1 viral load > 1,000 copies/ml that were further analyzed for HIV-1 antiretrovral drug resistance by genotyping assay. In ART-experienced group, 21 patients, the highest frequency of NRTIs resistant mutations was M184V/I (81.0%) that associated with resistance to 3TC/FTC in 17 patients. Thymidine analogue-associated mutations (TAMs) were M41L (14.3%), D67N (28.6%), K70R (9.5%), L210W (0%), T215Y/F (52.4%) and K219R (33.3%). Mutations that associated with NNRTIs resistance were A98G (9.5%), K101Q/E (9.5%), K103N (23.8%), V108I (4.8%), Y181C/I (52.4%) and G190A/S (33.3%) and resistance to NVP and EFV were found in 20 and 10 patients respectively. PIs-associated mutations were found in all 21 ART experienced patients but only 2 patients were resistant to PIs (one resist to IDV and APV/FPV and another one resist to SQV/r). In ART- na?ve group, 91 patients, the frequency of NRTIs and NNTIs resistant mutations were only 1.1-3.3% that associated with resistance to 3TC/FTC, NVP and EFV in 1, 5 and 3 patients respectively. Only one na?ve patient had PIsassociated mutations that associated with resistance to IDV and APV/FPV. In conclusion, the percentage of HIV-1 antiretroviral drug resistant strains was 5.3 % (21/398) in ART-experienced group with highest rate of 9.1% (7/77) in patients treated for >6 months-1 year while 6.25% (6/96) was found in ARTnaïve group.