OBJECTIVETo collect background information on drug-resistant HIV-1 strains in various regions before the start of nation-wide antiretroviral therapy in China.

METHODSTwenty percent of the 2,000 blood samples from antiretroviral therapy naive patients collected for the 2nd national HIV molecular epidemiology survey (NHMES) in 2002 were randomly sampled for this study. The entire protease gene and 20-230 amino acids of the reverse transcriptase gene were amplified by PCR from provirus DNA and sequenced. The results were analyzed with HIV db-Drug Resistance Algorithm and genotypic resistance mutations were determined to particular anti-HIV drugs.

RESULTSTotally 164 protease gene sequences and 138 reverse transcriptase gene sequences were obtained from patients; 0.61% of 164 sequences displayed primary resistance mutations in the protease gene, whereas 99.39% carried 1 or more secondary mutations. Genotypic resistance to at least one nucleoside reverse transcriptase inhibitors (NRTI) was present in 5.80%,and resistance to at least one non-nucleo side reverse transcriptase inhibitors (NNRTI) was present in 1.45% of samples.

CONCLUSIONThe prevalence of genotypic drug resistance is very low in drug-naive HIV infected patients from 21 provinces of China tested in this study. Laboratories participated in the NHMES have organized a network to provide drug resistance monitoring service in the current nation-wide antiviral treatment program in China.