Prevalence of primary HIV drug resistance among seroconverters during an explosive outbreak of HIV infection among injecting drug users

Objectives: This study examined the frequency of transmission of drug resis tant HIV in the population of injecting drug users (IDU) in Vancouver, Cana da during a period of particularly high virus transmission. Design: All subjects enrolled in the Vancouver Injection Drug Users Study w ho seroconverted from HIV negative to positive status (n = 61) between Dece mber 1996 and February 1998 were eligible for analysis. The first seroposit ive sample from 57 individuals with plasma samples available was analyzed f or resistance to antiretroviral agents by population based sequencing of th e HIV protease and reverse transcriptase genes. Methods: Plasma viral RNA was extracted and the viral reverse transcriptase and protease regions were amplified by nested reverse transcription-PCR. T he presence of mutations associated with antiretroviral drug resistance was assessed by automated sequence analysis. Results: Protease and reverse transcriptase sequences were successfully obt ained from the 57 recent seroconverters. No cases of transmission of varian ts associated with significant resistance to protease inhibitors or nucleos ide and non-nucleosides reverse transcriptase inhibitors were detected. Conclusion: The frequency of transmission of drug resistant HIV amongst the se recently infected IDU is extremely low, with no protease or reverse tran scriptase inhibitor resistant strains detected soon after seroconversion. T he data provide no rationale for withholding treatment from this already ma rginalized population. (C) 1999 Lippincott Williams & Wilkins.