Assessing subtype and drug-resistance-associated mutations among antiretroviral-treated HIV-infected patients

Background: Several studies have reported an increasing number of therapeutic failures with antiretroviral drugs in HIV-infected patients. The emergence of viral-resistant strains is a major problem for the medical management of infected individuals. The aim of this study is to determine viral subtypes and drug-resistance mutations among antiretroviral-treated HIV-infected patients. Methods: A total of 42 antiretroviral-treated but still viremic HIV-infected patients were enrolled. The HIV pol regions were amplified and sequenced to determine subtypes and antiretroviral-resistant mutations. Results: The subtype distribution was 48% A/D recombinants, 43% subtype B, 5% subtype A and 5% CRF01-AE recombinants. Drug-resistant mutations were most common in subtype B (53%) and A/D recombinant strains (44%). Virus samples from 19% of participants had no drug-resistant mutations; 2, 2 and 76% of samples carried one, two and at least three drug-resistant mutations, respectively. The prevalence of nucleoside transcriptase inhibitor mutations was 76%, with M184V and L74V present in 60 and 38% of samples, respectively. The prevalence of nonnucleoside transcriptase inhibitor mutations was 74%, with P225H present in 55% of study specimens. The prevalence of protease inhibitor mutations was 45%, with major mutation L90M seen in 33% and minor mutation A71V in 36% of samples. Of note, the P225H and A71V are 'minor' drug-resistance mutations conferring only minimal drug-resistance phenotypes in the absence of major mutations. Conclusion: Our study found a high prevalence of drug-resistant mutations in Iranian HIV-infected patients. Our data support the need for continued surveillance of resistance patterns to help guide therapeutic approaches and limit transmission of these variants. (C) 2010 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins