Prevalence of Antiretroviral Drug Resistance and Resistance-Associated Mutations in Antiretroviral Therapy-Naïve HIV-Infected Individuals from 40 United States Cities

AbstractBackground: Transmission of drug-resistant HIV strains to antiretroviral therapy (ART)-naive subjects can negatively impact therapy response. As treatment strategies and utilization of antiretroviral drugs evolve, patterns of transmitted mutations may shift. Method: Paired genotypic and phenotypic susceptibility data were retrospectively analyzed for 317 ART-naive, HIV–infected subjects from 40 small and major metropolitan cities in the Northeastern, Midwestern, Southern, Southwestern, and Northwestern United States during 2003. Results: Using current (January 2007) PhenoSense cutoffs, HIV-from 8% of subjects had reduced susceptibility to ⩾1 drug. By class, >% had reduced susceptibility to protease inhibitors (PIs), and % had reduced susceptibility to nucleoside reverse transcriptase inhibitors (NRTIs); reduced susceptibility to ⩾1 non–nucleoside reverse transcriptase inhibitor (NNRTIs) was seen in 7% of subjects, with 4% of all subjects having reduced susceptibility to all NNRTIs. IAS–USA–defined...