Prevalence of antiretroviral drug resistance in untreated persons newly diagnosed with HIV-1 infection.

Current knowledge of HIV-primary resistance indicates that the prevalence of transmitted resistant strains has increased to substantial levels over the past few years, with a wide variation depending upon a number of factors. New infections with a virus strain already resistant to antiretroviral drugs, namely non-nucleoside reverse transcriptase inhibitor (NNRTI), have a negative impact on initial treatment response and also shorten the time to first virologic failure. The aim of this study was to determine the prevalence of antiretroviral drug resistance by a genotypic test in a population with newly diagnosed HIV-1 infection at a clinical centre in Bologna between June 2006 and September 2007.