Prevalence of Genotypic Resistance to Nucleoside Analogues and Protease Inhibitors in Antiretroviral-Naive HIV Patients in Campania, Italy

Abstract

The aim of our study was to determine the prevalence of genotypic resistance to nucleoside analogues and protease inhibitors before and after 1997, the year of introduction of Highly Active Antiretroviral Therapy (HAART) in Campania (Italy). Forty-eight plasma HIV-RNA positive patients who had not been previously treated for HIV infection (naïve) were enrolled in two Divisions of Infectious Diseases. The main demographic characteristics were collected for each subject and the primary mutant genotypes were sought only in HIV-RNA positive patients with viral loads higher than 10,000 copies/ml. The diagnosis of HIV infection dated back to before 1996 for 21 out of 48 patients and to after 2000 for the other 27. INNO-Line Probe Assay (LiPA) HIV-RT and INNO-LiPA HIV protease (Innogenetics, Italy) were used to detect mutations conferring resistance to zidovudine, didanosine, zalcitabine, lamivudine, stavudine, saquinavir, indinavir, rotonavir, nelfinavir and amprenavir. No mutations associated with primary resistance to nucleoside analogues and protease inhibitors were detected in the 21 patients who had acquired HIV infection before 1996, whereas one or more mutations were seen in three of the 27 (11.1%) patients with HIV infection diagnosed after 2000. This study confirms that LiPA is a suitable tool for epidemiological surveys of HIV genotypic primary resistance. Drug-resistant HIV-1 genotypes, resistant both to nucleoside analogues and protease inhibitors, were detected only in subjects who had acquired HIV infection after 2000, most of whom had zidovudine-resistant mutants. These data suggest that the introduction of HAART has brought about the circulation ofdrug-resistant HIV genotypes.