Genotypic resistance and the treatment of HIV-1 infection in Espirito Santo, Brazil

Before December 1997, in Espirito Santo, Brazil, combination antiretroviral therapy was used without routine virologic or immunologic monitoring. To e xamine consequences of therapy in this setting, clinical information, human immunodeficiency virus type 1 (HIV-1) RNA levels, CD4 cell counts, and pro tease and reverse transcriptase sequences were determined for consecutive H IV-1-infected outpatients. Of 48 treatment-naive individuals, 11 were start ed on therapy for HIV-related symptoms; however, 44 (92%) had an RNA level >20,000 copies/mL, a CD4 cell count <500/mm(3), or symptoms, Eighteen (51%) of 35 patients on therapy had an RNA level >20,000 copies/mL. Nucleoside-r esistance mutations were observed in 21 (68%) of 31 nucleoside-experienced subjects. Protease mutations necessary for high-level protease inhibitor (P I) resistance were present together with permissive mutations in 3 of 10 PI -experienced patients. Inability to identify high-risk individuals and to d etect virologic failure may limit the effectiveness of antiretroviral drug programs and may promote the spread of drug resistance where virologic and immunologic monitoring are not available.