To characterize HIV-1 phenotypic resistance patterns and genotypic mutations among patients taking antiretroviral medications in Uganda the authors reviewed charts and retrieved archived plasma specimens from patients at an AIDS specialty center where antiretroviral therapy has been used since 1996. Phenotypic and genotypic resistance testing was done on specimens associated with a viral load of 1000 copies/ml. Resistance testing of specimens was completed for 16 patients. Among 11 specimens collected before initiation of antiretroviral therapy no phenotypic resistance or primary genotypic mutations were found. Among 8 patients taking lamivudine phenolytic resistance was found in 9 (90%) of 10 specimens and was associated with an M184V mutation in all 9 cases. Among 12 patients taking zidovudine no phenotypic resistance and few primary mutations were found. For 6 patients who were receiving protease inhibitors the authors observed no phenotypic resistance and only one primary genotypic mutation associated with resistance. The absence of apparent resistance among samples collected before antiretroviral therapy supports the notion that a similar approach to selection of antiretroviral therapy can generally be used against non-B subtypes. A genotypic marker of antiretroviral resistance to lamivudine in HIV-1 subtypes A C and D was similar to those in subtype B infections. These results suggest that the methods used for monitoring for the emergence of drug resistance in antiretroviral programs in Africa may be similar to those used in developed settings. (authors)
