Resistance to antiretroviral therapy among patients in Uganda

Objective: To characterize HIV-1 phenotypic resistance patterns and genotyp ic mutations among patients taking antiretroviral medications in Uganda. Methods: We reviewed charts and retrieved archived plasma specimens from pa tients at an AIDS specialty center in Uganda where antiretroviral therapy h as been used since 1996. Phenotypic and genotypic resistance testing was do ne on specimens associated with a viral load of 1000 copies/ml. Results: Resistance testing of specimens was completed for 16 patients. Amo ng 11 specimens collected before initiation of antiretroviral therapy, no p henotypic resistance or primary genotypic mutations were found. Among 8 pat ients taking lamivudine, phenotypic resistance was found for 9 (90%) of 10 specimens and was associated with an M184V mutation in all nine cases. Amon g 12 patients taking zidovudine, no phenotypic resistance and few primary m utations were found. For 6 patients who were receiving protease inhibitors, we observed no phenotypic resistance and only one primary genotypic mutati on associated with resistance. Conclusions: The absence of apparent resistance among samples collected bef ore antiretroviral therapy supports the notion that a similar approach to s election of antiretroviral therapy can generally be used against non-B subt ypes. 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 d rug resistance in antiretroviral programs in Africa may be similar to those used in developed settings.