Plasmodium falciparum cross-resistance between trimethoprim and pyrimethamine

Trimethoprim-sulfamethoxazole has been recommended as part of the standard package of care for people with HIV and AIDS In Africa. A similar antifolat e combination, sulfadoxine-pyrimethamine, is now the first-line antimalaria l drug in several of the African countries with the highest rates of HIV In fection. We present evidence of Plasmodium falciparum cross-resistance betw een trimethoprim and pyrimethamine at the molecular level. The impact of tr imethoprim-sulfamethoxazole on the efficacy of sulfadoxine-pyrimethamine ne eds to be assessed urgently, and alternative antimalarial treatment should be considered for people on trimethoprim-sulfamethoxazole prophylaxis.