Acquired resistance to proguanil in Plasmodium knowlesi

Abstract

(1) A high degree of resistance to proguanil was developed in a strain of P. knowlesi which was subjected to periodic exposure to the drug at varying intervals for one year. (2) The effect was persistent even after 8 months during which time no further proguanil was administered during serial passages. (3) The proguanil-resistant strain was found to be refractory to daraprim and bromoguanide but not so to sulphadiazine, M 3349 nor chloroquin.