Comparison of in vitro technlques for the detection of Plasmodium falciparum resistance to drugs

Abstract

Plasmodium falciparumcauses the most severe form of human malaria, resulting in 2.7 million deaths throughout the world last year.The major control for this disease is through chemotherapy but the treatment has been complicated by the emergence of resistance to most of the currently available antimalarials; this situation shows the necessity of mapping resistance and for defining the relationship between drug usage politics and the spread of resistance. In this paper four techniques are compared: a modified radiometric micro-test for detecting resistance to several drugs and the modification made to a test used for establishing chloroquine resistance (Rapid-test) is explained.The use of PCR assays to detect pfmdrl gene polymorphism (P falciparum multidrug resistant gene) associated with chloroquine-resistance and to detect DHFR (dihydrofolate reductase) and DHPS (dihydropteroate synthetase) mutalions related to pyrimethamine and sulfadoxine resistance is also demonstrated. Results suggest that the PCR assay is the most convenient approach. However, the use of the modified microtest for the determination of resistance to the quinine-like antimalarials is recommended because the molecular basis of their resistance to drugs remains unknown.