Evaluation under field conditions of the colourimetric DELI-microtest for the assessment of Plasmodium falciparum drug resistance.
It has been frequently stressed that improved methods are needed to monitor the fast spread of drug-resistant Plasmodium falciparum parasites in endemic areas. We recently developed a colourimetric microtest, double-site enzyme-linked lactate dehydrogenase enzyme immunodetection assay (DELI), to assess drug resistance in vitro. This method, which proved highly effective under laboratory conditions, was evaluated under field conditions in 2 African areas (in Senegal and Burkina Faso) in 1997 and 1998, respectively. The sensitivities of isolates from symptomatic (n = 50) and asymptomatic individuals (n = 26) infected with P. falciparum were assessed in parallel by the new DELI-microtest and the isotopic-microtest. IC50 values of the isolates determined for chloroquine, quinine, amodiaquine and mefloquine were well correlated (r = 0.79, P < 0.001). The proportions of sensitive and resistant isolates determined using the 2 methods were similar. The DELI-microtest proved to be faster to implement than the isotopic-microtest, easier to perform, and did not require sophisticated equipment. Moreover, a larger number of isolates can be tested since parasitaemias as low as 0.005% could be reliably measured with the DELI-microtest. These initial field studies thus support the value of the DELI-microtest for large-scale drug-sensitivity monitoring.
Biomedical Parasitology Unit, Pasteur Institute, 28 rue du Dr Roux, 75724 Paris, France.
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A
Moreno
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P
Brasseur
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N
Cuzin-Ouattara
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C
Blanc
P
P
Druilhe
D000818:Animals; D003124:Colorimetry / Q000379:methods* / Q000592:standards; D004351:Drug Resistance; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods* / Q000592:standards; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D016778:Malaria, Falciparum / Q000188:drug therapy*; D021261:Parasitic Sensitivity Tests / Q000379:methods / Q000592:standards
D007770:L-Lactate Dehydrogenase