Details

Autor(en) / Beteiligte

• Rutvisuttinunt, Wiriya
• Chaorattanakawee, Suwanna
• Tyner, Stuart D
• Teja-Isavadharm, Paktiya
• Se, Youry
• Yingyuen, Kritsanai
• Chaichana, Panjaporn
• Bethell, Delia
• Walsh, Douglas S
• Lon, Chanthap
• Fukuda, Mark
• Socheat, Duong
• Noedl, Harald
• Schaecher, Kurt
• Saunders, David L

Titel

Optimizing the HRP-2 in vitro malaria drug susceptibility assay using a reference clone to improve comparisons of Plasmodium falciparum field isolates

Ist Teil von

• Malaria journal, 2012-09, Vol.11 (1), p.325-325, Article 325

Ort / Verlag

England: BioMed Central Ltd

Erscheinungsjahr

2012

Link zum Volltext

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Apparent emerging artemisinin-resistant Plasmodium falciparum malaria in Southeast Asia requires development of practical tools to monitor for resistant parasites. Although in vitro anti-malarial susceptibility tests are widely used, uncertainties remain regarding interpretation of P. falciparum field isolate values. Performance parameters of the W2 P. falciparum clone (considered artemisinin "sensitive") were evaluated as a reference for the HRP-2 immediate ex vivo assay. Variability in W2 IC50s was assessed, including intra- and inter-assay variability among and between technicians in multiple experiments, over five freeze-thaw cycles, over five months of continuous culture, and before and after transport of drug-coated plates to remote field sites. Nominal drug plate concentrations of artesunate (AS) and dihydroartemisinin (DHA) were verified by LC-MS analysis. Plasmodium falciparum field isolate IC50s for DHA from subjects in an artemisinin-resistant area in Cambodia were compared with W2 susceptibility. Plate drug concentrations and day-to-day technical assay performance among technicians were important sources of variability for W2 IC50s within and between assays. Freeze-thaw cycles, long-term continuous culture, and transport to and from remote sites had less influence. Despite variability in W2 susceptibility, the median IC50s for DHA for Cambodian field isolates were higher (p <0.0001) than the W2 clone (3.9 nM), both for subjects with expected (less than 72 hours; 6.3 nM) and prolonged (greater or equal to 72 hours; 9.6 nM) parasite clearance times during treatment with artesunate monotherapy. The W2 reference clone improved the interpretability of field isolate susceptibility from the immediate ex vivo HRP-2 assay from areas of artemisinin resistance. Methods to increase the reproducibility of plate coating may improve overall assay interpretability and utility.