Malaria Journal (Jun 2012)

<it>Ex vivo</it> drug sensitivity profiles of <it>Plasmodium falciparum</it> field isolates from Cambodia and Thailand, 2005 to 2010, determined by a histidine-rich protein-2 assay

  • Tyner Stuart D,
  • Lon Chanthap,
  • Se Youry,
  • Bethell Delia,
  • Socheat Doung,
  • Noedl Harald,
  • Sea Darapiseth,
  • Satimai Wichai,
  • Schaecher Kurt,
  • Rutvisuttinunt Wiriya,
  • Fukuda Mark M,
  • Chaorattanakawee Suwanna,
  • Yingyuen Kritsanai,
  • Sundrakes Siratchana,
  • Chaichana Panjaporn,
  • Saingam Piyaporn,
  • Buathong Nillawan,
  • Sriwichai Sabaithip,
  • Chann Soklyda,
  • Timmermans Ans,
  • Saunders David L,
  • Walsh Douglas S

DOI
https://doi.org/10.1186/1475-2875-11-198
Journal volume & issue
Vol. 11, no. 1
p. 198

Abstract

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Abstract Background In vitro drug susceptibility assay of Plasmodium falciparum field isolates processed “immediate ex vivo” (IEV), without culture adaption, and tested using histidine-rich protein-2 (HRP-2) detection as an assay, is an expedient way to track drug resistance. Methods From 2005 to 2010, a HRP-2 in vitro assay assessed 451 P. falciparum field isolates obtained from subjects with malaria in western and northern Cambodia, and eastern Thailand, processed IEV, for 50% inhibitory concentrations (IC50) against seven anti-malarial drugs, including artesunate (AS), dihydroartemisinin (DHA), and piperaquine. Results In western Cambodia, from 2006 to 2010, geometric mean (GM) IC50 values for chloroquine, mefloquine, quinine, AS, DHA, and lumefantrine increased. In northern Cambodia, from 2009–2010, GM IC50 values for most drugs approximated the highest western Cambodia GM IC50 values in 2009 or 2010. Conclusions Western Cambodia is associated with sustained reductions in anti-malarial drug susceptibility, including the artemisinins, with possible emergence, or spread, to northern Cambodia. This potential public health crisis supports continued in vitro drug IC50 monitoring of P. falciparum isolates at key locations in the region.

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