Volume 77, Issue 2
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


pyrimethamine response of isolates and dihydrofolate reductase () gene sequences were analyzed in 2004–2005 and compared with our previous data. Most isolates (n = 103, all mutants) had 50% inhibitory concentrations (ICs) ≥ 119 nM, and six isolates had low ICs (five wild-type or mixed , 0.04–1.37 nM; one triple mutant, 6.4 nM). Of 194 isolates, only 7 had the wild-type and 187 were mutants. The results of the two methods were highly concordant and indicated a significant increase ( < 0.05) in the prevalence of mutant, pyrimethamine-resistant between 1994 and 2005. The addition of probenecid or sulfinpyrazone to pyrimethamine resulted in a slight-to-moderate decrease in the level of pyrimethamine resistance without rendering the parasites susceptible to pyrimethamine. Analysis of molecular markers may be useful for the long-term surveillance of antifolate-resistant malaria.


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  • Received : 03 Sep 2006
  • Accepted : 24 Apr 2007

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