Genetic polymorphisms in the pvdhfr, pvmdr1, and pvdhps genes of Plasmodium vivax in patients at a secondary hospital in South Korea

Background: Plasmodium vivax is a major pathogen that causes malaria in Korea. Several genetic polymorphisms in dihydrofolate reductase (pvdhfr), P. vivax multidrug resistance protein 1 (pvmdr1), and P. vivax hydroxymethylpterin pyrophosphokinase-dihydropteroate synthetase (pvdhps) genes are known to be associated with drug resistance in P. vivax. The objective of this study was to profile the known polymorphisms of P. vivax resistance genes in patients at a secondary hospital in Korea. Methods: A total of 12 patients with confirmed P. vivax infections were enrolled for this study. Sanger sequencing was performed for the pvdhfr, pvmdr1, and pvdhps genes to detect polymorphisms of these drug resistance genes. Results: Each specimen had single or double polymorphism in pvdhfr. One specimen had a polymorphism in pvdhps. However, no specimen had any polymorphisms in pvmdr1. There was no strain with multi-polymorphisms exceeding double polymorphisms, which reported the geographic location of treatment failure. Conclusion: No specimen showed chloroquine-resistance polymorphism in pvmdr1. Treatment with first-line therapy was successful. The prevalence of F57L in pvdhfr was higher than that reported previously. This change must be confirmed by further monitoring and surveillance of the strains with multi-polymorphisms.