Molecular Markers for Sulfadoxine/Pyrimethamine and Chloroquine Resistance in Plasmodium falciparum in Thailand

• Published in: Korean journal of parasitology Vol. 60; no. 2; pp. 109 - 116
• Main Authors: Kuesap, Jiraporn, Suphakhonchuwong, Nutnicha, Kalawong, Lertluk, Khumchum, Natthaya
• Format: Journal Article
• Language: English
• Published: Korea (South) 대한기생충학열대의학회 01.04.2022; The Korean Society for Parasitology and Tropical Medicine
• Subjects: Antimalarials - pharmacology; Antimalarials - therapeutic use; Chloroquine - pharmacology; Chloroquine - therapeutic use; Drug Combinations; Drug Resistance; Humans; Malaria, Falciparum - drug therapy; Malaria, Falciparum - parasitology; Original; Plasmodium falciparum - drug effects; Plasmodium falciparum - genetics; Pyrimethamine - pharmacology; Pyrimethamine - therapeutic use; Sulfadoxine - pharmacology; Sulfadoxine - therapeutic use; Thailand; Thailand; chloroquine-resistant transporter; Plasmodium falciparum; dihydropteroate synthase; dihydrofolate reductase; molecular marker
• ISSN: 0023-4001; 1738-0006; 1738-0006
• DOI: 10.3347/kjp.2022.60.2.109

Drug resistance is an important problem hindering malaria elimination in tropical areas. Point mutations in Plasmodium falciparum dihydrofolate reductase (Pfdhfr) and dihydropteroate synthase (Pfdhps) genes confer resistance to antifolate drug, sulfadoxine-pyrimethamine (SP) while P. falciparum chloroquine-resistant transporter (Pfcrt) genes caused resistance to chloroquine (CQ). Decline in Pfdhfr/Pfdhps and Pfcrt mutations after withdrawal of SP and CQ has been reported. The aim of present study was to investigate the prevalence of Pfdhfr, Pfdhps, and Pfcrt mutation from 2 endemic areas of Thailand. All of 200 blood samples collected from western area (Thai-Myanmar) and southern area (Thai-Malaysian) contained multiple mutations in Pfdhfr and Pfdhps genes. The most prevalent haplotypes for Pfdhfr and Pfdhps were quadruple and double mutations, respectively. The quadruple and triple mutations of Pfdhfr and Pfdhps were common in western samples, whereas low frequency of triple and double mutations was found in southern samples, respectively. The Pfcrt 76T mutation was present in all samples examined. Malaria isolated from 2 different endemic regions of Thailand had high mutation rates in the Pfdhfr, Pfdhps, and Pfcrt genes. These findings highlighted the fixation of mutant alleles causing resistance of SP and CQ in this area. It is necessary to monitor the re-emergence of SP and CQ sensitive parasites in this area.