Molecular Assessment ofPlasmodium falciparumResistance to Antimalarial Drugs in Papua New Guinea Using an Extended Ligase Detection Reaction Fluorescent Microsphere Assay

Abstract

ABSTRACTSurveillance forPlasmodium falciparumdrug resistance mutations is becoming an established tool for assessing antimalarial treatment effectiveness. We used an extended version of a high-throughput post-PCR multiplexed ligase detection reaction fluorescent microsphere assay (LDR-FMA) to detect single-nucleotideP. falciparumdrug resistance polymorphisms in 402 isolates from children in Papua New Guinea (PNG) participating in an antimalarial treatment trial. There was a fixation ofP. falciparum crt(pfcrt) K76T,pfdhfrC59R and S108N, andpfmdr1mutations (92%, 93%, 95%, and 91%, respectively). Multiple mutations were frequent. Eighty-eight percent of isolates possessed a quintuple mutation (underlined),SVMNT, NRNI, KAA, andYYSND, in codons 72 to 76 forpfcrt; 51, 59, 108, and 164 forpfdhfr; 540, 581, and 613 forpfdhps; and 86, 184, 1034, 1042, and 1246 forpfmdr1, and four of these carried the K540Epfdhpsallele. Thepfmdr1D1246Y mutation was associated with PCR-corrected day 42in vivotreatment failure in children allocated piperaquine-dihydroartemisinin (P= 0.004). Although thepfmdr1NFSDD haplotype was found in only four isolates, it has been associated with artemether-lumefantrine treatment failure in Africa. LDR-FMA allows the large-scale assessment of resistance-associated single-nucleotide polymorphisms (SNPs). Our findings reflect previous heavy 4-aminoquinoline/sulfadoxine-pyrimethamine use in PNG. Since artemether-lumefantrine and piperaquine-dihydroartemisinin will become first- and second-line treatments, respectively, the monitoring ofpfmdr1SNPs appears to be a high priority.