The online version of this article (doi:10.1186/1475-2875-11-92) contains supplementary material, which is available to authorized users.
The authors declare that they have no competing interests.
NT performed experiments, data analysis and paper writing. TT1, MD, LD, BK, JS, MN, MS, JK, FH, TT2 and AK coordination of sampling. KT critically reviewed the manuscript. KT, HE and TM participated in acquisition of funding. TM made substantial contributions to study design, coordination of sampling, data analysis, paper writing and reviewing. All authors have read and approved the final manuscript.
In Plasmodium falciparum, resistance to chloroquine (CQ) is conferred by a K to T mutation at amino acid position 76 (K76T) in the P. falciparum CQ transporter (PfCRT). To date, at least 15 pfcrt genotypes, which are represented by combinations of five amino acids at positions 72-76, have been described in field isolates from various endemic regions. To identify novel mutant pfcrt genotypes and to reveal the genetic relatedness of pfcrt genotypes, a large-scale survey over a wide geographic area was performed.
Sequences for exon 2 in pfcrt, including known polymorphic sites at amino acid positions 72, 74, 75 and 76, were obtained from 256 P. falciparum isolates collected from eight endemic countries in Asia (Bangladesh, Cambodia, Lao P.D.R., the Philippines and Thailand), Melanesia (Papua New Guinea and Vanuatu) and Africa (Ghana). A haplotype network was constructed based on six microsatellite markers located -29 kb to 24 kb from pfcrt in order to examine the genetic relatedness among mutant pfcrt genotypes.
In addition to wild type (CVMNK at positions 72-76), four mutant pfcrt were identified; CVIET, CVIDT, S VMNT and CVMNT (mutated amino acids underlined). Haplotype network revealed that there were only three mutant pfcrt lineages, originating in Indochina, Philippines and Melanesia. Importantly, the Indochina lineage contained two mutant pfcrt genotypes, CVIET (n = 95) and CVIDT (n = 14), indicating that CVIDT shares a common origin with CVIET. Similarly, one major haplotype in the Melanesian lineage contained two pfcrt genotypes; S VMNT (n = 71) and CVMNT (n = 3). In Africa, all mutant pfcrt genotypes were the CVIET of the Indochina lineage, probably resulting from the intercontinental migration of CQ resistance from Southeast Asia.
The number of CQ-mutant lineages observed in this study was identical to that found in previous studies. This supports the hypothesis that the emergence of novel CQ resistance is rare. However, in the mutant pfcrt genotypes, amino acid changes at positions 72, 74 and 75 appear to have recently been generated at least several times, producing distinct pfcrt mutant genotypes. The occurrence of new mutations flanking K76T may yield stronger resistance to CQ and/or a higher fitness than the original pfcrt mutant.
Additional file 1: PCR conditions for genotyping of pfcrt. (XLS 20 KB)12936_2011_2094_MOESM1_ESM.XLS
Additional file 2: PCR conditions for determining variations of six microsatellite loci flanking pfcrt. (XLS 22 KB)12936_2011_2094_MOESM2_ESM.XLS
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Moore DV, Lanier JE: Observations on two Plasmodium falciparum infections with an abnormal response to chloroquine. Am J Trop Med Hyg. 1961, 10: 5-9. PubMed
Meuwissen JH: The use of medicated salt in an antimalaria campaign in West New Guinea. Trop Geogr Med. 1964, 16: 245-255. PubMed
Yung AP, Bennett NM: Chloroquine-resistant falciparum malaria in Papua New Guinea. Med J Australia. 1976, 2: 320-321. PubMed
Ariey F, Fandeur T, Durand R, Randrianarivelojosia M, Jambou R, Legrand E, Ekala MT, Bouchier C, Cojean S, Duchemin JB, Robert V, Le Bras J, Mercereau-Puijalon O: Invasion of Africa by a single pfcrt allele of South East Asian type. Malar J. 2006, 5: 34-10.1186/1475-2875-5-34. PubMedCentralCrossRefPubMed
Fidock DA, Nomura T, Talley AK, Cooper RA, Dzekunov SM, Ferdig MT, Ursos LM, Sidhu AB, Naude B, Deitsch KW, Su XZ, Wootton JC, Roepe PD, Wellems TE: Mutations in the P. falciparum digestive vacuole transmembrane protein PfCRT and evidence for their role in chloroquine resistance. Mol Cell. 2000, 6: 861-871. 10.1016/S1097-2765(05)00077-8. PubMedCentralCrossRefPubMed
Chen N, Kyle DE, Pasay C, Fowler EV, Baker J, Peters JM, Cheng Q: pfcrt Allelic types with two novel amino acid mutations in chloroquine-resistant Plasmodium falciparum isolates from the Philippines. Antimicrob Agents Chemother. 2003, 47: 3500-3505. 10.1128/AAC.47.11.3500-3505.2003. PubMedCentralCrossRefPubMed
Nagesha HS, Casey GJ, Rieckmann KH, Fryauff DJ, Laksana BS, Reeder JC, Maguire JD, Baird JK: New haplotypes of the Plasmodium falciparum chloroquine resistance transporter ( pfcrt) gene among chloroquine-resistant parasite isolates. Am J Trop Med Hyg. 2003, 68: 398-402. PubMed
Huaman MC, Yoshinaga K, Suryanatha A, Suarsana N, Kanbara H: Polymorphisms in the chloroquine resistance transporter gene in Plasmodium falciparum isolates from Lombok, Indonesia. Am J Trop Med Hyg. 2004, 71: 40-42. PubMed
Lim P, Chy S, Ariey F, Incardona S, Chim P, Sem R, Denis MB, Hewitt S, Hoyer S, Socheat D, Mercereau-Puijalon O, Fandeur T: pfcrt polymorphism and chloroquine resistance in Plasmodium falciparum strains isolated in Cambodia. Antimicrob Agents Chemother. 2003, 47: 87-94. 10.1128/AAC.47.1.87-94.2003. PubMedCentralCrossRefPubMed
Mita T, Kaneko A, Lum JK, Bwijo B, Takechi M, Zungu IL, Tsukahara T, Tanabe K, Kobayakawa T, Bjorkman A: Recovery of chloroquine sensitivity and low prevalence of the Plasmodium falciparum chloroquine resistance transporter gene mutation K76T following the discontinuance of chloroquine use in Malawi. Am J Trop Med Hyg. 2003, 68: 413-415. PubMed
Mita T, Kaneko A, Lum JK, Zungu IL, Tsukahara T, Eto H, Kobayakawa T, Bjorkman A, Tanabe K: Expansion of wild type allele rather than back mutation in pfcrt explains the recent recovery of chloroquine sensitivity of Plasmodium falciparum in Malawi. Mol Biochem Parasitol. 2004, 135: 159-163. 10.1016/j.molbiopara.2004.01.011. CrossRefPubMed
Mita T, Kaneko A, Hombhanje F, Hwaihwanje I, Takahashi N, Osawa H, Tsukahara T, Masta A, Lum JK, Kobayakawa T, Ishizaki T, Björkman A: Role of pfmdr1 mutations on chloroquine resistance in Plasmodium falciparum isolates with pfcrt K76T from Papua New Guinea. Acta Trop. 2006, 98: 137-144. 10.1016/j.actatropica.2006.03.002. CrossRefPubMed
Mehlotra RK, Mattera G, Bockarie MJ, Maguire JD, Baird JK, Sharma YD, Alifrangis M, Dorsey G, Rosenthal PJ, Fryauff DJ, Kazura JW, Stoneking M, Zimmerman PA: Discordant patterns of genetic variation at two chloroquine resistance loci in worldwide populations of the malaria parasite Plasmodium falciparu. Antimicrob Agents Chemother. 2008, 52: 2212-2222. 10.1128/AAC.00089-08. PubMedCentralCrossRefPubMed
- Large-scale survey for novel genotypes of Plasmodium falciparum chloroquine-resistance gene pfcrt
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