title: Polymorphisms in Pfmdr1, Pfcrt, and Pfnhe1 genes are associated with reduced in vitro activities of quinine in Plasmodium falciparum isolates from western Kenya.
abstract: In combination with antibiotics, quinine is recommended as the second-line treatment for uncomplicated malaria, an alternative first-line treatment for severe malaria, and for treatment of malaria in the first trimester of pregnancy. Quinine has been shown to have frequent clinical failures, and yet the mechanisms of action and resistance have not been fully elucidated. However, resistance is linked to polymorphisms in multiple genes, including multidrug resistance 1 (Pfmdr1), the chloroquine resistance transporter (Pfcrt), and the sodium/hydrogen exchanger gene (Pfnhe1). Here, we investigated the association between in vitro quinine susceptibility and genetic polymorphisms in Pfmdr1codons 86 and 184, Pfcrt codon 76, and Pfnhe1 ms4760 in 88 field isolates from western Kenya. In vitro activity was assessed based on the drug concentration that inhibited 50% of parasite growth (the IC50), and parasite genetic polymorphisms were determined from DNA sequencing. Data revealed there were significant associations between polymorphism in Pfmdr1-86Y, Pfmdr1-184F, or Pfcrt-76T and quinine susceptibility (P < 0.0001 for all three associations). Eighty-two percent of parasites resistant to quinine carried mutant alleles at these codons (Pfmdr1-86Y, Pfmdr1-184F, and Pfcrt-76T), whereas 74% of parasites susceptible to quinine carried the wild-type allele (Pfmdr1-N86, Pfmdr1-Y184, and Pfcrt-K76, respectively). In addition, quinine IC50 values for parasites with Pfnhe1 ms4760 3 DNNND repeats were significantly higher than for those with 1 or 2 repeats (P = 0.033 and P = 0.0043, respectively). Clinical efficacy studies are now required to confirm the validity of these markers and the importance of parasite genetic background.
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya School of Biological/Physical Sciences, Department of Zoology, Maseno University, Maseno, Kenya.
authors.forename: Jelagat
authors.initials: J
authors.lastname: Cheruiyot
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Luicer A
authors.initials: LA
authors.lastname: Ingasia
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya School of Biological/Physical Sciences, Department of Zoology, Maseno University, Maseno, Kenya.
authors.forename: Angela A
authors.initials: AA
authors.lastname: Omondi
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Dennis W
authors.initials: DW
authors.lastname: Juma
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: Opot
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya School of Biological/Physical Sciences, Department of Zoology, Maseno University, Maseno, Kenya.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Ndegwa
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Joan
authors.initials: J
authors.lastname: Mativo
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya School of Biological/Physical Sciences, Department of Zoology, Maseno University, Maseno, Kenya.
authors.forename: Agnes C
authors.initials: AC
authors.lastname: Cheruiyot
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Redemptah
authors.initials: R
authors.lastname: Yeda
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Charles
authors.initials: C
authors.lastname: Okudo
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Peninah
authors.initials: P
authors.lastname: Muiruri
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Ngalah S
authors.initials: NS
authors.lastname: Bidii
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Lorna J
authors.initials: LJ
authors.lastname: Chebon
authors.affiliation: School of Biological/Physical Sciences, Department of Zoology, Maseno University, Maseno, Kenya.
authors.forename: Paul O
authors.initials: PO
authors.lastname: Angienda
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Fredrick L
authors.initials: FL
authors.lastname: Eyase
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Jacob D
authors.initials: JD
authors.lastname: Johnson
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Wallace D
authors.initials: WD
authors.lastname: Bulimo
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Ben
authors.initials: B
authors.lastname: Andagalu
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya.
authors.forename: Hoseah M
authors.initials: HM
authors.lastname: Akala
authors.affiliation: Global Emerging Infections Surveillance Program, United States Army Medical Research Unit-Kenya, Kenya Medical Research Institute-Walter Reed Project, Kisumu and Nairobi, Kenya Edwin.Kamau@us.army.mil.
authors.forename: Edwin
authors.initials: E
authors.lastname: Kamau
mesh_terms: D000483:Alleles; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D016054:DNA, Protozoan / Q000235:genetics; D004351:Drug Resistance / Q000235:genetics*; D017125:Genes, Protozoan / Q000235:genetics* / Q000502:physiology; D005838:Genotype; D006801:Humans; D007630:Kenya; D016778:Malaria, Falciparum / Q000469:parasitology; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000502:physiology; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics* / Q000502:physiology; D021261:Parasitic Sensitivity Tests; D010963:Plasmodium falciparum / Q000187:drug effects*; D011110:Polymorphism, Genetic / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics* / Q000502:physiology; D011803:Quinine / Q000494:pharmacology*; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics* / Q000502:physiology
chemical_list: D000962:Antimalarials; D016054:DNA, Protozoan; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D015800:Protozoan Proteins; D011803:Quinine; D017923:Sodium-Hydrogen Exchangers; C513498:Mdr1 protein, Plasmodium falciparum; C416369:PfCRT protein, Plasmodium falciparum
references.citation: J Infect Dis. 1994 Feb;169(2):467-70
references.pmid: 8106787
references.citation: Parasitology. 1998 Dec;117 ( Pt 6):541-5
references.pmid: 9881378
references.citation: Mol Microbiol. 2004 May;52(4):985-97
references.pmid: 15130119
references.citation: PLoS Pathog. 2010 May 13;6(5):e1000887
references.pmid: 20485514
references.citation: Malar J. 2011 Jun 14;10:164
references.pmid: 21669011
references.citation: J Trop Pediatr. 2005 Feb;51(1):17-24
references.pmid: 15601653
references.citation: Mol Microbiol. 2007 Jan;63(1):270-82
references.pmid: 17163969
references.citation: Antimicrob Agents Chemother. 2010 Aug;54(8):3302-7
references.pmid: 20516285
references.citation: PLoS One. 2013 May 13;8(5):e64299
references.pmid: 23675533
references.citation: Malar J. 2011 Feb 11;10:37
references.pmid: 21314947
references.citation: Trans R Soc Trop Med Hyg. 1996 Mar-Apr;90(2):175-8
references.pmid: 8761582
references.citation: Mol Pharmacol. 2002 Jan;61(1):35-42
references.pmid: 11752204
references.citation: Antimicrob Agents Chemother. 2007 Apr;51(4):1172-8
references.pmid: 17220424
references.citation: Am J Trop Med Hyg. 2010 May;82(5):782-7
references.pmid: 20439955
references.citation: Malar J. 2011 May 24;10:144
references.pmid: 21609473
references.citation: Mol Biochem Parasitol. 2009 Jun;165(2):122-31
references.pmid: 19428659
references.citation: Science. 2002 Oct 4;298(5591):210-3
references.pmid: 12364805
references.citation: Antimicrob Agents Chemother. 2011 Dec;55(12):5834-41
references.pmid: 21947391
references.citation: Trans R Soc Trop Med Hyg. 1994 May-Jun;88(3):324-7
references.pmid: 7974679
references.citation: Southeast Asian J Trop Med Public Health. 1983 Sep;14(3):357-62
references.pmid: 6362017
references.citation: Antimicrob Agents Chemother. 2007 Jun;51(6):1926-33
references.pmid: 17371812
references.citation: Lancet. 2004 Jul 31-Aug 6;364(9432):438-447
references.pmid: 15288742
references.citation: Antimicrob Agents Chemother. 2010 Mar;54(3):1200-6
references.pmid: 20065051
references.citation: Am J Trop Med Hyg. 2007 Sep;77(3):431-7
references.pmid: 17827355
references.citation: Med Trop (Mars). 1996;56(2):141-5
references.pmid: 8926873
references.citation: J Pediatr. 1985 Mar;106(3):506-10
references.pmid: 3882924
references.citation: Trans R Soc Trop Med Hyg. 2008 Apr;102(4):346-51
references.pmid: 18321546
references.citation: Trans R Soc Trop Med Hyg. 1997 Jul-Aug;91(4):462-4
references.pmid: 9373656
references.citation: Nature. 2000 Feb 24;403(6772):906-9
references.pmid: 10706290
references.citation: Mol Microbiol. 2005 Aug;57(4):913-26
references.pmid: 16091034
references.citation: Antimicrob Agents Chemother. 2011 Feb;55(2):615-22
references.pmid: 21078941
references.citation: Am J Trop Med Hyg. 1992 Jan;46(1):1-7
references.pmid: 1536378
references.citation: Antimicrob Agents Chemother. 2008 Jan;52(1):288-98
references.pmid: 17954693
references.citation: Malar J. 2012 Jun 13;11:198
references.pmid: 22694953
references.citation: Euro Surveill. 2002 Jul;7(7):113-8
references.pmid: 12631932
references.citation: Antimicrob Agents Chemother. 2010 Oct;54(10):4306-13
references.pmid: 20643902
references.citation: Antimicrob Agents Chemother. 1998 Mar;42(3):682-6
references.pmid: 9517951
references.citation: Am J Trop Med Hyg. 2007 Feb;76(2):245-50
references.pmid: 17297031
references.citation: Sante. 2008 Jan-Mar;18(1):43-7
references.pmid: 18684691
references.citation: Antimicrob Agents Chemother. 2009 May;53(5):1926-30
references.pmid: 19273668
references.citation: J Infect Dis. 2010 May 15;201(10):1551-60
references.pmid: 20367478
references.citation: Science. 1976 Aug 20;193(4254):673-5
references.pmid: 781840
references.citation: J Infect Dis. 2006 Aug 15;194(4):528-35
references.pmid: 16845638