title: Mutations in Plasmodium falciparum dihydrofolate reductase and dihydropteroate synthase and epidemiologic patterns of pyrimethamine-sulfadoxine use and resistance.
abstract: To assess the relationship between mutations in Plasmodium falciparum dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) and clinical pyrimethamine-sulfadoxine resistance, polymerase chain reaction surveys and analyses for new mutations were conducted in four countries with increasing levels of pyrimethamine-sulfadoxine resistance: Mali, Kenya, Malawi, and Bolivia. Prevalence of mutations at DHFR codon 108 and a new mutation at DHPS 540 correlated with increased pyrimethamine-sulfadoxine resistance (P < .05). Mutations at DHFR 51, DHFR 59, and DHPS 437 correlated with resistance without achieving statistical significance. Mutations at DHFR 164 and DHPS 581 were common in Bolivia, where pyrimethamine-sulfadoxine resistance is widespread, but absent in African sites. Two new DHFR mutations, a point mutation at codon 50 and an insert at codon 30, were found only in Bolivia. DHFR and DHPS mutations occur in a progressive, stepwise fashion. Identification of specific sets of mutations causing in vivo drug failure may lead to the development of molecular surveillance methods for pyrimethamine-sulfadoxine resistance.
authors.affiliation: Department of Medicine, University of Maryland School of Medicine, Baltimore 21201, USA.
authors.forename: C V
authors.initials: CV
authors.lastname: Plowe
authors.forename: J F
authors.initials: JF
authors.lastname: Cortese
authors.forename: A
authors.initials: A
authors.lastname: Djimde
authors.forename: O C
authors.initials: OC
authors.lastname: Nwanyanwu
authors.forename: W M
authors.initials: WM
authors.lastname: Watkins
authors.forename: P A
authors.initials: PA
authors.lastname: Winstanley
authors.forename: J G
authors.initials: JG
authors.lastname: Estrada-Franco
authors.forename: R E
authors.initials: RE
authors.lastname: Mollinedo
authors.forename: J C
authors.initials: JC
authors.lastname: Avila
authors.forename: J L
authors.initials: JL
authors.lastname: Cespedes
authors.forename: D
authors.initials: D
authors.lastname: Carter
authors.forename: O K
authors.initials: OK
authors.lastname: Doumbo
mesh_terms: D000349:Africa / Q000453:epidemiology; D000595:Amino Acid Sequence; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology / Q000627:therapeutic use*; D001483:Base Sequence; D001838:Bolivia / Q000453:epidemiology; D003001:Cloning, Molecular; D016054:DNA, Protozoan / Q000032:analysis / Q000235:genetics; D004094:Dihydropteroate Synthase / Q000235:genetics* / Q000378:metabolism; D004338:Drug Combinations; D004351:Drug Resistance; D006801:Humans; D016778:Malaria, Falciparum / Q000188:drug therapy / Q000453:epidemiology / Q000235:genetics / Q000469:parasitology*; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016254:Mutagenesis, Insertional; D010963:Plasmodium falciparum / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011739:Pyrimethamine / Q000494:pharmacology / Q000627:therapeutic use*; D013413:Sulfadoxine / Q000494:pharmacology / Q000627:therapeutic use*; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D000962:Antimalarials; D016054:DNA, Protozoan; D004338:Drug Combinations; C001205:fanasil, pyrimethamine drug combination; D013413:Sulfadoxine; D013762:Tetrahydrofolate Dehydrogenase; D004094:Dihydropteroate Synthase; D011739:Pyrimethamine