title: Genotypes and in vivo resistance of Plasmodium falciparum isolates in an endemic region of Iran.
abstract: Mutations in the dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) genes of Plasmodium falciparum have been correlated with and used to detect antifolate treatment failure, such as sulfadoxine-pyrimethamine (SP), in regions endemic for malaria. To determine the association between molecular markers of SP resistance and in vivo drug resistance, a quick and simple technique that detects single nucleotide polymorphisms in the DHFR and DHPS genes, using PCR-ELISA and sequence-specific oligonucleotide probes, was applied to 53 isolates obtained from an in vivo study in Sistan and Baluchistan Province, in southeastern Iran. Overall, 11.3% of these isolates were obtained from patients with SP treatment failure. Four DHFR polymorphisms (codons 51, 59, 108, and 164) and five DHPS polymorphisms (codons 436, 437, 540, 581, and 613) were investigated. Mutations DHFR Asn-108, DHFR Arg-59, and DHPS 436-Ala/Phe were very common (100, 81.1, and 85%, respectively). Plasmodium falciparum was isolated from 96% of patients with at least two DHFR/DHPS mutations. All resistant isolates had at least three mutations. The high prevalence of mutation associated with antifolate resistance may point toward low drug efficacy in the future.
authors.affiliation: Department of Medical Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Aliehsan
authors.initials: A
authors.lastname: Heidari
authors.forename: Sabine
authors.initials: S
authors.lastname: Dittrich
authors.forename: Tomas
authors.initials: T
authors.lastname: Jelinek
authors.forename: Azarmidokht
authors.initials: A
authors.lastname: Kheirandish
authors.forename: Kambiz
authors.initials: K
authors.lastname: Banihashemi
authors.forename: Hossein
authors.initials: H
authors.lastname: Keshavarz
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D004094:Dihydropteroate Synthase / Q000235:genetics; D004351:Drug Resistance / Q000235:genetics; D005838:Genotype; D006801:Humans; D007492:Iran / Q000453:epidemiology; D016778:Malaria, Falciparum / Q000453:epidemiology* / Q000469:parasitology; D008875:Middle Aged; D009154:Mutation; D018512:Parasitemia; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000235:genetics*; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics
chemical_list: D000962:Antimalarials; D013762:Tetrahydrofolate Dehydrogenase; D004094:Dihydropteroate Synthase