Point mutations in dihydrofolate reductase and dihydropteroate synthase genes of Plasmodium falciparum isolates from Venezuela.

Published

Journal Article

The present study was designed to characterize mutations in dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) genes of Plasmodium falciparum in the Bolivar region of Venezuela, where high levels of clinical resistance to sulfadoxine-pyrimethamine (SP, Fansidar; F. Hoffman-La Roche, Basel, Switzerland) has been documented. We used a nested mutation-specific polymerase chain reaction and restriction digestion methods to measure 1) the prevalence of DHFR mutations at 16, 50, 51, 59, 108, and 164 codon positions, and 2) the prevalence of mutations in the 436, 437, 581, and 613 codon sites in DHPS gene. In the case of the DHFR gene, of the 54 parasite isolates analyzed, we detected the presence of Asn-108 and Ile-51 in 96% of the isolates and Arg-50 mutation in 64% of the isolates. Each of these mutations has been associated with high level of resistance to pyrimethamine. Only 2 samples (4%) showed the wild type Ser-108 mutation and none showed Thr-108 and Val-16 mutations that are specific for resistance to cycloguanil. In the case of DHPS gene, we found a mutation at position 437 (Gly) in 100% of the isolates and Gly-581 in 96% of the isolates. The simultaneous presence of mutations Asn-108 and Ile-51 in the DHFR gene and Gly-437 and Gly-581 in the DHPS gene in 96% of the samples tested suggested that a cumulative effect of mutations could be the major mechanism conferring high SP resistance in this area.

Full Text

Duke Authors

Cited Authors

  • Urdaneta, L; Plowe, C; Goldman, I; Lal, AA

Published Date

  • September 1999

Published In

Volume / Issue

  • 61 / 3

Start / End Page

  • 457 - 462

PubMed ID

  • 10497990

Pubmed Central ID

  • 10497990

International Standard Serial Number (ISSN)

  • 0002-9637

Digital Object Identifier (DOI)

  • 10.4269/ajtmh.1999.61.457

Language

  • eng

Conference Location

  • United States