Amino acid mutation in dihydrofolate reductase and dihydropteroate synthetase genes in Hormozgan Province, southern Iran.

Molecular analysis of antifolate resistance-associated genes-dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) of Plasmodium vivax is important in predicting the emergence of drug resistance to sulphadoxine-pyrimethamine (SP). The present study aimed to determine the polymorphism of dhfr and dhps genes in P. vivax field isolates. Samples from 80 microscopically diagnosed vivax malaria cases were collected from endemic areas of malaria in Hormozgan Province of Iran, from June 2010 to November 2015. The two sets of codons at position 33, 57, 58, 117, 173 of dhfr and 382, 383, and 553 of dhps genes were analysed by direct sequencing of PCR products. The majority of the isolates (70%) harboured a wild-type allele for P. vivax dhfr (Pvdhfr) and P. vivax dhps (Pvdhps). Mutations were detected in three codons of Pvdhfr (P33L, S58R and S117N) and single codon in Pvdhps (A383G). Novel mutations that have not been identified previously at codon 459 (D459A) of Pvdhps were also observed. The high prevalence of point mutation as well as the rising triple mutation of Pvdhfr and Pvdhps genotypes necessitate change in programmes and guidelines to eliminate P. vivax in future.