Geographic distribution of amino acid mutations in DHFR and DHPS in Plasmodium vivax isolates from Lao PDR, India and Colombia.

Naowarat Saralamba,Nicholas P J Day,Mayfong Mayxay,Mallika Imwong,Paul N Newton,Supatchara Nakeesathit,Nicholas J White,Jung-Ryong Kim,Lyda Osorio,Arjen M Dondorp

doi:10.1186/s12936-016-1543-8

Abstract

BackgroundNon-synonymous mutations in dhfr and dhps genes in Plasmodium vivax are associated with sulfadoxine–pyrimethamine (SP) resistance. The present study aimed to assess the prevalence of point mutations in P. vivax dhfr (pvdhfr) and P. vivax dhps (pvdhps) genes in three countries: Lao PDR, India and Colombia.MethodsSamples from 203 microscopically diagnosed vivax malaria were collected from the three countries. Five codons at positions 13, 57, 58, 61, and 117 of pvdhfr and two codons at positions 383 and 553 of pvdhps were examined by polymerase chain reaction-restriction fragment length polymorphism methodology.ResultsThe largest number of 58R/117 N double mutations in pvdhfr was observed in Colombia (94.3 %), while the corresponding wild-type amino acids were found at high frequencies in Lao PDR during 2001–2004 (57.8 %). Size polymorphism analysis of the tandem repeats within pvdhfr revealed that 74.3 % of all the isolates carried the type B variant. Eighty-nine per cent of all the isolates examined carried wild-type pvdhps A383 and A553.ConclusionsAlthough SP is not generally used to treat P. vivax infections, mutations in dhfr and dhps that confer antifolate resistance in P. vivax are common. The data strongly suggest that, when used primarily to treat falciparum malaria, SP can exert a substantial selective pressure on P. vivax populations, and this can lead to point mutations in dhfr and dhps. Accurate data on the global geographic distribution of dhfr and dhps genotypes should help to inform anti-malarial drug-use policies.

Highlights

Non-synonymous mutations in dhfr and dhps genes in Plasmodium vivax are associated with sulfadox‐ ine–pyrimethamine (SP) resistance
Mixed infections were present at high frequency in Lao PDR (2001–2004, eight out of 98 samples), while in India mixed infections accounted for one of 32 samples, and there were no mixed infections in the 28 Colombian samples
Genotype polymorphisms within Plasmodium vivax DHFR (PvDHFR) were examined in five codons at positions 13, 57, 58, 61, and 117 (Fig. 1)

Summary

Introduction

Non-synonymous mutations in dhfr and dhps genes in Plasmodium vivax are associated with sulfadox‐ ine–pyrimethamine (SP) resistance. The present study aimed to assess the prevalence of point mutations in P. vivax dhfr (pvdhfr) and P. vivax dhps (pvdhps) genes in three countries: Lao PDR, India and Colombia. Molecular epidemiology studies have revealed that the point mutations in the malaria parasite’s dhfr and dhps genes, which confer resistance to SP, change the amino acid residues around the active sites of the Saralamba et al Malar J (2016) 15:484. Point mutations in PfDHPS codons 436, 437, 540, 581, and 613 have been found to be associated with sulfadoxine resistance [11], and in P. vivax homologous PvDHPS mutations have been described at codons 382, 383, 512, 553, and 585. The well-described patterns of mutations related to drug resistance in P. falciparum and P. vivax have led to the development of the polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP) technique as a molecular surveillance tool for predicting SP drug resistance in specific geographical areas

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