Analysis of the Plasmodium vivax dihydrofolate reductase–thymidylate synthase gene sequence

Pécoulas, Philippe Eldin de; Basco, Léonardo K.; Tahar, Rachida; Ouatas, Taoufik; Mazabraud, A

doi:10.1016/s0378-1119(98)00118-8

Cited by 64 publications

(47 citation statements)

References 23 publications

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“…Simple and sensitive methods for the detection of these point mutations have been devised for the P. falciparum dhfr and dhps genes (1, 2, 5, 12-14, 17-19, 21, 25, 28). Recently, the gene coding for DHFR-thymidylate synthase of P. vivax has been cloned and sequenced (3). The presence of mutations in the residues of the P. vivax enzyme (at positions 15, 50, 58, 117, and 173) which were predicted by secondary-structure analysis and amino acid homology to correspond to the five key positions on the P. falciparum gene (positions 16, 51, 59, 108, and 164, respectively) was determined for 30 P. vivax isolates of various geographical origins.…”

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confidence: 99%

Association of Genetic Mutations in Plasmodium vivax dhfr with Resistance to Sulfadoxine-Pyrimethamine: Geographical and Clinical Correlates

Imwong

Pukrittakayamee

Looareesuwan

et al. 2001

Antimicrob Agents Chemother

134

155

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Mutations in the Plasmodium falciparum gene (dhfr) encoding dihydrofolate reductase are associated with resistance to antifols. Plasmodium vivax, the more prevalent malaria parasite in Asia and the Americas, is considered antifol resistant. Functional polymorphisms in the dhfr gene of P. vivax (pvdhfr) were assessed by PCR-restriction fragment length polymorphism using blood samples taken from 125 patients with acute vivax malaria from three widely separated locations, Thailand (n ‫؍‬ 100), India (n ‫؍‬ 16), and Madagascar and the Comoros Islands (n ‫؍‬ 9). Upon evaluation of the three important codons (encoding residues 57, 58, and 117) of P. vivax dhfr (pvdhfr), double-or triple-mutation genotypes were found in all but one case from Thailand (99%), in only three cases from India (19%) and in no cases from Madagascar or the Comoros Islands (P < 0.0001). The dhfr PCR products of P. vivax from 32 Thai patients treated with the antifolate sulfadoxinepyrimethamine (S-P) were investigated. All samples showed either double (53%) or triple (47%) mutations. Following treatment, 34% of the patients had early treatment failures and only 10 (31%) of the patients cleared their parasitemias for 28 days. There were no significant differences in cure rates, but parasite reduction ratios at 48 h were significantly lower for patients whose samples showed triple mutations than for those whose samples showed double mutations (P ‫؍‬ 0.01). The three mutations at the pvdhfr codons for residues 57, 58, and 117 are associated with high levels of S-P resistance in P. vivax. These mutations presumably arose from selection pressure.Drugs which inhibit plasmodial folate biosynthesis represent a major component of the antimalarial armamentarium. The sulfonamides and sulfones inhibit dihydropteroate synthase, and pyrimethamine and cycloguanil (the metabolite of proguanil) inhibit dihydrofolate reductase (DHFR). Sequential inhibition results in a synergistic antimalarial effect (6). Unfortunately, resistance to these drugs develops relatively quickly if they are widely used. Although Plasmodium falciparum acquires resistance readily (10, 11), it has been considered that P. vivax is intrinsically resistant to pyrimethamine (27). However, the initial sensitivity of this parasite to proguanil shortly after its initial deployment in peninsular Malaya in 1947 would suggest that acquired resistance is a more likely explanation for treatment failure (11). P. vivax in Thailand is considered highly resistant to sulfadoxine-pyrimethamine (S-P) (15,20).Molecular studies associated with detailed clinical and epidemiological observations of falciparum malaria have demonstrated that the major mechanism of resistance to pyrimethamine and sulfadoxine results from specific point mutations in the parasite's dhfr and dhps genes, respectively (6,8,13,19,23). These mutations result in the nonsynonymous replacement of key amino acid residues and thus a much reduced affinity of the mutant enzyme for the respective drug. Simple and sensitive methods for the detect...

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confidence: 99%

Association of Genetic Mutations in Plasmodium vivax dhfr with Resistance to Sulfadoxine-Pyrimethamine: Geographical and Clinical Correlates

Imwong

Pukrittakayamee

Looareesuwan

et al. 2001

Antimicrob Agents Chemother

134

155

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“…(ARI/Pakistan) which was considered to represent the wildtype sequence (3,4). Two P. vivax isolates, isolates Belem and Sal 1, are established lines originating from Latin America.…”

Section: P Vivax Isolatesmentioning

confidence: 99%

“…In those countries where S-P was used extensively, such as Thailand, high-grade antifolate resistance has also emerged in P. vivax populations (14,21). The P. vivax dhps gene has not been well characterized, but the P. vivax dhfr gene has been (3), and a number of point mutations have been identified in parasites from different origins (4,8).…”

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confidence: 99%

Novel Point Mutations in the Dihydrofolate Reductase Gene of Plasmodium vivax : Evidence for Sequential Selection by Drug Pressure

Imwong

Pukrittayakamee

Rénia

et al. 2003

Antimicrob Agents Chemother

127

146

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Mutations in the dihydrofolate reductase (dhfr) genes of Plasmodium falciparum and P. vivax are associated with resistance to the antifolate antimalarial drugs. P. vivax dhfr sequences were obtained from 55 P. vivax isolates (isolates Belem and Sal 1, which are established lines originating from Latin America, and isolates from patient samples from Thailand [n ‫؍‬ 44], India [n ‫؍‬ 5], Iran [n ‫؍‬ 2], and Madagascar [n ‫؍‬ 2]) by direct sequencing of both strands of the purified PCR product and were compared to the P. vivax dhfr sequence from a P. vivax parasite isolated in Pakistan (isolate ARI/Pakistan), considered to represent the wild-type sequence. In total, 144 P. vivax dhfr mutations were found at only 12 positions, of which 4 have not been described previously. An F3L mutation at residue 57 had been observed previously, but a novel codon (TTA) resulted in a mutation in seven of the nine mutated variant sequences. A new mutation at residue 117 resulted in S3T (S3N has been described previously). These two variants are the same as those observed in the P. falciparum dhfr gene at residue 108, where they are associated with different levels of antifolate resistance. Two novel mutations, I3L at residue 13 and T3M at residue 61, appear to be unique to P. vivax. The clinical, epidemiological, and sequence data suggest a sequential pathway for the acquisition of the P. vivax dhfr mutations. Mutations at residues 117 and 58 arise first when drug pressure is applied. Highly mutated genes carry the S3T rather than the S3N mutation at residue 117. Mutations at residues 57 and 61 then occur, followed by a fifth mutation at residue 13.With the global spread of chloroquine resistance in Plasmodium falciparum, the combination of sulfadoxine and pyrimethamine (S-P) is now used as first-line antimalarial treatment in an increasing number of countries. This is usually followed rapidly by the emergence of resistance. For example, in Thailand, high-level resistance to S-P arose within 5 years of its deployment in the late 1970s (14, 21). Similar patterns have been observed in other Asian countries, South America, and southern Africa. The combination of antifolate and sulfonamide drugs targets the folate metabolism of the malaria parasite. Molecular clinical and epidemiological studies have clearly shown that resistance to pyrimethamine and sulfadoxine results from specific point mutations in the parasite genes dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps), respectively. These cause alterations in crucial residues in the active sites of these enzymes, resulting in reduced drug affinity (5,11,13,(17)(18)(19)(20). Detection of these mutations in isolates in blood samples collected in the field has proved very valuable in the mapping of resistance and the monitoring of malaria control measures.In areas of malaria endemicity outside Africa, the prevalence of P. vivax equals and often exceeds that of P. falciparum. Chloroquine remains the first-line treatment for P. vivax infection, although in most areas wher...

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“…The diversity of P. vivax has been reported in terms of relapse patterns, morphology, and biochemistry (Figtree et al 2000). Ortholog genes of P. falciparum associated to drug resistance, such as PvDHFR related to pyrimethamine resistance (de Pecoulas et al 1998), PvCG10 to chloroquine resistance (Nomura et al 2001), and PvMDR1 to multiple drug resistance (Sá et al 2005) have been characterized for P. vivax. However, analysis does not confirm if these polymorphic genes are really related to resistant phenotypes.…”

Section: Polymorphic Molecular Markers and Genetic Diversitymentioning

confidence: 99%

The genetic diversity of Plasmodium vivax: a review

Souza-Neiras

Melo

Machado

2007

Mem. Inst. Oswaldo Cruz

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Analysis of the Plasmodium vivax dihydrofolate reductase–thymidylate synthase gene sequence

Cited by 64 publications

References 23 publications

Association of Genetic Mutations in Plasmodium vivax dhfr with Resistance to Sulfadoxine-Pyrimethamine: Geographical and Clinical Correlates

Association of Genetic Mutations in Plasmodium vivax dhfr with Resistance to Sulfadoxine-Pyrimethamine: Geographical and Clinical Correlates

Novel Point Mutations in the Dihydrofolate Reductase Gene of Plasmodium vivax : Evidence for Sequential Selection by Drug Pressure

The genetic diversity of Plasmodium vivax: a review

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