AAC
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Imwong, M.
Right arrow Articles by Snounou, G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Imwong, M.
Right arrow Articles by Snounou, G.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, May 2003, p. 1514-1521, Vol. 47, No. 5
0066-4804/03/$08.00+0     DOI: 10.1128/AAC.47.5.1514-1521.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

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

Mallika Imwong,1 Sasithon Pukrittayakamee,1 Laurent Rénia,2 Franck Letourneur,3 Jean-Paul Charlieu,4,{dagger} Ubolsree Leartsakulpanich,5 Sornchai Looareesuwan,1 Nicholas J. White,1,6* and Georges Snounou7

Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University,1 National Centre for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok, Thailand,5 Département d'Immunologie, INSERM U567, CNRS UHR8104, Institut Cochin,2 Laboratoire Commun de Séquençage, Institut Cochin, Université René Descartes, Paris 75014,3 Unité de Parasitologie Bio-Médicale, CNRS URA1960, Institut Pasteur, Paris, France,7 Wellcome Trust Clinical Research Unit, Ho Chi Minh City, Vietnam,4 Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford, United Kingdom6

Received 16 September 2002/ Returned for modification 27 November 2002/ Accepted 30 January 2003

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 F->L 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 S->T (S->N 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, I->L at residue 13 and T->M 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 S->T rather than the S->N mutation at residue 117. Mutations at residues 57 and 61 then occur, followed by a fifth mutation at residue 13.

* Corresponding author. Mailing address: Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd., Bangkok 10400, Thailand. Phone: 66-2-246-0832. Fax. 66-2-246-7795. E-mail: fnnjw{at}diamond.mahidol.ac.th.

{dagger} Deceased.

Antimicrobial Agents and Chemotherapy, May 2003, p. 1514-1521, Vol. 47, No. 5
0066-4804/03/$08.00+0     DOI: 10.1128/AAC.47.5.1514-1521.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Clin. Vaccine Immunol. Clin. Microbiol. Rev.
J. Clin. Microbiol. ALL ASM JOURNALS

Copyright © 2003 by the American Society for Microbiology. All rights reserved.