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Please use this identifier to cite or link to this item: http://repository.li.mahidol.ac.th/dspace/handle/123456789/40970
Title: Dihydrofolate-reductase mutations in plasmodium knowlesi appear unrelated to selective drug pressure from putative human-to-human transmission in Sabah, Malaysia
Authors: Matthew J. Grigg
Bridget E. Barber
Jutta Marfurt
Mallika Imwong
Timothy William
Elspeth Bird
Kim A. Piera
Ammar Aziz
Usa Boonyuen
Christopher J. Drakeley
Jonathan Cox
Nicholas J. White
Qin Cheng
Tsin W. Yeo
Sarah Auburn
Nicholas M. Anstey
Menzies School of Health Research
Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit
Mahidol University
Queen Elizabeth Hospital
Jesselton Medical Centre
London School of Hygiene & Tropical Medicine
Royal Darwin Hospital
Nanyang Technological University
Australian Army Malaria Institute
QIMR Berghofer Medical Research Institute
Keywords: Agricultural and Biological Sciences;Biochemistry, Genetics and Molecular Biology
Issue Date: 1-Mar-2016
Citation: PLoS ONE. Vol.11, No.3 (2016)
Abstract: © 2016 Grigg et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background Malaria caused by zoonotic Plasmodium knowlesi is an emerging threat in Eastern Malaysia. Despite demonstrated vector competency, it is unknown whether human-to-human (HH) transmission is occurring naturally. We sought evidence of drug selection pressure from the antimalarial sulfadoxine-pyrimethamine (SP) as a potential marker of H-H transmission. Methods The P. knowlesi dihdyrofolate-reductase (pkdhfr) gene was sequenced from 449 P. knowlesi malaria cases from Sabah (Malaysian Borneo) and genotypes evaluated for association with clinical and epidemiological factors. Homology modelling using the pvdhfr template was used to assess the effect of pkdhfr mutations on the pyrimethamine binding pocket. Results Fourteen non-synonymous mutations were detected, with the most common being at codon T91P (10.2%) and R34L (10.0%), resulting in 21 different genotypes, including the wild- type, 14 single mutants, and six double mutants. One third of the P. knowlesi infections were with pkdhfr mutants; 145 (32%) patients had single mutants and 14 (3%) had doublemutants. In contrast, among the 47 P. falciparum isolates sequenced, three pfdhfr genotypes were found, with the double mutant 108N+59R being fixed and the triple mutants 108N+59R+51I and 108N+59R+164L occurring with frequencies of 4% and 8%, respectively. Two non-random spatio-temporal clusters were identified with pkdhfr genotypes. There was no association between pkdhfr mutations and hyperparasitaemia or malaria severity, both hypothesized to be indicators of H-H transmission. The orthologous loci associated with resistance in P. falciparum were not mutated in pkdhfr. Subsequent homology modelling of pkdhfr revealed gene loci 13, 53, 120, and 173 as being critical for pyrimethamine binding, however, there were no mutations at these sites among the 449 P. knowlesi isolates. Conclusion Although moderate diversity was observed in pkdhfr in Sabah, there was no evidence this reflected selective antifolate drug pressure in humans.
URI: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84962243417&origin=inward
http://repository.li.mahidol.ac.th/dspace/handle/123456789/40970
ISSN: 19326203
Appears in Collections:Scopus 2016-2017

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