Analysis of the dihydrofolate reductase-thymidylate synthase gene sequences in Plasmodium vivax field isolates that failed chloroquine treatment

Malaria Journal

Research

Jetsumon Sattabongkot¹  Youngjoo Sohn²  Hyeong-Woo Lee³  Han-Sook Park⁴  Yien-Kyoung Choi⁴  Jung-Yeon Kim⁴  Mi-A Kim⁴  Won-Ja Lee⁴  Kyung-Mi Choi⁴  Hyuck Kim⁵  Jong-Koo Lee⁶  Hyung-Hwan Kim⁷ 

[1] Department of Entomology, Armed Forces Research Institute of Medical Sciences, 10400, Bangkok, Thailand;Department of Gynecology, College of Oriental Medicine, Sangji University, 220-717, Wonju, Republic of Korea;Department of Pathology, University of Florida, J-566, 1600 SW Archer Road, 32610, Gainesville, FL, USA;Division of Malaria and Parasitic diseases, National Institute of Health, Korea Centers for Disease Control and Prevention, 122-701, Seoul, Republic of Korea;International Research Center for Bioscience and Biotechnology, 367-805, Goesan, Republic of Korea;Korea Centers for Disease Control and Prevention, Ministry of Health & Welfare, 122-701, Seoul, Republic of Korea;Vascular Medicine Research Unit, Brigham and Women's Hospital, Harvard Medical School, 02139, Cambridge, MA, USA;International Research Center for Bioscience and Biotechnology, 367-805, Goesan, Republic of Korea;

关键词: Malaria;    Artesunate;    Vivax Malaria;    Pyrimethamine;    Primaquine;   

DOI  :  10.1186/1475-2875-9-331

 received in 2010-06-16, accepted in 2010-11-18,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundTo use pyrimethamine as an alternative anti-malarial drug for chloroquine-resistant malaria parasites, it was necessary to determine the enzyme's genetic variation in dihydrofolate reductase-thymidylate syntase (DHFR-TS) among Korean strains.MethodsGenetic variation of dhfr-ts genes of Plasmodium vivax clinical isolates from patients who did not respond to drug treatment (n = 11) in Korea were analysed. The genes were amplified using the polymerase chain reaction (PCR) with genomic DNA as a template.ResultsSequence analysis showed that the open reading frame (ORF) of 1,857 nucleotides encoded a deduced protein of 618 amino acids (aa). Alignment with the DHFR-TS genes of other malaria parasites showed that a 231-residue DHFR domain and a 286-residue TS domain were seperated by a 101-aa linker region. This ORF shows 98.7% homology with the P. vivax Sal I strain (XM001615032) in the DHFR domain, 100% in the linker region and 99% in the TS domain. Comparison of the DHFR sequences from pyrimethamine-sensitive and pyrimethamine-resistant P. vivax isolates revealed that nine isolates belonged to the sensitive strain, whereas two isolates met the criteria for resistance. In these two isolates, the amino acid at position 117 is changed from serine to asparagine (S117N). Additionally, all Korean isolates showed a deletion mutant of THGGDN in short tandem repetitive sequences between 88 and 106 amino acid.ConclusionsThese results suggest that sequence variations in the DHFR-TS represent the prevalence of antifolate-resistant P. vivax in Korea. Two of 11 isolates have the Ser to Asn mutation in codon 117, which is the major determinant of pyrimethamine resistance in P. vivax. Therefore, the introduction of pyrimethamine for the treatment of chloroquine-resistant vivax malaria as alternative drug in Korea should be seriously considered.

【 授权许可】

CC BY   
© Lee et al; licensee BioMed Central Ltd. 2010