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Analysis of Plasmodium falciparum Na +/H + exchanger (pfnhe1) polymorphisms among imported African malaria parasites isolated in Wuhan, Central China. BMC Infect Dis 2019; 19:354. [PMID: 31035938 PMCID: PMC6489200 DOI: 10.1186/s12879-019-3921-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/19/2019] [Indexed: 11/30/2022] Open
Abstract
Background Quinine (QN) remains an effective drug for malaria treatment. However, quinine resistance (QNR) in Plasmodium falciparum has been reported in many malaria-endemic regions particularly in African countries. Genetic polymorphism of the P. falciparum Na+/H+ exchanger (pfnhe1) is considered to influence QN susceptibility. Here, ms4760 alleles of pfnhe1 were analysed from imported African P. falciparum parasites isolated from returning travellers in Wuhan, Central China. Methods A total of 204 dried-blood spots were collected during 2011–2016. The polymorphisms of the pfnhe1 gene were determined using nested PCR with DNA sequencing. Results Sequences were generated for 99.51% (203/204) of the PCR products and 68.63% (140/204) of the isolates were analysed successfully for the pfnhe1 ms4760 haplotypes. In total, 28 distinct ms4760 alleles containing 0 to 5 DNNND and 1 to 3 NHNDNHNNDDD repeats were identified. For the alleles, ms4760–1 (22.86%, 32/140), ms4760–3 (17.86%, 25/140), and ms4760–7 (10.71%, 15/140) were the most prevalent profiles. Furthermore, 5 undescribed ms4760 alleles were reported. Conclusions The study offers an initial comprehensive analysis of pfnhe1 ms4760 polymorphisms from imported P. falciparum isolates in Wuhan. Pfnhe1 may constitute a good genetic marker to evaluate the prevalence of QNR in malaria-endemic and non-endemic regions.
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Carrington E, Otto TD, Szestak T, Lennartz F, Higgins MK, Newbold CI, Craig AG. In silico guided reconstruction and analysis of ICAM-1-binding var genes from Plasmodium falciparum. Sci Rep 2018; 8:3282. [PMID: 29459671 PMCID: PMC5818487 DOI: 10.1038/s41598-018-21591-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 02/07/2018] [Indexed: 11/23/2022] Open
Abstract
The Plasmodium falciparum variant surface antigen PfEMP1 expressed on the surface of infected erythrocytes is thought to play a major role in the pathology of severe malaria. As the sequence pool of the var genes encoding PfEMP1 expands there are opportunities, despite the high degree of sequence diversity demonstrated by this gene family, to reconstruct full-length var genes from small sequence tags generated from patient isolates. To test whether this is possible we have used a set of recently laboratory adapted ICAM-1-binding parasite isolates to generate sequence tags and, from these, to identify the full-length PfEMP1 being expressed by them. In a subset of the strains available we were able to produce validated, full-length var gene sequences and use these to conduct biophysical analyses of the ICAM-1 binding regions.
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Affiliation(s)
- Eilidh Carrington
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- Malaria Gene Regulation Lab, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland
| | - Thomas D Otto
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
- Institute of Infection, Immunity and Inflammation, University of Glasgow, College of Medical, Veterinary and Life Sciences, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Tadge Szestak
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Frank Lennartz
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Matt K Higgins
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Chris I Newbold
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DS, UK
| | - Alister G Craig
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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Costa GL, Amaral LC, Fontes CJF, Carvalho LH, de Brito CFA, de Sousa TN. Assessment of copy number variation in genes related to drug resistance in Plasmodium vivax and Plasmodium falciparum isolates from the Brazilian Amazon and a systematic review of the literature. Malar J 2017; 16:152. [PMID: 28420389 PMCID: PMC5395969 DOI: 10.1186/s12936-017-1806-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 04/07/2017] [Indexed: 12/29/2022] Open
Abstract
Background Parasite resistance to anti-malarials represents a great obstacle for malaria elimination. The majority of studies have investigated the association between single-nucleotide polymorphisms (SNPs) and drug resistance; however, it is becoming clear that the copy number variation (CNV) is also associated with this parasite phenotype. To provide a baseline for molecular surveillance of anti-malarial drug resistance in the Brazilian Amazon, the present study characterized the genetic profile of both markers in the most common genes associated with drug resistance in Plasmodium falciparum and Plasmodium vivax isolates. Additionally, these data were compared to data published elsewhere applying a systematic review of the literature published over a 20-year time period. Methods The genomic DNA of 67 patients infected by P. falciparum and P. vivax from three Brazilian States was obtained between 2002 and 2012. CNV in P. falciparum multidrug resistance gene-1 (pfmdr1), GTP cyclohydrolase 1 (pfgch1) and P. vivax multidrug resistance gene-1 (pvmdr1) were assessed by real-time PCR assays. SNPs in the pfmdr1 and pfcrt genes were assessed by PCR–RFLP. A literature search for studies that analysed CNP in the same genes of P. falciparum and P. vivax was conducted between May 2014 and March 2017 across four databases. Results All analysed samples of P. falciparum carried only one copy of pfmdr1 or pfgch1. Although the pfcrt K76T polymorphism, a determinant of CQ resistance, was present in all samples genotyped, the pfmdr1 N86Y was absent. For P. vivax isolates, an amplification rate of 20% was found for the pvmdr1 gene. The results of the study are in agreement with the low amplification rates for pfmdr1 gene evidenced in the Americas and Africa, while higher rates have been described in Southeast Asia. For P. vivax, very low rates of amplification for pvmdr1 have been described worldwide, with exceptions in French Guiana, Cambodia, Thailand and Brazil. Conclusions The present study was the first to evaluate gch1 CNV in P. falciparum isolates from Brazil, showing an absence of amplification of this gene more than 20 years after the withdrawal of the Brazilian antifolates therapeutic scheme. Furthermore, the rate of pvmdr1 amplification was significantly higher than that previously reported for isolates circulating in Northern Brazil. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1806-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gabriel Luíz Costa
- Molecular Biology and Malaria Immunology Research Group, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | - Lara Cotta Amaral
- Molecular Biology and Malaria Immunology Research Group, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | | | - Luzia Helena Carvalho
- Molecular Biology and Malaria Immunology Research Group, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | - Cristiana Ferreira Alves de Brito
- Molecular Biology and Malaria Immunology Research Group, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | - Taís Nóbrega de Sousa
- Molecular Biology and Malaria Immunology Research Group, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil.
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Mungthin M, Watanatanasup E, Sitthichot N, Suwandittakul N, Khositnithikul R, Ward SA. Influence of the pfmdr1 Gene on In Vitro Sensitivities of Piperaquine in Thai Isolates of Plasmodium falciparum. Am J Trop Med Hyg 2017; 96:624-629. [PMID: 28044042 DOI: 10.4269/ajtmh.16-0668] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Piperaquine combined with dihydroartemisinin is one of the artemisinin derivative combination therapies, which can replace artesunate-mefloquine in treating uncomplicated falciparum malaria in Thailand. The aim of this study was to determine the in vitro sensitivity of Thai Plasmodium falciparum isolates against piperaquine and the influence of the pfmdr1 gene on in vitro response. One hundred and thirty-seven standard laboratory and adapted Thai isolates of P. falciparum were assessed for in vitro piperaquine sensitivity. Polymorphisms of the pfmdr1 gene were determined by polymerase chain reaction methods. The mean and standard deviation of the piperaquine IC50 in Thai isolates of P. falciparum were 16.7 ± 6.3 nM. The parasites exhibiting chloroquine IC50 of ≥ 100 nM were significantly less sensitive to piperaquine compared with the parasite with chloroquine IC50 of < 100 nM. No significant association between the pfmdr1 copy number and piperaquine IC50 values was found. In contrast, the parasites containing the pfmdr1 86Y allele exhibited significantly reduced piperaquine sensitivity. Before nationwide implementation of dihydroartemisinin-piperaquine as the first-line treatment in Thailand, in vitro and in vivo evaluations of this combination should be performed especially in areas where parasites containing the pfmdr1 86Y allele are predominant such as the Thai-Malaysian border.
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Affiliation(s)
- Mathirut Mungthin
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, Thailand
| | | | - Naruemon Sitthichot
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, Thailand
| | | | | | - Stephen A Ward
- Division of Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Alareqi LM, Mahdy MA, Lau YL, Fong MY, Abdul-Ghani R, Mahmud R. Molecular markers associated with resistance to commonly used antimalarial drugs among Plasmodium falciparum isolates from a malaria-endemic area in Taiz governorate-Yemen during the transmission season. Acta Trop 2016; 162:174-179. [PMID: 27343362 DOI: 10.1016/j.actatropica.2016.06.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/13/2016] [Accepted: 06/13/2016] [Indexed: 12/28/2022]
Abstract
Since 2005, artesunate (AS) plus sulfadoxine/pyrimethamine (SP) combination has been adopted as the first-line treatment for uncomplicated malaria in Yemen in response to the high level of Plasmodium falciparum resistance to chloroquine (CQ). Therefore, the aim of the present study was to determine the frequency distribution of molecular markers associated with resistance to CQ and AS plus SP combination among P. falciparum isolates from a malaria-endemic area in Taiz governorate, Yemen. Fifty P. falciparum isolates were collected during a cross-sectional study in Mawza district, Taiz, in the period from October 2013 to April 2014. The isolates were investigated for drug resistance-associated molecular markers in five genes, including P. falciparum CQ resistance transporter (pfcrt) 76T and P. falciparum multidrug resistance 1 (pfmdr1) 86Y as markers of resistance to CQ, mutations in the Kelch 13 (K13) propeller domain for resistance to AS, and P. falciparum dihydrofolate reductase (pfdhfr) and P. falciparum dihydropteroate synthase (pfdhps) genes for resistance to SP. Nested polymerase chain reaction was used to amplify target genes in DNA extracts of the isolates followed by restriction fragment length polymorphism for detecting 76T and 86Y mutations in pfcrt and pfmdr1, respectively, and by DNA sequencing for detecting mutations in K13, pfdhfr and pfdhps. All the investigated isolates from Mawza district were harboring the pfcrt 76T mutant and the pfmdr1 N86 wild-type alleles. The pfdhfr 51I/108N double mutant allele was found in 2.2% (1/45) of the isolates; however, no mutations were detected at codons 436, 437, 540, 581 and 613 of pfdhps. All P. falciparum isolates that were successfully sequenced (n=47) showed the K13 Y493, R539, I543 and C580 wild-type alleles. In conclusion, the pfcrt 76T mutant allele is fixed in the study area about six years after the official withdrawal of CQ, possibly indicating its over-the-counter availability and continued use as a self-medication in the study area. However, the almost predominant wild-type alleles of the genes associated with resistance to AS and SP among P. falciparum isolates in the present study indicates the sustained efficacy of the currently adopted first-line treatment of AS plus SP in the study area.
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Phompradit P, Muhamad P, Chaijaroenkul W, Na-Bangchang K. Genetic polymorphisms of candidate markers and in vitro susceptibility of Plasmodium falciparum isolates from Thai-Myanmar border in relation to clinical response to artesunate-mefloquine combination. Acta Trop 2014; 139:77-83. [PMID: 25004442 DOI: 10.1016/j.actatropica.2014.06.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 06/25/2014] [Accepted: 06/29/2014] [Indexed: 11/15/2022]
Abstract
The genetic polymorphisms of the candidate markers of antimalarial drug resistance pfcrt, pfmdr1, pfatp6, and pfmrp1 were investigated in relationship with in vitro susceptibility of Plasmodium falciparum isolates and clinical response following artesunate (AS)-mefloquine (MQ) combination in 21 and 27 samples obtained from patients with recrudescence and adequate clinical response, respectively. MQ (21.0 vs. 49.9nM) and AS (1.6 vs. 2.8nM) IC50 values (concentrations that inhibit parasite growth by 50%) were significantly higher in isolates collected from patients with recrudescence. Furthermore, a significantly higher MQ IC50 was found in isolates from patients with recrudescence that carried pfmrp1 mutations at amino acid residues 191Y, 437A, and 876V. For AS sensitivity, a significant association was also detected in isolates from patients with recrudescence that carried gene mutations at amino acid residues 437A and 876V. MQ IC50 of the isolates with recrudescence which carried ≥4 pfmdr1 gene copies was significantly higher than that carrying only one gene copy. In addition, a significantly higher proportion of isolates carrying one gene copy was detected in the group with adequate clinical response compared with recrudescence. Results from this limited sample size suggested the potential link between pfmdr1 gene copy number and pfmrp1 gene mutation, in vitro parasite susceptibility, and AS-MQ treatment response.
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Affiliation(s)
- Papichaya Phompradit
- Graduate program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University (Rangsit Campus), Patumthani 12121, Thailand
| | - Poonuch Muhamad
- Thailand center of Excellence on Drug Discovery and Development, Thammasat University (Rangsit campus), Patumthani 12121, Thailand
| | - Wanna Chaijaroenkul
- Chulabhorn International College of Medicine, Thammasat University (Rangsit Campus), Patumthani 12121, Thailand
| | - Kesara Na-Bangchang
- Chulabhorn International College of Medicine, Thammasat University (Rangsit Campus), Patumthani 12121, Thailand.
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Madkhali AM, Alkurbi MO, Szestak T, Bengtsson A, Patil PR, Wu Y, Alharthi S, Jensen ATR, Pleass R, Craig AG. An analysis of the binding characteristics of a panel of recently selected ICAM-1 binding Plasmodium falciparum patient isolates. PLoS One 2014; 9:e111518. [PMID: 25360558 PMCID: PMC4216080 DOI: 10.1371/journal.pone.0111518] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 09/30/2014] [Indexed: 12/21/2022] Open
Abstract
The basis of severe malaria pathogenesis in part includes sequestration of Plasmodium falciparum-infected erythrocytes (IE) from the peripheral circulation. This phenomenon is mediated by the interaction between several endothelial receptors and one of the main parasite-derived variant antigens (PfEMP1) expressed on the surface of the infected erythrocyte membrane. One of the commonly used host receptors is ICAM-1, and it has been suggested that ICAM-1 has a role in cerebral malaria pathology, although the evidence to support this is not conclusive. The current study examined the cytoadherence patterns of lab-adapted patient isolates after selecting on ICAM-1. We investigated the binding phenotypes using variant ICAM-1 proteins including ICAM-1Ref, ICAM-1Kilifi, ICAM-1S22/A, ICAM-1L42/A and ICAM-1L44/A using static assays. The study also examined ICAM-1 blocking by four anti-ICAM-1 monoclonal antibodies (mAb) under static conditions. We also characterised the binding phenotypes using Human Dermal Microvascular Endothelial Cells (HDMEC) under flow conditions. The results show that different isolates have variant-specific binding phenotypes under both static and flow conditions, extending our previous observations that this variation might be due to variable contact residues on ICAM-1 being used by different parasite PfEMP1 variants.
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Affiliation(s)
- Aymen M. Madkhali
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Medical Laboratories Technology, College of Applied Medical Sciences, Jazan University, Jazan, Kingdom of Saudi Arabia
| | - Mohammed O. Alkurbi
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Laboratory Medicine, College of Applied Medical Sciences, Umm Al-Qura University, Makkah Al-Mukarramah, Kingdom of Saudi Arabia
| | - Tadge Szestak
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Anja Bengtsson
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Pradeep R. Patil
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Yang Wu
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Saeed Alharthi
- Department of Laboratory Medicine, College of Applied Medical Sciences, Umm Al-Qura University, Makkah Al-Mukarramah, Kingdom of Saudi Arabia
| | - Anja T. R. Jensen
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Richard Pleass
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Alister G. Craig
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * E-mail:
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Role of Pfmdr1 in in vitro Plasmodium falciparum susceptibility to chloroquine, quinine, monodesethylamodiaquine, mefloquine, lumefantrine, and dihydroartemisinin. Antimicrob Agents Chemother 2014; 58:7032-40. [PMID: 25199781 DOI: 10.1128/aac.03494-14] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The involvement of Pfmdr1 (Plasmodium falciparum multidrug resistance 1) polymorphisms in antimalarial drug resistance is still debated. Here, we evaluate the association between polymorphisms in Pfmdr1 (N86Y, Y184F, S1034C, N1042D, and D1246Y) and Pfcrt (K76T) and in vitro responses to chloroquine (CQ), mefloquine (MQ), lumefantrine (LMF), quinine (QN), monodesethylamodiaquine (MDAQ), and dihydroartemisinin (DHA) in 174 Plasmodium falciparum isolates from Dakar, Senegal. The Pfmdr1 86Y mutation was identified in 14.9% of the samples, and the 184F mutation was identified in 71.8% of the isolates. No 1034C, 1042N, or 1246Y mutations were detected. The Pfmdr1 86Y mutation was significantly associated with increased susceptibility to MDAQ (P = 0.0023), LMF (P = 0.0001), DHA (P = 0.0387), and MQ (P = 0.00002). The N86Y mutation was not associated with CQ (P = 0.214) or QN (P = 0.287) responses. The Pfmdr1 184F mutation was not associated with various susceptibility responses to the 6 antimalarial drugs (P = 0.168 for CQ, 0.778 for MDAQ, 0.324 for LMF, 0.961 for DHA, 0.084 for QN, and 0.298 for MQ). The Pfmdr1 86Y-Y184 haplotype was significantly associated with increased susceptibility to MDAQ (P = 0.0136), LMF (P = 0.0019), and MQ (P = 0.0001). The additional Pfmdr1 86Y mutation increased significantly the in vitro susceptibility to MDAQ (P < 0.0001), LMF (P < 0.0001), MQ (P < 0.0001), and QN (P = 0.0026) in wild-type Pfcrt K76 parasites. The additional Pfmdr1 86Y mutation significantly increased the in vitro susceptibility to CQ (P = 0.0179) in Pfcrt 76T CQ-resistant parasites.
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Pathak A, Mårtensson A, Gawariker S, Mandliya J, Sharma A, Diwan V, Ursing J. Characterization of drug resistance associated genetic polymorphisms among Plasmodium falciparum field isolates in Ujjain, Madhya Pradesh, India. Malar J 2014; 13:182. [PMID: 24885535 PMCID: PMC4036110 DOI: 10.1186/1475-2875-13-182] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 05/07/2014] [Indexed: 12/28/2022] Open
Abstract
Background Since 2011, artesunate + sulphadoxine-pyrimethamine (ASP), instead of chloroquine, has been recommended for treatment of uncomplicated malaria in India. In Ujjain, central India, with an annual parasite index <0.1, the prevalence of drug-resistant Plasmodium falciparum is unknown. In other parts of India chloroquine and sulphadoxine-pyrimethamine-resistant P. falciparum is prevalent. The aim of this study was to determine the prevalence of anti-malarial drug resistance-associated genetic polymorphisms in P. falciparum collected in Ujjain in 2009 and 2010, prior to the introduction of ASP. Methods Blood samples from 87 patients with P. falciparum mono-infection verified by microscopy were collected on filter-paper at all nine major pathology laboratories in Ujjain city. Codons Pfcrt 72–76, pfmdr1 1034–1246, pfdhfr 16–185, pfdhps 436–632 and pfnhe1 ms4760 haplotypes were identified by sequencing. Pfcrt K76T and pfmdr1 N86Y were identified by restriction fragment length polymorphism, and pfmdr1 gene copy number by real-time PCR. Results Sulphadoxine-pyrimethamine resistance-associated pfdhfr 108 N and 59R alleles were found in 75/78 (96%) and 70/78 (90%) samples, respectively, and pfdhps 437G was found in 7/77 (9%) samples. Double mutant pfdhfr 59R + 108 N were found in 62/76 (82%) samples. Triple mutant pfdhfr 59R + 108 N and pfdhps 437G were found in 6/76 (8%) samples. Chloroquine-resistance-associated pfcrt 76 T was found in 82/87 (94%). The pfcrt 72–76 haplotypes found were: 80/84 (95%) SVMNT, 3/84 (4%) CVMNK and 1/84 (1%) CVMNT. Pfmdr1 N86 and 86Y were identified in 70/83 (84%) and 13/83 (16%) samples, respectively. Pfmdr1 S1034 + N1042 + D1246 were identified together in 70/72 (97%) of successfully sequenced samples. One pfmdr1 gene copy was found in 74/75 (99%) successfully amplified samples. Conclusion This is the first characterization of key anti-malarial drug resistance-associated genetic markers among P. falciparum collected in Ujjain, Madhya Pradesh, India. The results indicate that the efficacy of standard dose chloroquine at the time of the study was likely to be poor, whereas ASP was likely to be efficacious, supporting the changed drug treatment policy. However, P. falciparum with reduced susceptibility to sulphadoxine-pyrimethamine is highly prevalent, highlighting the need for continuous surveillance of ASP efficacy in the study area.
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Affiliation(s)
| | | | | | | | | | | | - Johan Ursing
- Malaria Research, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.
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Sanchez CP, Liu CH, Mayer S, Nurhasanah A, Cyrklaff M, Mu J, Ferdig MT, Stein WD, Lanzer M. A HECT ubiquitin-protein ligase as a novel candidate gene for altered quinine and quinidine responses in Plasmodium falciparum. PLoS Genet 2014; 10:e1004382. [PMID: 24830312 PMCID: PMC4022464 DOI: 10.1371/journal.pgen.1004382] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 04/01/2014] [Indexed: 11/18/2022] Open
Abstract
The emerging resistance to quinine jeopardizes the efficacy of a drug that has been used in the treatment of malaria for several centuries. To identify factors contributing to differential quinine responses in the human malaria parasite Plasmodium falciparum, we have conducted comparative quantitative trait locus analyses on the susceptibility to quinine and also its stereoisomer quinidine, and on the initial and steady-state intracellular drug accumulation levels in the F1 progeny of a genetic cross. These data, together with genetic screens of field isolates and laboratory strains associated differential quinine and quinidine responses with mutated pfcrt, a segment on chromosome 13, and a novel candidate gene, termed MAL7P1.19 (encoding a HECT ubiquitin ligase). Despite a strong likelihood of association, episomal transfections demonstrated a role for the HECT ubiquitin-protein ligase in quinine and quinidine sensitivity in only a subset of genetic backgrounds, and here the changes in IC50 values were moderate (approximately 2-fold). These data show that quinine responsiveness is a complex genetic trait with multiple alleles playing a role and that more experiments are needed to unravel the role of the contributing factors. Quinine, a natural product from cinchona bark, has been used in the treatment of malaria for centuries. Unfortunately, a progressive loss in responsiveness of the human malaria parasite Plasmodium falciparum to quinine has been observed, particularly in Southeast Asia, where cases of quinine treatment failure regularly occur. To better understand how P. falciparum defends itself against the cytotoxic activity of quinine, we have conducted comparative linkage analyses in the F1 progeny of a genetic cross where we assessed the susceptibility and the amount of intracellular accumulation of quinine and of its stereoisomer quinidine. These data identified a novel candidate gene encoding a HECT ubiquitin-protein ligase that might contribute to altered quinine responsiveness. The identification of this novel gene might improve the surveillance of quinine-resistant malaria parasites in the field and aid the preservation of this valuable antimalarial drug.
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Affiliation(s)
- Cecilia P. Sanchez
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Chia-Hao Liu
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Sybille Mayer
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Astutiati Nurhasanah
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
- Laboratory for the Development of Agroindustrial and Biomedical Technology (LAPTIAB), Tangerang Selatan, Indonesia
| | - Marek Cyrklaff
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Jianbing Mu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, United States of America
| | - Michael T. Ferdig
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Wilfred D. Stein
- Biological Chemistry, Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Michael Lanzer
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
- * E-mail:
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Mungthin M, Intanakom S, Suwandittakul N, Suida P, Amsakul S, Sitthichot N, Thammapalo S, Leelayoova S. Distribution of pfmdr1 polymorphisms in Plasmodium falciparum isolated from Southern Thailand. Malar J 2014; 13:117. [PMID: 24670242 PMCID: PMC3986879 DOI: 10.1186/1475-2875-13-117] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Accepted: 03/22/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Drug resistance in Plasmodium falciparum is a major problem in malaria control especially along the Thai-Myanmar and Thai-Cambodia borders. To date, a few molecular markers have been identified for anti-malarial resistance in P. falciparum, including the P. falciparum chloroquine resistance transporter (pfcrt) and the P. falciparum multidrug resistance 1 (pfmdr1). However no information is available regarding the distribution pattern of these gene polymorphisms in the parasites from the Thai-Malaysia border. This study was conducted to compare the distribution pattern of the pfcrt and pfmdr1 polymorphisms in the parasites from the lower southern provinces, Thai-Malaysia border and the upper southern provinces, Thai-Myanmar border. In addition, in vitro sensitivities of anti-malarial drugs including chloroquine, mefloquine, quinine, and artesunate were determined. METHODS In all, 492 P. falciparum-positive blood samples were collected from the lower southern provinces: Songkhla, Yala and Narathiwas. From the upper southern part of Thailand, Ranong and Chumphon, 66 samples were also collected. Polymorphisms of the pfcrt and the pfmdr1 gene were determined using PCR techniques. In vitro sensitivities of anti-malarial drugs were determined using radioisotopic method. RESULTS All parasites from both areas contained the pfcrt 76 T allele. The pfmdr1 86Y allele was significantly more common in the parasites isolated from the lower southern areas. In contrast, the pfmdr1 184F allele was predominant among the parasites from the upper southern areas especially Ranong. In addition, the parasites from Ranong contained higher copy numbers than the parasites from other provinces. All adapted parasite isolates exhibited CQ-resistant phenotype. Neither QN nor MQ resistance was detected in these isolates. CONCLUSION The parasites from Thai-Malaysia border exhibited different resistant patterns compared to other areas along the international border of Thailand. This information will be useful for anti-malarial drug policy in Thailand.
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Affiliation(s)
- Mathirut Mungthin
- Department of Parasitology, Phramongkutklao College of Medicine, Ratchawithi Rd, Bangkok 10400, Thailand.
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Pascual A, Fall B, Wurtz N, Fall M, Camara C, Nakoulima A, Baret E, Diatta B, Fall KB, Mbaye PS, Diémé Y, Bercion R, Bogreau H, Briolant S, Rogier C, Wade B, Pradines B. In vitro susceptibility to quinine and microsatellite variations of the Plasmodium falciparum Na+/H+ exchanger transporter (Pfnhe-1) gene in 393 isolates from Dakar, Senegal. Malar J 2013; 12:189. [PMID: 23758769 PMCID: PMC3679854 DOI: 10.1186/1475-2875-12-189] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Accepted: 06/03/2013] [Indexed: 11/10/2022] Open
Abstract
Background Although the World Health Organization recommends replacing quinine (QN) by artesunate due to its increased efficacy and the higher tolerance to the drug in both adults and children, QN remains a first-line treatment for severe malaria, especially in Africa. Investigations of microsatellite Pfnhe-1 ms4760 polymorphisms in culture-adapted isolates from around the world have revealed that an increase in the number of DNNND amino acid motifs was associated with decreased QN susceptibility, whereas an increase in the number of DDNHNDNHNND motifs was associated with increased QN susceptibility. Methods In this context, to further analyse associations between Pfnhe-1 ms4760 polymorphisms and QN susceptibility, 393 isolates freshly collected between October 2009 and January 2010 and July 2010 and February 2011, respectively, at the Hôpital Principal de Dakar, Senegal were assessed ex vivo for QN susceptibility, and their genes were amplified and sequenced. Results Of the 393 Plasmodium falciparum clinical isolates collected, 145 were successfully cultured. The 145 QN IC50s ranged from 2.1 to 1291 nM, and 17 isolates (11.7%) exceed the QN reduced susceptibility threshold of 611 nM. Among the 393 P. falciparum clinical isolates, 47 different alleles were observed. The three most prevalent profiles were ms4760-1 (no = 72; 18.3%), ms4760-3 (no = 65; 16.5%) and ms4760-7 (no = 40; 10.2%). There were no significant associations observed between QN IC50 values and i) the number of repeats of DNNND in block II (p = 0.0955, Kruskal-Wallis test); ii) the number of repeats of DDNHNDNHNND in block V (p = 0.1455, Kruskal-Wallis test); or iii) ms4760 profiles (p = 0.1809, Kruskal-Wallis test). Conclusions Pfnhe-1 ms4760 was highly diverse in parasite isolates from Dakar (47 different profiles). Three profiles (ms4760-1, ms4760-3 and ms4760-7) were predominant. The number of repeats for block II (DNNND) or block V (DDNHNDNHNND) was not significantly associated with QN susceptibility. New studies, and especially in vivo studies, are necessary to confirm the role of Pfnhe-1 ms4760 as a marker of QN resistance.
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Affiliation(s)
- Aurélie Pascual
- Département d'Infectiologie de Terrain, Unité de Parasitologie, Institut de Recherche Biomédicale des Armées, Marseille, France
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13
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Andriantsoanirina V, Khim N, Ratsimbasoa A, Witkowski B, Benedet C, Canier L, Bouchier C, Tichit M, Durand R, Ménard D. Plasmodium falciparum Na+/H+ exchanger (pfnhe-1) genetic polymorphism in Indian Ocean malaria-endemic areas. Am J Trop Med Hyg 2012. [PMID: 23208889 DOI: 10.4269/ajtmh.2012.12-0359] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
To date, 11 studies conducted in different countries to test the association between Plasmodium falciparum Na(+)/H(+) exchanger gene (pfnhe-1; PF13_0019) polymorphisms and in vitro susceptibility to quinine have generated conflicting data. In this context and to extend our knowledge of the genetic polymorphism of Pfnhe gene, we have sequenced the ms4760 locus from 595 isolates collected in the Comoros (N = 250; an area with a high prevalence of chloroquine and sulfadoxine-pyrimethamine resistance) and Madagascar (N = 345; a low drug-resistance area). Among them, 29 different alleles were observed, including 8 (27%) alleles not previously described. Isolates from the Comoros showed more repeats in block II (DNNND), which some studies have found to be positively associated with in vitro resistance to quinine, compared with isolates from Madagascar. Additional studies are required to better define the mechanisms underlying quinine resistance, which involve multiple gene interactions.
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14
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Kone A, Mu J, Maiga H, Beavogui AH, Yattara O, Sagara I, Tekete MM, Traore OB, Dara A, Dama S, Diallo N, Kodio A, Traoré A, Björkman A, Gil JP, Doumbo OK, Wellems TE, Djimde AA. Quinine treatment selects the pfnhe-1 ms4760-1 polymorphism in Malian patients with Falciparum malaria. J Infect Dis 2012; 207:520-7. [PMID: 23162138 DOI: 10.1093/infdis/jis691] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The mechanism of Plasmodium falciparum resistance to quinine is not known. In vitro quantitative trait loci mapping suggests involvement of a predicted P. falciparum sodium-hydrogen exchanger (pfnhe-1) on chromosome 13. METHODS We conducted prospective quinine efficacy studies in 2 villages, Kollé and Faladié, Mali. Cases of clinical malaria requiring intravenous therapy were treated with standard doses of quinine and followed for 28 days. Treatment outcomes were classified using modified World Health Organization protocols. Molecular markers of parasite polymorphisms were used to distinguish recrudescent parasites from new infections. The prevalence of pfnhe-1 ms4760-1 among parasites before versus after quinine treatment was determined by direct sequencing. RESULTS Overall, 163 patients were enrolled and successfully followed. Without molecular correction, the mean adequate clinical and parasitological response (ACPR) was 50.3% (n = 163). After polymerase chain reaction correction to account for new infections, the corrected ACPR was 100%. The prevalence of ms4760-1 increased significantly, from 26.2% (n = 107) before quinine treatment to 46.3% (n = 54) after therapy (P = .01). In a control sulfadoxine-pyrimethamine study, the prevalence of ms4760-1 was similar before and after treatment. CONCLUSIONS This study supports a role for pfnhe-1 in decreased susceptibility of P. falciparum to quinine in the field.
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Affiliation(s)
- Aminatou Kone
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy, and Odonto-Stomatology, University of Science, Techniques and Technology, Bamako, Mali
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15
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Ménard D, Andriantsoanirina V, Khim N, Ratsimbasoa A, Witkowski B, Benedet C, Canier L, Mercereau-Puijalon O, Durand R. Global analysis of Plasmodium falciparum Na(+)/H(+) exchanger (pfnhe-1) allele polymorphism and its usefulness as a marker of in vitro resistance to quinine. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2012; 3:8-19. [PMID: 24533289 DOI: 10.1016/j.ijpddr.2012.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 10/06/2012] [Accepted: 10/09/2012] [Indexed: 11/30/2022]
Abstract
The aim of this study was to provide a comprehensive analysis of the worldwide genetic polymorphism of ms4760 alleles of the pfnhe-1 gene and to discuss their usefulness as molecular marker of quinine resistance (QNR). A new numbering of ms4760 allele, classification grouping ms4760 alleles according to the number of DNNND and DDNHNDNHNND repeat motifs in blocks II and V was also proposed. A total of 1508 ms4760 sequences from isolates, culture-adapted parasites or reference strains from various geographical regions were retrieved from GenBank (last update on 15th June 2012) or from publications and were used for genetic analyses. The association of different alleles of pfnhe-1 with resistance to quinoline antimalarial drugs showed marked geographic disparities. The validity and reliability of candidate polymorphisms in pfnhe-1 gene as molecular markers of QNR appeared restricted to endemic areas from South Asia or possibly East African countries and needs to be confirmed.
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Affiliation(s)
- Didier Ménard
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | | | - Nimol Khim
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Arsène Ratsimbasoa
- Ministère de la Santé, du Planning Familial et de la Protection Sociale, Programme National de Lutte contre le Paludisme, BP 1869 Antananarivo, Madagascar
| | - Benoit Witkowski
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Christophe Benedet
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Lydie Canier
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Odile Mercereau-Puijalon
- Unité d'Immunologie Moléculaire des Parasites, Institut Pasteur & Centre National de la Recherche Scientifique, Unité de Recherche Associée 2581, Paris, France
| | - Rémy Durand
- Laboratoire de Parasitologie-Mycologie, Hôpital Avicenne, AP-HP, Bobigny, France
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Griffin CE, Hoke JM, Samarakoon U, Duan J, Mu J, Ferdig MT, Warhurst DC, Cooper RA. Mutation in the Plasmodium falciparum CRT protein determines the stereospecific activity of antimalarial cinchona alkaloids. Antimicrob Agents Chemother 2012; 56:5356-64. [PMID: 22869567 PMCID: PMC3457399 DOI: 10.1128/aac.05667-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 07/30/2012] [Indexed: 11/20/2022] Open
Abstract
The Cinchona alkaloids are quinoline aminoalcohols that occur as diastereomer pairs, typified by (-)-quinine and (+)-quinidine. The potency of (+)-isomers is greater than the (-)-isomers in vitro and in vivo against Plasmodium falciparum malaria parasites. They may act by the inhibition of heme crystallization within the parasite digestive vacuole in a manner similar to chloroquine. Earlier studies showed that a K76I mutation in the digestive vacuole-associated protein, PfCRT (P. falciparum chloroquine resistance transporter), reversed the normal potency order of quinine and quinidine toward P. falciparum. To further explore PfCRT-alkaloid interactions in the malaria parasite, we measured the in vitro susceptibility of eight clonal lines of P. falciparum derived from the 106/1 strain, each containing a unique pfcrt allele, to four Cinchona stereoisomer pairs: quinine and quinidine; cinchonidine and cinchonine; hydroquinine and hydroquinidine; 9-epiquinine and 9-epiquinidine. Stereospecific potency of the Cinchona alkaloids was associated with changes in charge and hydrophobicity of mutable PfCRT amino acids. In isogenic chloroquine-resistant lines, the IC(50) ratio of (-)/(+) CA pairs correlated with side chain hydrophobicity of the position 76 residue. Second-site PfCRT mutations negated the K76I stereospecific effects: charge-change mutations C72R or Q352K/R restored potency patterns similar to the parent K76 line, while V369F increased susceptibility to the alkaloids and nullified stereospecific differences between alkaloid pairs. Interactions between key residues of the PfCRT channel/transporter with (-) and (+) alkaloids are stereospecifically determined, suggesting that PfCRT binding plays an important role in the antimalarial activity of quinine and other Cinchona alkaloids.
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Affiliation(s)
- Carol E. Griffin
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA
| | - Jonathan M. Hoke
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA
| | - Upeka Samarakoon
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, South Bend, Indiana, USA
| | - Junhui Duan
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Jianbing Mu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Michael T. Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, South Bend, Indiana, USA
| | - David C. Warhurst
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Roland A. Cooper
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA
- Department of Natural Sciences and Mathematics, Dominican University of California, San Rafael, California, USA
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Brown T, Smith LS, Oo EKS, Shawng K, Lee TJ, Sullivan D, Beyrer C, Richards AK. Molecular surveillance for drug-resistant Plasmodium falciparum in clinical and subclinical populations from three border regions of Burma/Myanmar: cross-sectional data and a systematic review of resistance studies. Malar J 2012; 11:333. [PMID: 22992214 PMCID: PMC3518194 DOI: 10.1186/1475-2875-11-333] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 08/15/2012] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Confirmation of artemisinin-delayed parasite clearance in Plasmodium falciparum along the Thai-Myanmar border has inspired a global response to contain and monitor drug resistance to avert the disastrous consequences of a potential spread to Africa. However, resistance data from Myanmar are sparse, particularly from high-risk areas where limited health services and decades of displacement create conditions for resistance to spread. Subclinical infections may represent an important reservoir for resistance genes that confer a fitness disadvantage relative to wild-type alleles. This study estimates the prevalence of resistance genotypes in three previously unstudied remote populations in Myanmar and tests the a priori hypothesis that resistance gene prevalence would be higher among isolates collected from subclinical infections than isolates collected from febrile clinical patients. A systematic review of resistance studies is provided for context. METHODS Community health workers in Karen and Kachin States and an area spanning the Indo-Myanmar border collected dried blood spots from 988 febrile clinical patients and 4,591 villagers with subclinical infection participating in routine prevalence surveys. Samples positive for P. falciparum 18 s ribosomal RNA by real-time PCR were genotyped for P. falciparum multidrug resistance protein (pfmdr1) copy number and the pfcrt K76T polymorphism using multiplex real-time PCR. RESULTS Pfmdr1 copy number increase and the pfcrt K76 polymorphism were determined for 173 and 269 isolates, respectively. Mean pfmdr1 copy number was 1.2 (range: 0.7 to 3.7). Pfmdr1 copy number increase was present in 17.5%, 9.6% and 11.1% of isolates from Karen and Kachin States and the Indo-Myanmar border, respectively. Pfmdr1 amplification was more prevalent in subclinical isolates (20.3%) than clinical isolates (6.4%, odds ratio 3.7, 95% confidence interval 1.1 - 12.5). Pfcrt K76T prevalence ranged from 90-100%. CONCLUSIONS Community health workers can contribute to molecular surveillance of drug resistance in remote areas of Myanmar. Marginal and displaced populations under-represented among previous resistance investigations can and should be included in resistance surveillance efforts, particularly once genetic markers of artemisinin-delayed parasite clearance are identified. Subclinical infections may contribute to the epidemiology of drug resistance, but determination of gene amplification from desiccated filter samples requires further validation when DNA concentration is low.
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Affiliation(s)
- Tyler Brown
- Johns Hopkins University School of Medicine, Broadway Research Building, 733 N. Broadway, Suite 147, Baltimore, MD, 21205, USA
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
| | - Linda S Smith
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
| | - Eh Kalu Shwe Oo
- Karen Department of Health and Welfare, PO Box 189, Mae Sot, Tak, 63110, Thailand
| | - Kum Shawng
- Office of the Director of the Health Department, Kachin Baptist Convention 135/Shan Su (South), Myitkyina, Kachin State, Myanmar
| | - Thomas J Lee
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
- School of Medicine, University of California at Los Angeles, 924 Westwood Blvd, Suite 300, Los Angeles, CA, 90024, USA
| | - David Sullivan
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health 615 North Wolfe St, Room E5628, Baltimore, MD, 21205, USA
| | - Chris Beyrer
- Department of Epidemiology Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St., Suite E7152, Baltimore, MD, 21205, USA
| | - Adam K Richards
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
- Department of General Internal Medicine and Health Services Research, University of California at Los Angeles, 911 Broxton Ave, Los Angeles, CA, 90025, USA
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Parker D, Lerdprom R, Srisatjarak W, Yan G, Sattabongkot J, Wood J, Sirichaisinthop J, Cui L. Longitudinal in vitro surveillance of Plasmodium falciparum sensitivity to common anti-malarials in Thailand between 1994 and 2010. Malar J 2012; 11:290. [PMID: 22908880 PMCID: PMC3472280 DOI: 10.1186/1475-2875-11-290] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 07/22/2012] [Indexed: 11/23/2022] Open
Abstract
Background Drug and multidrug-resistant Plasmodium falciparum malaria has existed in Thailand for several decades. Furthermore, Thailand serves as a sentinel for drug-resistant malaria within the Greater Mekong sub-region. However, the drug resistance situation is highly dynamic, changing quickly over time. Here parasite in vitro drug sensitivity is reported for artemisinin derivatives, mefloquine, chloroquine and quinine, across Thailand. Methods Blood was drawn from patients infected with P. falciparum in seven sentinel provinces along Thai international borders with Cambodia, Myanmar, Laos, and Malaysia. In vitro parasite sensitivity was tested using the World Health Organization’s microtest (mark III) (between 1994 and 2002) and the histidine-rich protein-2 (HRP2)-based enzyme-linked immunosorbent assay (in 2010). Following World Health Organization protocol, at least 30 isolates were collected for each province and year represented in this study. Where possible, t-tests were used to test for significant differences. Results There appears to be little variation across study sites with regard to parasite sensitivity to chloroquine. Quinine resistance appears to have been rising prior to 1997, but has subsequently decreased. Mefloquine sensitivity appears high across the provinces, especially along the north-western border with Myanmar and the eastern border with Cambodia. Finally, the data suggest that parasite sensitivity to artemisinin and its derivatives is significantly higher in provinces along the north-western border with Myanmar. Conclusions Parasite sensitivity to anti-malarials in Thailand is highly variable over time and largely mirrors official drug use policy. The findings with regard to reduced sensitivity to artemisinin derivatives are supported by recent reports of reduced parasite clearance associated with artemisinin. This trend is alarming since artemisinin is considered the last defence against malaria. Continued surveillance in Thailand, along with increased collaboration and surveillance across the entire Greater Mekong sub-region, is clearly warranted.
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Affiliation(s)
- Daniel Parker
- Department of Anthropology, The Pennsylvania State University, 409 Carpenter Building, University Park, PA 16802, USA
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