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Mukhongo HN, Kinyua JK, Weldemichael YG, Kasili RW. Screening for antifolate and artemisinin resistance in Plasmodium falciparum dried-blood spots from three hospitals of Eritrea. F1000Res 2024; 10:628. [PMID: 38840941 PMCID: PMC11150900 DOI: 10.12688/f1000research.54195.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/11/2024] [Indexed: 06/07/2024] Open
Abstract
Background Antimalarial drug resistance is a major challenge hampering malaria control and elimination. About three-quarters of Eritrea's population resides in the malaria-endemic western lowlands of the country. Plasmodium falciparum, the leading causative parasite species, has developed resistance to basically all antimalarials. Continued surveillance of drug resistance using genetic markers provides important molecular data for treatment policies which complements clinical studies, and strengthens control efforts. This study sought to genotype point mutations associated with P. falciparum resistance to sulfadoxine-pyrimethamine and artemisinin, in dried-blood spots from three hospitals in the western lowlands of Eritrea. Methods Dried-blood spot samples were collected from patients visiting Adi Quala, Keren and Gash Barka Hospitals, between July and October, 2014. The patients were followed up after treatment with first line artesunate-amodiaquine, and dried-blood spots were collected on day three after treatment. Nested polymerase chain reaction and Sanger sequencing techniques were employed to genotype point mutations in the Pfdhfr (PF3D7_0417200), Pfdhps (PF3D7_0810800) and PfK13 (PF3D7_1343700) partial gene regions. Results Sequence data analyses of PCR-positive isolates found wild-type artemisinin haplotypes associated with resistance (Y493Y, R539R, I543I) in three isolates, whereas four mutant antifolate haplotypes associated with resistance were observed in six isolates. These included the triple-mutant Pfdhfr (S108N, C59R, N51I) haplotype, the double-mutant Pfdhfr (N51I, S108N) haplotype, the single-mutant Pfdhfr (K540E) haplotype, and the mixed-mutant Pfdhfr-Pfdhps (S108N, N51I + K540E) haplotype. Other findings observed were, a rare non-synonymous Pfdhfr V45A mutation in four isolates, and a synonymous Pfdhps R449R in one isolate. Conclusions The mutant antifolate haplotypes observed indicate a likely existence of full SP resistance. Further studies can be carried out to estimate the prevalence of SP resistance. The wild-type artemisinin haplotypes observed suggest artemisinin is still an effective treatment. Continuous monitoring of point mutations associated with delayed parasite clearance in ART clinical studies is recommended.
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Affiliation(s)
- Harriet Natabona Mukhongo
- College of Health Sciences; Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Juja, P.O. Box 62000-00200, Nairobi, Kenya
| | - Johnson Kang'ethe Kinyua
- College of Health Sciences; Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Juja, P.O. Box 62000-00200, Nairobi, Kenya
| | - Yishak Gebrekidan Weldemichael
- College of Science; Department of Biology, Eritrea Institute of Technology, Asmara, P.O. Box 12676, Mai-Nefhi, Asmara, Eritrea
| | - Remmy Wekesa Kasili
- Institute of Biotechnology Research, Jomo Kenyatta University of Agriculture and Technology, Juja, P.O. Box 62000-00200, Nairobi, Kenya
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Yan H, Feng J, Yin JH, Huang F, Kong XL, Lin KM, Zhang T, Feng XY, Zhou SS, Cao JP, Xia ZG. High Frequency Mutations in pfdhfr and pfdhps of Plasmodium falciparum in Response to Sulfadoxine-Pyrimethamine: A Cross-Sectional Survey in Returning Chinese Migrants From Africa. Front Cell Infect Microbiol 2021; 11:673194. [PMID: 34568082 PMCID: PMC8456993 DOI: 10.3389/fcimb.2021.673194] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 06/14/2021] [Indexed: 11/13/2022] Open
Abstract
Background Sulfadoxine-pyrimethamine (SP) is recommended for intermittent preventive treatment in Africa against Plasmodium falciparum infection. However, increasing SP resistance (SPR) of P. falciparum affects the therapeutic efficacy of SP, and pfdhfr (encoding dihydrofolate reductase) and pfdhps (encoding dihydropteroate synthase) genes are widely used as molecular markers for SPR surveillance. In the present study, we analyzed single nucleotide polymorphisms (SNPs) of pfdhfr and pfdhps in P. falciparum isolated from infected Chinese migrant workers returning from Africa. Methods In total, 159 blood samples from P. falciparum-infected workers who had returned from Africa to Anhui, Shangdong, and Guangxi provinces were successfully detected and analyzed from 2017 to 2019. The SNPs in pfdhfr and pfdhps were analyzed using nested PCR. The genotypes and linkage disequilibrium (LD) were analyzed using Haploview. Results High frequencies of the Asn51Ile (N51I), Cys59Arg(C59R), and Ser108Asn(S108N) mutant alleles were observed, with mutation frequencies of 97.60, 87.43, and 97.01% in pfdhfr, respectively. A triple mutation (IRN) in pfdhfr was the most prevalent haplotype (86.83%). Six point mutations were detected in pfdhps DNA fragment, Ile431Val (I431V), Ser436Ala (S436A), Ala437Gly (A437G), Lys540Glu(K540E), Ala581Gly(A581G), Ala613Ser(A613S). The pfdhps K540E (27.67%) was the most predominant allele, followed by S436A (27.04%), and a single mutant haplotype (SGKAA; 62.66%) was predominant in pfdhps. In total, 5 haplotypes of the pfdhfr gene and 13 haplotypes of the pfdhps gene were identified. A total of 130 isolates with 12 unique haplotypes were found in the pfdhfr-pfdhps combined haplotypes, most of them (n = 85, 65.38%) carried quadruple allele combinations (CIRNI-SGKAA). Conclusion A high prevalence of point mutations in the pfdhfr and pfdhps genes of P. falciparum isolates was detected among Chinese migrant workers returning from Africa. Therefore, continuous in vitro molecular monitoring of Sulfadoxine-Pyrimethemine combined in vivo therapeutic monitoring of artemisinin combination therapy (ACT) efficacy and additional control efforts among migrant workers are urgently needed.
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Affiliation(s)
- He Yan
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
| | - Jun Feng
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China.,School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian-Hai Yin
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
| | - Fang Huang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
| | - Xiang-Li Kong
- Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Shandong, China
| | - Kang-Ming Lin
- Instit of Parasitic Diseases, Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Guangxi, China
| | - Tao Zhang
- Anhu Provincial Center for Disease Control and Prevention, Anhui, China
| | - Xin-Yu Feng
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
| | - Shui-Sen Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
| | - Jian-Ping Cao
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China.,School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhi-Gui Xia
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
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Niba PTN, Nji AM, Evehe MS, Ali IM, Netongo PM, Ngwafor R, Moyeh MN, Ngum LN, Ndum OE, Acho FA, Mbu'u CM, Fosah DA, Atogho-Tiedeu B, Achonduh-Atijegbe O, Djokam-Dadjeu R, Chedjou JPK, Bigoga JD, Moukoko CEE, Ajua A, Achidi E, Tallah E, Leke RGF, Tourgordi A, Ringwald P, Alifrangis M, Mbacham WF. Drug resistance markers within an evolving efficacy of anti-malarial drugs in Cameroon: a systematic review and meta-analysis (1998-2020). Malar J 2021; 20:32. [PMID: 33422080 PMCID: PMC7796563 DOI: 10.1186/s12936-020-03543-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/10/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Malaria remains highly endemic in Cameroon. The rapid emergence and spread of drug resistance was responsible for the change from monotherapies to artemisinin-based combinations. This systematic review and meta-analysis aimed to determine the prevalence and distribution of Plasmodium falciparum drug resistance markers within an evolving efficacy of anti-malarial drugs in Cameroon from January 1998 to August 2020. METHODS The PRISMA-P and PRISMA statements were adopted in the inclusion of studies on single nucleotide polymorphisms (SNPs) of P. falciparum anti-malarial drug resistance genes (Pfcrt, Pfmdr1, Pfdhfr, Pfdhps, Pfatp6, Pfcytb and Pfk13). The heterogeneity of the included studies was evaluated using the Cochran's Q and I2 statistics. The random effects model was used as standard in the determination of heterogeneity between studies. RESULTS Out of the 902 records screened, 48 studies were included in this aggregated meta-analysis of molecular data. A total of 18,706 SNPs of the anti-malarial drug resistance genes were genotyped from 47,382 samples which yielded a pooled prevalence of 35.4% (95% CI 29.1-42.3%). Between 1998 and 2020, there was significant decline (P < 0.0001 for all) in key mutants including Pfcrt 76 T (79.9%-43.0%), Pfmdr1 86Y (82.7%-30.5%), Pfdhfr 51I (72.2%-66.9%), Pfdhfr 59R (76.5%-67.8%), Pfdhfr 108 N (80.8%-67.6%). The only exception was Pfdhps 437G which increased over time (30.4%-46.9%, P < 0.0001) and Pfdhps 540E that remained largely unchanged (0.0%-0.4%, P = 0.201). Exploring mutant haplotypes, the study observed a significant increase in the prevalence of Pfcrt CVIET mixed quintuple haplotype from 57.1% in 1998 to 57.9% in 2020 (P < 0.0001). In addition, within the same study period, there was no significant change in the triple Pfdhfr IRN mutant haplotype (66.2% to 67.3%, P = 0.427). The Pfk13 amino acid polymorphisms associated with artemisinin resistance were not detected. CONCLUSIONS This review reported an overall decline in the prevalence of P. falciparum gene mutations conferring resistance to 4-aminoquinolines and amino alcohols for a period over two decades. Resistance to artemisinins measured by the presence of SNPs in the Pfk13 gene does not seem to be a problem in Cameroon. Systematic review registration PROSPERO CRD42020162620.
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Affiliation(s)
- Peter Thelma Ngwa Niba
- MARCAD-DELTAS Programme, Laboratory for Public Health Research Biotechnologies, University of Yaoundé I, Yaoundé, Cameroon
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Akindeh M Nji
- MARCAD-DELTAS Programme, Laboratory for Public Health Research Biotechnologies, University of Yaoundé I, Yaoundé, Cameroon
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Marie-Solange Evehe
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Innocent M Ali
- MARCAD-DELTAS Programme, Laboratory for Public Health Research Biotechnologies, University of Yaoundé I, Yaoundé, Cameroon
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Palmer Masumbe Netongo
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Randolph Ngwafor
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- National Malaria Control Programme, Ministry of Public Health, Yaoundé, Cameroon
| | - Marcel N Moyeh
- MARCAD-DELTAS Programme, Laboratory for Public Health Research Biotechnologies, University of Yaoundé I, Yaoundé, Cameroon
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Lesley Ngum Ngum
- MARCAD-DELTAS Programme, Laboratory for Public Health Research Biotechnologies, University of Yaoundé I, Yaoundé, Cameroon
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon
- Institute of Medical Research and Medicinal Plant Studies, Ministry of Scientific Research and Innovation, Yaoundé, Cameroon
| | - Oliva Ebie Ndum
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Université Des Montagnes, Banganté, West Region, Cameroon
| | - Fon Abongwa Acho
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
| | - Cyrille Mbanwi Mbu'u
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Microbiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Dorothy A Fosah
- National Malaria Control Programme, Ministry of Public Health, Yaoundé, Cameroon
| | - Barbara Atogho-Tiedeu
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | | | - Rosine Djokam-Dadjeu
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Jean Paul Kengne Chedjou
- MARCAD-DELTAS Programme, Laboratory for Public Health Research Biotechnologies, University of Yaoundé I, Yaoundé, Cameroon
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Jude D Bigoga
- MARCAD-DELTAS Programme, Laboratory for Public Health Research Biotechnologies, University of Yaoundé I, Yaoundé, Cameroon
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Carole Else Eboumbou Moukoko
- Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Malaria Research Service, Centre Pasteur Cameroon, Yaoundé, Cameroon
| | - Anthony Ajua
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Eric Achidi
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Esther Tallah
- Malaria Consortium-Cameroon Coalition Against Malaria, Yaoundé, Cameroon
| | - Rose G F Leke
- MARCAD-DELTAS Programme, Laboratory for Public Health Research Biotechnologies, University of Yaoundé I, Yaoundé, Cameroon
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Malaria Consortium-Cameroon Coalition Against Malaria, Yaoundé, Cameroon
| | - Alexis Tourgordi
- The Cameroon Office of the World Health Organization, Yaoundé, Cameroon
| | - Pascal Ringwald
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Michael Alifrangis
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Wilfred F Mbacham
- MARCAD-DELTAS Programme, Laboratory for Public Health Research Biotechnologies, University of Yaoundé I, Yaoundé, Cameroon.
- The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon.
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.
- Malaria Consortium-Cameroon Coalition Against Malaria, Yaoundé, Cameroon.
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Abdifatah AJ, Wanna C, Kesara NB. Plasmodium falciparum drug resistance gene status in the Horn of Africa: A systematic review. ACTA ACUST UNITED AC 2018. [DOI: 10.5897/ajpp2018.4942] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Kakar Q, Sheikh S, Ahmed I, Khan MA, Jamil M, ElMohammady H, Warsame M. Efficacy of artemisinin-based combination therapies for the treatment of falciparum malaria in Pakistan (2007-2015): In vivo response and dhfr and dhps mutations. Acta Trop 2016; 164:17-22. [PMID: 27515812 DOI: 10.1016/j.actatropica.2016.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 10/21/2022]
Abstract
Artesunate+sulfadoxine-pyrimethamine (AS+SP) and artemether+lumefantrine (AL) are the first- and second line treatments, respectively, for the treatment of falciparum infections and dihydroartemsinin+piperaquine (DHA+PPQ) is a potential candidate in case AS+SP or AL fails in Pakistan. The therapeutic efficacies of AS+SP (5 sites in 2007, 2 sites in 2011 and 2 sites in 2012), AL (2 sites in 2012) and DHA+PPQ (2 sites in 2015) were evaluated in seven sentinel sites. Clinical and parasitological outcomes were evaluated among eligible patients. Mutations of the P. falciparum dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes were investigated. After PCR correction, a 98.5-100% adequate clinical and parasitological response (ACPR) for AS+SP and a 98.8-100% ACPR for AL were observed by day 28, as well as a 100% ACPR by day 42 for DHA+PPQ. The prevalences of mutants dhfr S108N (100%) and C59R (98%-100%) reached or were near fixation. The double dhfr (C59R/S108N) mutant was dominant (96%-100%) at all sites. The triple dhfr (N51I/C59R/S108N) mutant was rare (1.1%-2.3%). The prevalence of dhps A437G varied between 38% and 70%. A combination of triple dhfr/dhps (C59R/S108N+A437G or N51I/S108N+A437G) mutants was observed (38%-69%). A quadruple dhfr/dhps (N51I/C59R/S108N+A437G) mutation was very rare and no quintuple (N51I/C59R/S108N+A437G/K540E) mutations were detected. AS+SP remains highly effective in Pakistan. However, molecular data indicate that SP resistance is being established, although mutations that confer a high risk of SP treatment failure are rare or non-existent. This underscores the need for close monitoring of both in vivo AS+SP efficacy and dhfr and dhps mutations to inform national treatment policy. Trial registration numbers: ISRCTN21926128 (2007), ACTRN12611001244998 (2011), ACTRN12612001090808 (2012), ACTRN12615001248550 (2015).
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Chauvin P, Menard S, Iriart X, Nsango SE, Tchioffo MT, Abate L, Awono-Ambéné PH, Morlais I, Berry A. Prevalence of Plasmodium falciparum parasites resistant to sulfadoxine/pyrimethamine in pregnant women in Yaoundé, Cameroon: emergence of highly resistant pfdhfr/pfdhps alleles. J Antimicrob Chemother 2015; 70:2566-71. [PMID: 26080363 DOI: 10.1093/jac/dkv160] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 05/22/2015] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES To determine, 6 years after the adoption of intermittent preventive treatment of pregnant women with sulfadoxine/pyrimethamine (IPTp-SP) in Cameroon, (i) the polymorphism and prevalence of Plasmodium falciparum dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) gene mutations associated with sulfadoxine/pyrimethamine resistance and (ii) the consequences of sulfadoxine/pyrimethamine use in the selection of pfdhfr/pfdhps alleles. METHODS pfdhfr and pfdhps genes from P. falciparum isolates collected in Yaoundé (Cameroon) from pregnant women with symptomatic malaria before taking IPTp-SP [SP- group (control) (n = 51)] or afterwards [SP+ group (n = 49)] were sequenced. RESULTS The pfdhfr N51I, C59R, S108N triple mutant had a prevalence close to 100% (96/100) and no mutations at codons 50 and 164 were detected in either of the groups. The most frequent pfdhps mutation was A437G with a prevalence of 76.5% (39/51) in the SP- group, which was significantly higher in pregnant women who took sulfadoxine/pyrimethamine [95.9% (47/49)] (P = 0.012). Our study confirmed the presence of the pfdhps K540E mutation in Cameroon, but it remained rare. The prevalence of pfdhps A581G and A613S mutations had increased [5.9% (3/51) and 11.8% (6/51) in the control group, respectively] since the last studies in 2005. Surprisingly, the new pfdhps I431V mutation was detected, at a prevalence of 9.8% (5/51), and was found to be associated with other pfdhfr/pfdhps alleles to form an octuple N51I, C59R, S108N/I431V, S436A, A437G, A581G, A613S mutant. CONCLUSIONS Significant changes were found in pfdhps polymorphism. In particular, we observed several parasites carrying eight mutations in pfdhfr/pfdhps genes, which are very susceptible to having a high level of resistance to sulfadoxine/pyrimethamine.
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Affiliation(s)
- Pamela Chauvin
- Service de Parasitologie-Mycologie, CHU Toulouse, Toulouse, France
| | - Sandie Menard
- Centre de Physiopathologie de Toulouse Purpan, INSERM U1043, CNRS UMR5282, Université de Toulouse, Toulouse, France
| | - Xavier Iriart
- Service de Parasitologie-Mycologie, CHU Toulouse, Toulouse, France Centre de Physiopathologie de Toulouse Purpan, INSERM U1043, CNRS UMR5282, Université de Toulouse, Toulouse, France
| | - Sandrine E Nsango
- Faculté de Médecine et des Sciences Pharmaceutiques, Université de Douala, Douala, Cameroon Laboratoire d'Entomologie Médicale, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon
| | - Majoline T Tchioffo
- Laboratoire d'Entomologie Médicale, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon UMR MIVEGEC, IRD, 224-CNR, 5290-UM1-UM2, Institut de Recherche pour le Développement, Montpellier, France
| | - Luc Abate
- UMR MIVEGEC, IRD, 224-CNR, 5290-UM1-UM2, Institut de Recherche pour le Développement, Montpellier, France
| | - Parfait H Awono-Ambéné
- Laboratoire d'Entomologie Médicale, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon
| | - Isabelle Morlais
- Laboratoire d'Entomologie Médicale, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon UMR MIVEGEC, IRD, 224-CNR, 5290-UM1-UM2, Institut de Recherche pour le Développement, Montpellier, France
| | - Antoine Berry
- Service de Parasitologie-Mycologie, CHU Toulouse, Toulouse, France Centre de Physiopathologie de Toulouse Purpan, INSERM U1043, CNRS UMR5282, Université de Toulouse, Toulouse, France
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Warsame M, Hassan AM, Barrette A, Jibril AM, Elmi HH, Arale AM, Mohammady HE, Nada RA, Amran JGH, Muse A, Yusuf FE, Omar AS. Treatment of uncomplicated malaria with artesunate plus sulfadoxine-pyrimethamine is failing in Somalia: evidence from therapeutic efficacy studies andPfdhfrandPfdhpsmutant alleles. Trop Med Int Health 2015; 20:510-7. [DOI: 10.1111/tmi.12458] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marian Warsame
- Global Malaria Programme; World Health Organization; Geneva Switzerland
| | | | - Amy Barrette
- Global Malaria Programme; World Health Organization; Geneva Switzerland
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Abstract
Malaria is a leading cause of mortality worldwide and accurate diagnostic testing for malaria can potentially save an estimated 100,000 lives annually. New technologies have the potential to circumvent limitations of the traditional diagnostic method, light microscopy, which is labor intensive and requires considerable technician expertise. Immunochromatographic tests, which are easy to use in field conditions and relatively inexpensive, offer a potential solution to the problem of malaria overtreatment in resource-poor endemic countries. Assays based on the PCR are highly sensitive, can be used for unambiguous species identification and, thus, may increasingly complement or even replace light microscopy in developed countries. Experimental diagnostics using flow cytometry and mass spectrometry are currently under investigation for high-throughput screening.
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Affiliation(s)
- Michael Hawkes
- Pediatric Infectious Diseases, University of Toronto, MaRS Centre, Toronto Medical Discovery Tower, Toronto, Ontario, Canada.
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Ndiaye D, Dieye B, Ndiaye YD, Van Tyne D, Daniels R, Bei AK, Mbaye A, Valim C, Lukens A, Mboup S, Ndir O, Wirth DF, Volkman S. Polymorphism in dhfr/dhps genes, parasite density and ex vivo response to pyrimethamine in Plasmodium falciparum malaria parasites in Thies, Senegal. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2013; 3:135-42. [PMID: 24533303 PMCID: PMC3862402 DOI: 10.1016/j.ijpddr.2013.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/19/2013] [Accepted: 07/21/2013] [Indexed: 11/14/2022]
Abstract
Prevalence of dhfr/dhps mutations increased significantly between 2003 and 2011. Triple mutant dhfr 51I/59R/108N increased, from 40% in 2003 to 93% in 2011. Quadruple mutant dhfr and dhps 437G increased, from 20% to 66% then down. A strong correlation between ex vivo response to pyrimethamine and dhfr genotype.
Resistance to sulfadoxine–pyrimethamine (SP) in Plasmodium falciparum malaria parasites is associated with mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes, and these mutations have spread resistance worldwide. SP, used for several years in Senegal, has been recommended for intermittent preventive treatment for malaria in pregnancy (IPTp) and has been widely implemented since 2003 in this country. There is currently limited data on SP resistance from molecular marker genotyping, and no data on pyrimethamine ex vivo sensitivity in Senegal. Molecular markers of SP resistance and pyrimethamine ex vivo sensitivity were investigated in 416 parasite samples collected from the general population, from the Thies region between 2003 and 2011. The prevalence of the N51I/C59R/S108N triple mutation in dhfr increased from 40% in 2003 to 93% in 2011. Furthermore, the prevalence of the dhfr N51I/C59R/S108N and dhps A437G quadruple mutation increased, from 20% to 66% over the same time frame, then down to 44% by 2011. There was a significant increase in the prevalence of the dhfr triple mutation, as well as an association between dhfr genotypes and pyrimethamine response. Conversely, dhps mutations in codons 436 and 437 did not show consistent variation between 2003 and 2011. These findings suggest that regular screening for molecular markers of antifolate resistance and ex vivo drug response monitoring should be incorporated with ongoing in vivo efficacy monitoring in areas where IPTp-SP is implemented and where pyrimethamine and sulfa drugs are still widely administered in the general population.
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Affiliation(s)
- Daouda Ndiaye
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Baba Dieye
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Yaye D Ndiaye
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Daria Van Tyne
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Rachel Daniels
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Amy K Bei
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Aminata Mbaye
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Clarissa Valim
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Amanda Lukens
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Souleymane Mboup
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Omar Ndir
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Sarah Volkman
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
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Abdul-Ghani R, Farag HF, Allam AF. Sulfadoxine-pyrimethamine resistance in Plasmodium falciparum: a zoomed image at the molecular level within a geographic context. Acta Trop 2013; 125:163-90. [PMID: 23131424 DOI: 10.1016/j.actatropica.2012.10.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 10/25/2012] [Accepted: 10/26/2012] [Indexed: 10/27/2022]
Abstract
Antimalarial chemotherapy is one of the main pillars in the prevention and control of malaria. Following widespread resistance of Plasmodium falciparum to chloroquine, sulfadoxine-pyrimethamine came to the scene as an alternative to the cheap and well-tolerated chloroquine. However, widespread resistance to sulfadoxine-pyrimethamine has been documented. In vivo efficacy tests are the gold standard for assessing drug resistance and treatment failure. However, they have many disadvantages, such as influence of host immunity and drug pharmacokinetics. In vitro tests of antimalarial drug efficacy also have many technical difficulties. Molecular markers of resistance have emerged as epidemiologic tools to investigate antimalarial drug resistance even before becoming clinically evident. Mutations in P. falciparum dihydrofolate reductase and dihydrofolate synthase have been extensively studied as molecular markers for resistance to pyrimethamine and sulfadoxine, respectively. This review highlights the resistance of P. falciparum at the molecular level presenting both supporting and opposing studies on the utility of molecular markers.
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Pearce RJ, Ord R, Kaur H, Lupala C, Schellenberg J, Shirima K, Manzi F, Alonso P, Tanner M, Mshinda H, Roper C, Schellenberg D. A community-randomized evaluation of the effect of intermittent preventive treatment in infants on antimalarial drug resistance in southern Tanzania. J Infect Dis 2012; 207:848-59. [PMID: 23225897 DOI: 10.1093/infdis/jis742] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Intermittent preventive treatment in infants (IPTi) is the administration of sulfadoxine-pyrimethamine (SP) at 2, 3, and 9 months of age to prevent malaria. We investigated the influence of IPTi on drug resistance. METHODS Twenty-four areas were randomly assigned to receive or not receive IPTi. Blood collected during representative household surveys at baseline and 15 and 27 months after implementation was tested for SP and resistance markers. RESULTS The frequency of SP in blood was similar in the IPTi and comparison areas at baseline and at 15 months. dhfr and dhps mutations were also similar at baseline and then increased similarly in both arms after 15 months of SP-IPTi. First-line treatment was switched from SP to artemether-lumefantrine before the final survey, when SP positivity fell among infants in comparison areas but increased in IPTi areas. This was accompanied by an increase in dhfr but not dhps mutations in IPTi areas (P = .004 and P = .18, respectively). CONCLUSIONS IPTi did not increase drug pressure or the selection on dhfr and dhps mutants, when SP was the first-line malaria treatment. Introduction of artemether-lumefantrine was followed by an increase in dhfr mutations, consistent with weak selection attributable to SP-IPTi, but not by an increase in dhps mutations, suggesting a fitness cost of this mutation.
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Affiliation(s)
- Richard J Pearce
- London School of Hygiene and Tropical Medicine, London, United Kingdom
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Villa A, Carmona-Fonseca J, Benito A, Martínez A, Maestre A. Status of dhps and dhfr genes of Plasmodium falciparum in Colombia before artemisinin based treatment policy. INFECTIO 2012. [DOI: 10.1016/s0123-9392(12)70056-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Molecular Approaches for Diagnosis of Malaria and Characterization of Genetic Markers of Drug Resistance. Mol Microbiol 2011. [DOI: 10.1128/9781555816834.ch46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Ballif M, Hii J, Marfurt J, Crameri A, Fafale A, Felger I, Beck HP, Genton B. Monitoring of malaria parasite resistance to chloroquine and sulphadoxine-pyrimethamine in the Solomon Islands by DNA microarray technology. Malar J 2010; 9:270. [PMID: 20925934 PMCID: PMC2959069 DOI: 10.1186/1475-2875-9-270] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 10/06/2010] [Indexed: 11/14/2022] Open
Abstract
Background Little information is available on resistance to anti-malarial drugs in the Solomon Islands (SI). The analysis of single nucleotide polymorphisms (SNPs) in drug resistance associated parasite genes is a potential alternative to classical time- and resource-consuming in vivo studies to monitor drug resistance. Mutations in pfmdr1 and pfcrt were shown to indicate chloroquine (CQ) resistance, mutations in pfdhfr and pfdhps indicate sulphadoxine-pyrimethamine (SP) resistance, and mutations in pfATPase6 indicate resistance to artemisinin derivatives. Methods The relationship between the rate of treatment failure among 25 symptomatic Plasmodium falciparum-infected patients presenting at the clinic and the pattern of resistance-associated SNPs in P. falciparum infecting 76 asymptomatic individuals from the surrounding population was investigated. The study was conducted in the SI in 2004. Patients presenting at a local clinic with microscopically confirmed P. falciparum malaria were recruited and treated with CQ+SP. Rates of treatment failure were estimated during a 28-day follow-up period. In parallel, a DNA microarray technology was used to analyse mutations associated with CQ, SP, and artemisinin derivative resistance among samples from the asymptomatic community. Mutation and haplotype frequencies were determined, as well as the multiplicity of infection. Results The in vivo study showed an efficacy of 88% for CQ+SP to treat P. falciparum infections. DNA microarray analyses indicated a low diversity in the parasite population with one major haplotype present in 98.7% of the cases. It was composed of fixed mutations at position 86 in pfmdr1, positions 72, 75, 76, 220, 326 and 356 in pfcrt, and positions 59 and 108 in pfdhfr. No mutation was observed in pfdhps or in pfATPase6. The mean multiplicity of infection was 1.39. Conclusion This work provides the first insight into drug resistance markers of P. falciparum in the SI. The obtained results indicated the presence of a very homogenous P. falciparum population circulating in the community. Although CQ+SP could still clear most infections, seven fixed mutations associated with CQ resistance and two fixed mutations related to SP resistance were observed. Whether the absence of mutations in pfATPase6 indicates the efficacy of artemisinin derivatives remains to be proven.
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Affiliation(s)
- Marie Ballif
- Swiss Tropical and Public Health Institute, Department of Medical Parasitology and Biology of Infection, Department of Epidemiology and Public Health, Socinstrasse 57, 4002 Basel, Switzerland
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Picot S, Olliaro P, de Monbrison F, Bienvenu AL, Price RN, Ringwald P. A systematic review and meta-analysis of evidence for correlation between molecular markers of parasite resistance and treatment outcome in falciparum malaria. Malar J 2009; 8:89. [PMID: 19413906 PMCID: PMC2681474 DOI: 10.1186/1475-2875-8-89] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Accepted: 05/04/2009] [Indexed: 01/17/2023] Open
Abstract
Background An assessment of the correlation between anti-malarial treatment outcome and molecular markers would improve the early detection and monitoring of drug resistance by Plasmodium falciparum. The purpose of this systematic review was to determine the risk of treatment failure associated with specific polymorphisms in the parasite genome or gene copy number. Methods Clinical studies of non-severe malaria reporting on target genetic markers (SNPs for pfmdr1, pfcrt, dhfr, dhps, gene copy number for pfmdr1) providing complete information on inclusion criteria, outcome, follow up and genotyping, were included. Three investigators independently extracted data from articles. Results were stratified by gene, codon, drug and duration of follow-up. For each study and aggregate data the random effect odds ratio (OR) with 95%CIs was estimated and presented as Forest plots. An OR with a lower 95th confidence interval > 1 was considered consistent with a failure being associated to a given gene mutation. Results 92 studies were eligible among the selection from computerized search, with information on pfcrt (25/159 studies), pfmdr1 (29/236 studies), dhfr (18/373 studies), dhps (20/195 studies). The risk of therapeutic failure after chloroquine was increased by the presence of pfcrt K76T (Day 28, OR = 7.2 [95%CI: 4.5–11.5]), pfmdr1 N86Y was associated with both chloroquine (Day 28, OR = 1.8 [95%CI: 1.3–2.4]) and amodiaquine failures (OR = 5.4 [95%CI: 2.6–11.3, p < 0.001]). For sulphadoxine-pyrimethamine the dhfr single (S108N) (Day 28, OR = 3.5 [95%CI: 1.9–6.3]) and triple mutants (S108N, N51I, C59R) (Day 28, OR = 3.1 [95%CI: 2.0–4.9]) and dhfr-dhps quintuple mutants (Day 28, OR = 5.2 [95%CI: 3.2–8.8]) also increased the risk of treatment failure. Increased pfmdr1 copy number was correlated with treatment failure following mefloquine (OR = 8.6 [95%CI: 3.3–22.9]). Conclusion When applying the selection procedure for comparative analysis, few studies fulfilled all inclusion criteria compared to the large number of papers identified, but heterogeneity was limited. Genetic molecular markers were related to an increased risk of therapeutic failure. Guidelines are discussed and a checklist for further studies is proposed.
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Affiliation(s)
- Stéphane Picot
- Malaria Research Unit, EA 4170, University Lyon 1, Faculty of Medicine, Lyon, France.
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Multiple origins and regional dispersal of resistant dhps in African Plasmodium falciparum malaria. PLoS Med 2009; 6:e1000055. [PMID: 19365539 PMCID: PMC2661256 DOI: 10.1371/journal.pmed.1000055] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 02/13/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Although the molecular basis of resistance to a number of common antimalarial drugs is well known, a geographic description of the emergence and dispersal of resistance mutations across Africa has not been attempted. To that end we have characterised the evolutionary origins of antifolate resistance mutations in the dihydropteroate synthase (dhps) gene and mapped their contemporary distribution. METHODS AND FINDINGS We used microsatellite polymorphism flanking the dhps gene to determine which resistance alleles shared common ancestry and found five major lineages each of which had a unique geographical distribution. The extent to which allelic lineages were shared among 20 African Plasmodium falciparum populations revealed five major geographical groupings. Resistance lineages were common to all sites within these regions. The most marked differentiation was between east and west African P. falciparum, in which resistance alleles were not only of different ancestry but also carried different resistance mutations. CONCLUSIONS Resistant dhps has emerged independently in multiple sites in Africa during the past 10-20 years. Our data show the molecular basis of resistance differs between east and west Africa, which is likely to translate into differing antifolate sensitivity. We have also demonstrated that the dispersal patterns of resistance lineages give unique insights into recent parasite migration patterns.
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Alker AP, Kazadi WM, Kutelemeni AK, Bloland PB, Tshefu AK, Meshnick SR. dhfr and dhps genotype and sulfadoxine-pyrimethamine treatment failure in children with falciparum malaria in the Democratic Republic of Congo. Trop Med Int Health 2009; 13:1384-91. [PMID: 19055622 DOI: 10.1111/j.1365-3156.2008.02150.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To determine the relationship between mutations in dhfr and dhps and SP treatment failure in Plasmodium falciparum malaria in the Democratic Republic of the Congo (DRC). METHODS Therapeutic efficacy trial was conducted in Rutshuru, Eastern DRC, between June and September 2002, comparing sulfadoxine-pyrimethamine (SP), SP plus amodiaquine (AQSP) and artesunate plus SP (ASSP) regimens for treating malaria in children under 5 years old. We genotyped 212 samples for mutations associated with SP resistance and investigated their association with treatment failure. RESULTS In the SP arm, 61% of the subjects experienced treatment failure after 14 days. The failure rate was lower in the combination arms (AQSP: 32%, ASSP: 21%). The dhfr-108 and dhfr-51 mutations were nearly universal while 89% of the samples had at least one additional mutation at dhfr-59, dhps-437 or dhps-540. Dhps mutations had a bigger impact on treatment failure in children with high parasite density: for children with a parasite density <45 000 parasites/microl, the risk of treatment failure was 37% for mutations at dhps-437 and dhps-540 mutation and 21% for neither mutation [risk difference (RD) = 17%, 95% CI: -3%, 36%]. In children with a parasite density >45 000 parasites/microl, the treatment failure risk was 58% and 8% for children with both mutations or neither mutation, respectively (RD = 51%, 95% CI: 34%, 67%). CONCLUSIONS Dhps-437 and dhps-540 are strongly associated with SP treatment failure and should be evaluated further as a method for surveillance of SP-based therapy in DRC.
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Affiliation(s)
- Alisa P Alker
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC 27599, USA.
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Lynch C, Pearce R, Pota H, Cox J, Abeku TA, Rwakimari J, Naidoo I, Tibenderana J, Roper C. Emergence of a dhfr mutation conferring high-level drug resistance in Plasmodium falciparum populations from southwest Uganda. J Infect Dis 2008; 197:1598-604. [PMID: 18471065 DOI: 10.1086/587845] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The S108N, C59R, and N51I mutations in the Plasmodium falciparum gene that encodes dihydrofolate reductase, dhfr, confer resistance to pyrimethamine and are common in Africa. However, the I164L mutation, which confers high-level resistance, is rarely seen. We found a 14% prevalence of the I164L mutation among a sample of 51 patients with malaria in Kabale District in southwest Uganda in 2005 and a 4% prevalence among 72 patients with malaria in the neighboring district of Rukungiri during the same year. Surveillance at 6 sites across Uganda during 2002-2004 reported a single case of infection involving an I164L mutant, also in the southwest, suggesting that this is a regional hot spot. The spatial clustering and increasing prevalence of the I164L mutation is indicative of local transmission of the mutant. Targeted surveillance is needed to confirm the extent of the spread of the I164L mutation and to monitor the impact of I164L on the efficacy of antifolates for intermittent preventive treatment of pregnant women and/or infants with falciparum malaria.
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Affiliation(s)
- Caroline Lynch
- Disease Control and Vector Biology Unit, Department of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Mayor A, Serra‐Casas E, Sanz S, Aponte J, Macete E, Mandomando I, Puyol L, Berzosa P, Dobaño C, Aide P, Sacarlal J, Benito A, Alonso P, Menéndez C. Molecular Markers of Resistance to Sulfadoxine‐Pyrimethamine during Intermittent Preventive Treatment for Malaria in Mozambican Infants. J Infect Dis 2008; 197:1737-42. [DOI: 10.1086/588144] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Schoepflin S, Marfurt J, Goroti M, Baisor M, Mueller I, Felger I. Heterogeneous distribution of Plasmodium falciparum drug resistance haplotypes in subsets of the host population. Malar J 2008; 7:78. [PMID: 18460212 PMCID: PMC2391149 DOI: 10.1186/1475-2875-7-78] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 05/06/2008] [Indexed: 11/29/2022] Open
Abstract
Background The emergence of drug resistance is a major problem in malaria control. For mathematical modelling of the transmission and spread of drug resistance the determinant parameters need to be identified and measured. The underlying hypothesis is that mutations associated with drug resistance incur fitness costs to the parasite in absence of drug pressure. The distribution of drug resistance haplotypes in different subsets of the host population was investigated. In particular newly acquired haplotypes after radical cure were characterized and compared to haplotypes from persistent infections. Methods Mutations associated with antimalarial drug resistance were analysed in parasites from children, adults, and new infections occurring after treatment. Twenty-five known single nucleotide polymorphisms from four Plasmodium falciparum genes associated with drug resistance were genotyped by DNA chip technology. Results Haplotypes were found to differ between subsets of the host population. A seven-fold mutated haplotype was significantly reduced in adults compared to children and new infections, whereas parasites harbouring fewer mutations were more frequent in adults. Conclusion The reduced frequency of highly mutated parasites in chronic infections in adults is likely a result of fitness costs of drug resistance that increases with number of mutations and is responsible for reduced survival of mutant parasites.
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Affiliation(s)
- Sonja Schoepflin
- Swiss Tropical Institute, Department of Medical Parasitology and Infection Biology, Socinstr.57, 4002 Basel, Switzerland.
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Marfurt J, Müller I, Sie A, Oa O, Reeder JC, Smith TA, Beck HP, Genton B. The usefulness of twenty-four molecular markers in predicting treatment outcome with combination therapy of amodiaquine plus sulphadoxine-pyrimethamine against falciparum malaria in Papua New Guinea. Malar J 2008; 7:61. [PMID: 18423045 PMCID: PMC2377269 DOI: 10.1186/1475-2875-7-61] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2007] [Accepted: 04/19/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Papua New Guinea (PNG), combination therapy with amodiaquine (AQ) or chloroquine (CQ) plus sulphadoxine-pyrimethamine (SP) was introduced as first-line treatment against uncomplicated malaria in 2000. METHODS We assessed in vivo treatment failure rates with AQ+SP in two different areas in PNG and twenty-four molecular drug resistance markers of Plasmodium falciparum were characterized in pre-treatment samples. The aim of the study was to investigate the association between infecting genotype and treatment response in order to identify useful predictors of treatment failure with AQ+SP. RESULTS In 2004, Day-28 treatment failure rates for AQ+SP were 29% in the Karimui and 19% in the South Wosera area, respectively. The strongest independent predictors for treatment failure with AQ+SP were pfmdr1 N86Y (OR = 7.87, p < 0.01) and pfdhps A437G (OR = 3.44, p < 0.01). Mutations found in CQ/AQ related markers pfcrt K76T, A220S, N326D, and I356L did not help to increase the predictive value, the most likely reason being that these mutations reached almost fixed levels. Though mutations in SP related markers pfdhfr S108N and C59R were not associated with treatment failure, they increased the predictive value of pfdhps A437G. The difference in treatment failure rate in the two sites was reflected in the corresponding genetic profile of the parasite populations, with significant differences seen in the allele frequencies of mutant pfmdr1 N86Y, pfmdr1 Y184F, pfcrt A220S, and pfdhps A437G. CONCLUSION The study provides evidence for high levels of resistance to the combination regimen of AQ+SP in PNG and indicates which of the many molecular markers analysed are useful for the monitoring of parasite resistance to combinations with AQ+SP.
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Affiliation(s)
- Jutta Marfurt
- Swiss Tropical Institute, Socinstrasse 57, P,O, Box, CH-4002 Basel, Switzerland.
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Nsimba B, Guiyedi V, Mabika-Mamfoumbi M, Mourou-Mbina JR, Ngoungou E, Bouyou-Akotet M, Loembet R, Durand R, Le Bras J, Kombila M. Sulphadoxine/pyrimethamine versus amodiaquine for treating uncomplicated childhood malaria in Gabon: a randomized trial to guide national policy. Malar J 2008; 7:31. [PMID: 18267042 PMCID: PMC2276509 DOI: 10.1186/1475-2875-7-31] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Accepted: 02/12/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Gabon, following the adoption of amodiaquine/artesunate combination (AQ/AS) as first-line treatment of malaria and of sulphadoxine/pyrimethamine (SP) for preventive intermittent treatment of pregnant women, a clinical trial of SP versus AQ was conducted in a sub-urban area. This is the first study carried out in Gabon following the WHO guidelines. METHODS A random comparison of the efficacy of AQ (10 mg/kg/day x 3 d) and a single dose of SP (25 mg/kg of sulphadoxine/1.25 mg/kg of pyrimethamine) was performed in children under five years of age, with uncomplicated falciparum malaria, using the 28-day WHO therapeutic efficacy test. In addition, molecular genotyping was performed to distinguish recrudescence from reinfection and to determine the frequency of the dhps K540E mutation, as a molecular marker to predict SP-treatment failure. RESULTS The day-28 PCR-adjusted treatment failures for SP and AQ were 11.6% (8/69; 95% IC: 5.5-22.1) and 28.2% (20/71; 95% CI: 17.7-38.7), respectively This indicated that SP was significantly superior to AQ (P = 0.019) in the treatment of uncomplicated childhood malaria and for preventing recurrent infections. Both treatments were safe and well-tolerated, with no serious adverse reactions recorded. The dhps K540E mutation was not found among the 76 parasite isolates tested. CONCLUSION The level of AQ-resistance observed in the present study may compromise efficacy and duration of use of the AQ/AS combination, the new first-line malaria treatment. Gabonese policy-makers need to plan country-wide and close surveillance of AQ/AS efficacy to determine whether, and for how long, these new recommendations for the treatment of uncomplicated malaria remain valid.
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Affiliation(s)
- Basile Nsimba
- National Malaria Control Programme - Division for Disease Control, Ministry of Health, Brazzaville, Congo.
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Ndounga M, Tahar R, Basco LK, Casimiro PN, Malonga DA, Ntoumi F. Therapeutic efficacy of sulfadoxine-pyrimethamine and the prevalence of molecular markers of resistance in under 5-year olds in Brazzaville, Congo. Trop Med Int Health 2007; 12:1164-71. [PMID: 17956498 DOI: 10.1111/j.1365-3156.2007.01904.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To test the efficacy of sulfadoxine-pyremethamine (SP) monotherapy and establish the prevalence of mutations in dhfr and dhps in Brazzaville, Congo. METHOD We recruited 97 patients aged 6-59 months with uncomplicated malaria who attended Tenrikyo public health centre. Eighty-three were followed until day 28. SP efficacy was determined by the WHO 28-day test and analysis of mutations in the Plasmodium falciparum dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) genes. RESULTS There were seven (8.4%) early treatment failures, 23 late treatment failures (27.7%), nine (10.8%) late parasitological failures and 44 (53%) adequate clinical and parasitological responses (ACPR). After polymerase chain reaction (PCR) analysis of 64 available samples, the corrected results there were 44 (68.8%) ACPR and 19 recrudescent cases (31.2%). Approximately, 97.5% of samples bore the Asn51Ile mutation, 66.2% the Cys59Arg mutation and 98.8% the Ser108Asn mutation. Mutations of dhps at positions 437 (Ala-Gly) and 436 (Ser-Ala) were found in 85% and 12.5% of samples. Quadruple mutations (pfdhfr triple mutations in codons 51, 59 and 108+ pfdhps mutation in 437) were found in 42 samples (52.5%) and associated with treatment failures. CONCLUSION This high level of treatment failures and mutations in both genes calls for the urgent application of the new policy for malaria treatment to delay the spread of SP resistance.
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Affiliation(s)
- Mathieu Ndounga
- Laboratoire de Pharmacologie, Centre d'Etudes sur les Ressources Végétales, Brazzaville, Congo.
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Enevold A, Nkya WMMM, Theisen M, Vestergaard LS, Jensen AT, Staalsoe T, Theander TG, Bygbjerg IC, Alifrangis M. Potential impact of host immunity on malaria treatment outcome in Tanzanian children infected with Plasmodium falciparum. Malar J 2007; 6:153. [PMID: 18021388 PMCID: PMC2206045 DOI: 10.1186/1475-2875-6-153] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Accepted: 11/16/2007] [Indexed: 11/25/2022] Open
Abstract
Background In malaria endemic areas children may recover from malaria after chemotherapy in spite of harbouring genotypically drug-resistant Plasmodium falciparum. This phenomenon suggests that there is a synergy between drug treatment and acquired immunity. This hypothesis was examined in an area of moderately intense transmission of P. falciparum in Tanzania during a drug trail with sulphadoxine-pyrimethamine (SP) or amodiaquine (AQ). Methods One hundred children with uncomplicated malaria were treated with either SP or AQ and followed for 28 days. Mutations in parasite genes related to SP and AQ-resistance as well as human sickle cell trait and alpha-thalassaemia were determined using PCR and sequence-specific oligonucleotide probes and enzyme-linked immunosorbent assay (SSOP-ELISA), and IgG antibody responses to a panel of P. falciparum antigens were assessed and related to treatment outcome. Results Parasitological or clinical treatment failure (TF) was observed in 68% and 38% of children receiving SP or AQ, respectively. In those with adequate clinical and parasitological response (ACPR) compared to children with TF, and for both treatment regimens, prevalence and levels of anti-Glutamate-rich Protein (GLURP)-specific IgG antibodies were significantly higher (P < 0.001), while prevalence of parasite haplotypes associated with SP and AQ resistance was lower (P = 0.02 and P = 0.07, respectively). Interestingly, anti-GLURP-IgG antibodies were more strongly associated with treatment outcome than parasite resistant haplotypes, while the IgG responses to none of the other 11 malaria antigens were not significantly associated with ACPR. Conclusion These findings suggest that GLURP-specific IgG antibodies in this setting contribute to clearance of drug-resistant infections and support the hypothesis that acquired immunity enhances the clinical efficacy of drug therapy. The results should be confirmed in larger scale with greater sample size and with variation in transmission intensity.
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Affiliation(s)
- Anders Enevold
- Centre for Medical Parasitology, Institute of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
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Tahar R, Basco LK. Molecular epidemiology of malaria in Cameroon. XXVII. Clinical and parasitological response to sulfadoxine-pyrimethamine treatment and Plasmodium falciparum dihydrofolate reductase and dihydropteroate synthase alleles in Cameroonian children. Acta Trop 2007; 103:81-9. [PMID: 17640607 DOI: 10.1016/j.actatropica.2007.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Revised: 03/09/2007] [Accepted: 04/17/2007] [Indexed: 10/23/2022]
Abstract
The rapidly changing epidemiology of antifolate-resistant Plasmodium falciparum in Africa requires monitoring. The present study was designed to assess the degree of association between the clinical and parasitological response to sulfadoxine-pyrimethamine and allelic combinations of dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes. Of 357 children who completed the 14-day follow-up, an adequate clinical and parasitological response was observed in 316 patients (88.5%) and early and late failures occurred in 18 (5%) and 23 (6.4%, mostly due to recrudescence) patients, respectively. The majority of clinical isolates were characterized as "quadruple" (n=196, 55.2%; N51I-C59R-S108N in DHFR and A437G in DHPS) or "triple" mutants (n=97, 27.3%; N51I-C59R-S108N in DHFR and wild-type DHPS; S108N+N51I or C59R in DHFR and A437G in DHPS). Wild-type, single mutation, and double mutation were observed in 29, 20, and 13 parasites, respectively. The comparison of different sets of mutations and early or late failures did not reveal any molecular marker associated with treatment outcome when the follow-up period was limited to 14 days (P>0.05). In this study, the determination of dhfr-dhps genotypes was of limited value to predict the treatment outcome in individual patients, mostly due to few treatment failures and few wild-type haplotypes. Further monitoring will be required to define the relationship between clinical response to SP therapy and parasite genotypes in our epidemiological setting.
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Affiliation(s)
- Rachida Tahar
- Unité de Recherche 77 Paludologie Afro-tropicale, Institut de Recherche pour le Développement, Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, B. P. 288, Yaoundé, Cameroon
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Mbugi EV, Mutayoba BM, Malisa AL, Balthazary ST, Nyambo TB, Mshinda H. Drug resistance to sulphadoxine-pyrimethamine in Plasmodium falciparum malaria in Mlimba, Tanzania. Malar J 2006; 5:94. [PMID: 17076899 PMCID: PMC1636063 DOI: 10.1186/1475-2875-5-94] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Accepted: 10/31/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sulphadoxine-pyrimethamine (SP) has been and is currently used for treatment of uncomplicated Plasmodium falciparum malaria in many African countries. Nevertheless, the response of parasites to SP treatment has shown significant variation between individuals. METHODS The genes for dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) were used as markers, to investigate parasite resistance to SP in 141 children aged less than 5 years. Parasite DNA was extracted by Chelex method from blood samples collected and preserved on filter papers. Subsequently, polymerase chain reaction (PCR) and restriction fragment length polymorphism (PCR-RFLP) were applied to detect the SP resistance-associated point mutations on dhfr and dhps. Commonly reported point mutations at codons 51, 59, 108 and 164 in the dhfr and codons 437, 540 and 581 in the dhps domains were examined. RESULTS Children infected with parasites harbouring a range of single to quintuple dhfr/dhps mutations were erratically cured with SP. However, the quintuple dhfr/dhps mutant genotypes were mostly associated with treatment failures. High proportion of SP resistance-associated point mutations was detected in this study but the adequate clinical response (89.4%) observed clinically at day 14 of follow up reflects the role of semi-immunity protection and parasite clearance in the population. CONCLUSION In monitoring drug resistance to SP, concurrent studies on possible confounding factors pertaining to development of resistance in falciparum malaria should be considered. The SP resistance potential detected in this study, cautions on its useful therapeutic life as an interim first-line drug against malaria in Tanzania and other malaria-endemic countries.
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Affiliation(s)
- Erasto V Mbugi
- Department of Veterinary Physiology, Biochemistry, Pharmacology and Toxicology, Faculty of Veterinary Medicine, Sokoine University of Agriculture (SUA), P.O. Box 3017, Morogoro, Tanzania
- Department of Biochemistry, School of Medicine, Muhimbili University College of Health Sciences (MUCHS), P.O. Box 65001, Dar es Salaam, Tanzania
- Cell Biology and immunology group, Department of Animal Sciences, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands
| | - Benezeth M Mutayoba
- Department of Veterinary Physiology, Biochemistry, Pharmacology and Toxicology, Faculty of Veterinary Medicine, Sokoine University of Agriculture (SUA), P.O. Box 3017, Morogoro, Tanzania
| | - Allen L Malisa
- Department of Biological Sciences, Faculty of Science, Sokoine University of Agriculture, P.O. Box 3038, Morogoro, Tanzania
| | - Sakurani T Balthazary
- Department of Veterinary Physiology, Biochemistry, Pharmacology and Toxicology, Faculty of Veterinary Medicine, Sokoine University of Agriculture (SUA), P.O. Box 3017, Morogoro, Tanzania
| | - Thomas B Nyambo
- Department of Biochemistry, School of Medicine, Muhimbili University College of Health Sciences (MUCHS), P.O. Box 65001, Dar es Salaam, Tanzania
| | - Hassan Mshinda
- Ifakara Health Research and Development Centre (IHRDC), Off Mlabani Road, P.O. Box 53, Ifakara, Kilombero District, Morogoro, Tanzania
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Zhou Z, Poe AC, Limor J, Grady KK, Goldman I, McCollum AM, Escalante AA, Barnwell JW, Udhayakumar V. Pyrosequencing, a high-throughput method for detecting single nucleotide polymorphisms in the dihydrofolate reductase and dihydropteroate synthetase genes of Plasmodium falciparum. J Clin Microbiol 2006; 44:3900-10. [PMID: 16957045 PMCID: PMC1698350 DOI: 10.1128/jcm.01209-06] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A pyrosequencing protocol was developed as a rapid and reliable method to identify the mutations of the dhfr and dhps genes of Plasmodium falciparum that are associated with antifolate resistance. The accuracy and specificity of this method were tested using six laboratory-cultured P. falciparum isolates harboring known single nucleotide polymorphisms (SNPs) in the genes dhfr (codons 50, 51, 59, 108, and 164) and dhps (codons 436, 437, 540, 581, and 613). The lowest threshold for detection of all the SNPs tested by pyrosequencing was the equivalent of two to four parasite genomes. Also, this method was highly specific for P. falciparum, as it did not amplify any DNA products from the other species of human malaria parasites. We also mixed wild-type and mutant-type parasite DNAs in various proportions to determine how pyrosequencing, restriction fragment length polymorphism (RFLP), and direct conventional sequencing (for dhfr) compared with each other in detecting different SNPs in the mixture. In general, pyrosequencing and RFLP showed comparable sensitivities in detecting most of the SNPs in dhfr except for the 164L mutation, which required at least twice the amount of DNA for pyroseqencing as for RFLP. For detecting SNPs in dhps, pyrosequencing was slightly more sensitive than RFLP and direct sequencing. Overall, pyrosequencing was faster and less expensive than either RFLP or direct sequencing. Thus, pyrosequencing is a practical alternative method that can be used in a high-throughput format for molecular surveillance of antimalarial-drug resistance.
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Affiliation(s)
- Zhiyong Zhou
- Division of Parasitic Diseases, National Center for Zoonotic, Vector-borne and Enteric Diseases, Coordinating Center for Infectious Diseases, Centers for Disease Control and Prevention, Chamblee, Georgia 30341, USA
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Nsimba B, Jafari-Guemouri S, Malonga DA, Mouata AM, Kiori J, Louya F, Yocka D, Malanda M, Durand R, Le Bras J. Epidemiology of drug-resistant malaria in Republic of Congo: using molecular evidence for monitoring antimalarial drug resistance combined with assessment of antimalarial drug use. Trop Med Int Health 2005; 10:1030-7. [PMID: 16185238 DOI: 10.1111/j.1365-3156.2005.01490.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In Congo, urgent efforts are needed to help with the revision of the national antimalarial drug policy. Despite its high resistance level, chloroquine (CQ) is still extensively used as the first-line treatment for uncomplicated Plasmodium falciparum malaria. The study was conducted in children under 5 years with uncomplicated malaria in Pointe-Noire and Brazzaville, the two largest cities that contain approximately 60% of the population of Congo. We investigated by polymerized chain reaction and sequencing methods the frequency distribution of molecular markers for antimalarial drug resistance, including mutations in P. falciparum chloroquine resistance transporter (pfcrt) gene associated with CQ resistance and mutations in dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes conferring resistance to sulphadoxine/pyrimethamine (SP) among pre-treatment P. falciparum isolates, as well as assessing antimalarial drug use in the community. pfcrt (K76T) mutation was present in most isolates (96.4%, n = 138) and high frequency (69.2%, n = 133) of triple-mutant dhfr-S108N, N51I, C59R was observed. The quintuple mutant (dhfr-S108N, N51I, C59R and dhps-A437G or S436A, K540E) considered as molecular marker for SP treatment failure was not found because dhps-K540E mutation was absent in isolates tested; this is a clear evidence for the excellent efficacy of SP that we previously described in the same population. The complete absence of the dhps-K540E mutation is a deterrent component for using this molecular marker as an early warning tool for SP resistance testing in that population. Poor compliance issues related to the antimalarial drug use including inappropriate manufacturing practices reported in this study require intensive attention and should be taken into account when implementing drug policy change. If Congo changes its treatment policy from CQ to SP monotherapy, this will not last long. The strategy of combining SP with other affordable and effective antimalarial drugs such as the artemisinin derivatives to improve efficacy and to delay the development of parasite resistance is essential.
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Affiliation(s)
- Basile Nsimba
- National Malaria Control Programme, Division for Disease Control, Ministry of Health, Brazzaville, Congo.
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Mockenhaupt FP, Teun Bousema J, Eggelte TA, Schreiber J, Ehrhardt S, Wassilew N, Otchwemah RN, Sauerwein RW, Bienzle U. Plasmodium falciparum dhfr but not dhps mutations associated with sulphadoxine-pyrimethamine treatment failure and gametocyte carriage in northern Ghana. Trop Med Int Health 2005; 10:901-8. [PMID: 16135198 DOI: 10.1111/j.1365-3156.2005.01471.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Both use of sulphadoxine-pyrimethamine (SP) and SP-resistance of Plasmodium falciparum are increasing in sub-Saharan Africa. Mutations in the P. falciparum dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes can predict treatment failure of SP, however, the degree of this relationship varies regionally. In northern Ghana, pre-treatment dhfr/dhps genotypes were examined in 126 children and associations with PCR-corrected SP treatment outcome and gametocyte carriage were analysed. SP treatment failure within 4 weeks of follow-up occurred in 28%. Among all pre-treatment isolates, the dhfr triple mutation (Ile-51 + Arg-59 + Asn-108) was detected in 47%. Compared with dhfr wildtype parasites, the presence of the dhfr triple mutation increased the risk of treatment failure tenfold. Likewise, parasite clearance was delayed in the presence of dhfr variants. Dhfr mutants and dhps Gly-437 were selected in treatment failure isolates. Gametocytaemia 1 week following treatment was strongly associated with dhfr mutations. Remarkably, this was also true for the prevalence of gametocytes at recruitment. Dhps alleles did neither influence treatment outcome nor gametocyte carriage. In northern Ghana, the prevalence of the dhfr triple mutation can be used as a tool to screen for and to monitor SP resistance. The lack of association between dhps alleles and SP treatment outcome suggests a minor role of these molecular markers in this region at present.
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Affiliation(s)
- Frank P Mockenhaupt
- Institute of Tropical Medicine, Charité-University Medicine Berlin, Berlin, Germany.
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Happi CT, Gbotosho GO, Folarin OA, Akinboye DO, Yusuf BO, Ebong OO, Sowunmi A, Kyle DE, Milhous W, Wirth DF, Oduola AMJ. Polymorphisms in Plasmodium falciparum dhfr and dhps genes and age related in vivo sulfadoxine-pyrimethamine resistance in malaria-infected patients from Nigeria. Acta Trop 2005; 95:183-93. [PMID: 16023986 DOI: 10.1016/j.actatropica.2005.06.015] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Revised: 06/04/2005] [Accepted: 06/06/2005] [Indexed: 11/26/2022]
Abstract
Mutations in Plasmodium falciparum dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes have been used as means to predict treatment failure to sulfadoxine-pyrimethamine (SP) and for monitoring/surveillance of resistance to the drug in many areas where malaria is endemic. However, patients responses to treatment are significantly dependent on factors like host immunity profile of treated patients. In order to investigate the relationship between molecular markers of SP resistance, host immunity and clinical outcome, the association between pre-treatment dhfr and dhps genotypes, age and treatment outcomes was evaluated in 109 children treated with SP for acute uncomplicated malaria in Ibadan, Nigeria. Seventy-three percent of the children were cured with the drug, while 27% failed treatment after 28 days of follow-up. All children infected with parasites harboring less than two dhfr/dhps mutations were cured with SP. The dhfr triple (Asn-108/Ile-51/Arg-59) mutants or the dhps double mutants (Gly-437/Glu-540) were independently associated with SP treatment failure in children aged less than 5 years, but not in older children. The dhfr and dhps quintuple mutant (dhfr triple mutant+dhps double mutant) was the genotype most strongly associated with SP treatment failure (OR=24.72, 95%CI=8.24-74.15) in both younger and older children.
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Affiliation(s)
- C T Happi
- Malaria Research Laboratories, Postgraduate Institute for Medical Research and Training (PIMRAT), College of Medicine, University of Ibadan, Ibadan, Nigeria.
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Berzosa PJ, Puente S, Benito A. Malaria cure with sulphadoxine/pyrimethamine combination in 12 semi-immune adults from West-Central Africa with high rates of point mutations in Plasmodium falciparum dhfr and dhps genes. Parasitol Res 2005; 97:287-9. [PMID: 16012864 DOI: 10.1007/s00436-005-1424-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Accepted: 05/18/2005] [Indexed: 10/25/2022]
Abstract
We report 12 uncomplicated falciparum-malaria cases from semi-immune people from Central Africa treated with sulfadoxine/pyrimethamine (Fansidar) in a Spanish hospital. We resolved by PCR-RFLP the mutations in dhfr and dhps genes related to resistance to antifolate drugs. The 12 patients presented high frequencies of combined mutations in both genes but they were completely cured after treatment.
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Affiliation(s)
- Pedro J Berzosa
- Laboratorio de Malaria, Servicio de Parasitología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Ctra. Majadahonda-Pozuelo Km 2, 28220 Majadahonda, Madrid, Spain.
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Gatton ML, Martin LB, Cheng Q. Evolution of resistance to sulfadoxine-pyrimethamine in Plasmodium falciparum. Antimicrob Agents Chemother 2004; 48:2116-23. [PMID: 15155209 PMCID: PMC415611 DOI: 10.1128/aac.48.6.2116-2123.2004] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The development of resistance to sulfadoxine-pyrimethamine by Plasmodium parasites is a major problem for the effective treatment of malaria, especially P. falciparum malaria. Although the molecular basis for parasite resistance is known, the factors promoting the development and transmission of these resistant parasites are less clear. This paper reports the results of a quantitative comparison of factors previously hypothesized as important for the development of drug resistance, drug dosage, time of treatment, and drug elimination half-life, with an in-host dynamics model of P. falciparum malaria in a malaria-naïve host. The results indicate that the development of drug resistance can be categorized into three stages. The first is the selection of existing parasites with genetic mutations in the dihydrofolate reductase or dihydropteroate synthetase gene. This selection is driven by the long half-life of the sulfadoxine-pyrimethamine combination. The second stage involves the selection of parasites with allelic types of higher resistance within the host during an infection. The timing of treatment relative to initiation of a specific anti-P. falciparum EMP1 immune response is an important factor during this stage, as is the treatment dosage. During the third stage, clinical treatment failure becomes prevalent as the parasites develop sufficient resistance mutations to survive therapeutic doses of the drug combination. Therefore, the model output reaffirms the importance of correct treatment of confirmed malaria cases in slowing the development of parasite resistance to sulfadoxine-pyrimethamine.
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Affiliation(s)
- Michelle L Gatton
- Malaria and Scabies Group, Queensland Institute of Medical Research, PO Royal Brisbane Hospital, Queensland 4029, Australia.
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Cox-Singh J, Lu HY, Davis TME, Ilett KF, Hackett LP, Matusop A, Singh B. Application of a multi-faceted approach for the assessment of treatment response in falciparum malaria: a study from Malaysian Borneo. Int J Parasitol 2004; 33:1545-52. [PMID: 14572517 DOI: 10.1016/s0020-7519(03)00199-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Thirty-two patients reporting to the Lundu District Hospital, Sarawak, Malaysian Borneo, with uncomplicated falciparum malaria were recruited into a multifaceted study to assess treatment response. Following combined chloroquine and sulphadoxine/pyrimethamine treatment the patients were followed for 28 days according to the World Health Organisation in vivo drug response protocol. The in vivo study revealed that 13 (41%) of the patients had a sensitive response to treatment, five (16%) cleared asexual stage parasites but had persistent gametocytes, 11 (34%) had RI type resistance and three (9%) had RII type resistance requiring quinine intervention before day 7 for parasite clearance. Although clinically insignificant, patients with persistent gametocytes, surviving chloroquine and sulphadoxine/pyrimethamine treatment during maturation, were placed in the reduced response to treatment group for analysis. Allelic typing detected 100% prevalence of the pfcrt K76T marker associated with chloroquine resistance and 78% prevalence of the pfdhfr NRNL haplotype associated with sulphadoxine/pyrimethamine treatment failure. High serum chloroquine levels and pfdhfr haplotypes with <or=2 point mutations were independently associated with a sensitive response to treatment. However four patients in the sensitive response group had both low serum chloroquine levels and the pfdhfr NRNL haplotype. A degree of immunity, consistent with malaria endemicity, may account for the apparently paradoxical presence of markers of drug resistance in the sensitive group.
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Affiliation(s)
- J Cox-Singh
- Faculty of Medicine and Health Sciences, University Malaysia Sarawak, 93150, Sarawak, Malaysian Borneo, Kuching, Malaysia.
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Kofoed PE, Alfrangis M, Poulsen A, Rodrigues A, Gjedde SB, Rønn A, Rombo L. Genetic markers of resistance to pyrimethamine and sulfonamides in Plasmodium falciparum parasites compared with the resistance patterns in isolates of Escherichia coli from the same children in Guinea-Bissau. Trop Med Int Health 2004; 9:171-7. [PMID: 14728622 DOI: 10.1046/j.1365-3156.2003.01164.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The antifolate drugs sulphadoxine and pyrimethamine are used for treatment of chloroquine-resistant Plasmodium falciparum in Africa. Resistance to pyrimethamine has been associated with point mutations in the dhfr-gene and resistance to sulphadoxine with mutations in the dhps-gene. There is concern that the use of the antifolates trimethoprim and sulphamethoxazole for treatment of other infectious diseases will result in the selection of malaria parasites with mutations in these genes. In Guinea-Bissau, where sulfonamide and trimethoprim-containing drugs have been used extensively, we decided to assess the prevalence of mutations in the dhfr-and dhps-gene in P. falciparum isolated from children suffering from acute malaria and to assess the resistance patterns to trimethoprim/sulphamethoxazole in Escherichia coli isolated from the same patients. A thick film and a blood sample for polymerase chain reaction (PCR) were obtained from 100 children attending the Bandim Health Centre in Bissau with symptoms compatible with malaria. Furthermore, a stool sample was collected from the same children and cultured for E. coli. Of the cultured E. coli, 67% were resistant both to sulfonamides and trimethoprim, 4% to sulfonamides alone, 3% to trimethoprim alone while 26% were fully sensitive to both drugs. PCR was successfully performed in 97 blood samples. Of these, 41% had triple mutations at the dhfr-gene (at codons 51, 59 and 108), and 15% had triple mutations plus mutation at codon 437 in the dhps-gene. Only 45% harboured the wild-type dhfr-gene. Thus both bacterial resistance and mutations in the parasitic genes were common, but not linked in the individual child. As sulphadoxine-pyrimethamine has only been used as a second line treatment for chloroquine resistant malaria in Guinea-Bissau for a few years, it is worrying to find a high prevalence of mutations in the parasitic genes coding for resistance to these drugs. Therefore, restricting the use of sulphadoxine-pyrimethamine for the treatment of chloroquine resistant malaria might not be sufficient to prevent the development of resistance in the parasites as long as antifolate drugs are used extensively.
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Berens N, Schwoebel B, Jordan S, Vanisaveth V, Phetsouvanh R, Christophel EM, Phompida S, Jelinek T. Plasmodium falciparum: correlation of in vivo resistance to chloroquine and antifolates with genetic polymorphisms in isolates from the south of Lao PDR. Trop Med Int Health 2003; 8:775-82. [PMID: 12950663 DOI: 10.1046/j.1365-3156.2003.01099.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Levels of drug resistance of Plasmodium falciparum strains against antimalarials have increased in Laos. In several studies, chloroquine (CQ) resistance has been associated with point mutations in the Pfcrt and pfmdr genes, and sulphadoxine/pyrimethamine (S/P) resistance with point mutations in the genes of dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS). We combined a study of these molecular markers with an in vivo antimalarial drug sensitivity study in Attapeu province in the south of Lao PDR. We treated 100 patients with either CQ, S/P or a combination of both. In the CQ group, Pfcrt mutations showed a very high sensitivity (100%) but a low specificity (12.5%) to predict resistance. The combination of mutations in the Pfcrt and pfmdr genes was highly specific and had a positive predictive value of 100%. Mutations in the DHPS gene showed a high correlation with the development of resistance. The prevalence of mutations in the DHFR gene, especially codon 108 Asn, was predictive with high sensitivity (100%) but low specificity. Isolates derived from patients treated with a combination of both drugs showed a high correlation between the mutation in codon 437 of DHPS gene and in vivo-resistance (odds ratio 16.00, CI). The study provides evidence for the existence of antimalarial drug resistance in the south of Lao PDR, and offers a molecular method to predict resistance.
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Affiliation(s)
- Nicole Berens
- Department of Infectious Diseases and Tropical Medicine, University of Munich, Munich, Germany.
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Pearce RJ, Drakeley C, Chandramohan D, Mosha F, Roper C. Molecular determination of point mutation haplotypes in the dihydrofolate reductase and dihydropteroate synthase of Plasmodium falciparum in three districts of northern Tanzania. Antimicrob Agents Chemother 2003; 47:1347-54. [PMID: 12654669 PMCID: PMC152520 DOI: 10.1128/aac.47.4.1347-1354.2003] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The antimalarial combination of sulfadoxine and pyrimethamine (SP) was introduced as first-line treatment for uncomplicated malaria in Tanzania during 2001 following 18 years of second-line use. The genetic determinants of in vitro resistance to the two drugs individually are shown to be point mutations at seven sites in the dihydrofolate reductase gene (dhfr) conferring resistance to pyrimethamine and five sites in the dihydropteroate synthase (dhps) gene conferring resistance to sulfadoxine. Different combinations of mutations within each gene confer differing degrees of insensitivity, but information about the frequency with which allelic haplotypes occur has been lacking because of the complicating effects of multiple infection. Here we used a novel high-throughput sequence-specific oligonucleotide probe-based approach to examine the present resistance status of three Plasmodium falciparum populations in northern Tanzania. By using surveys of asymptomatic infections and screening for the presence of all known point mutations in dhfr and dhps genes, we showed that just five dhfr and three dhps allelic haplotypes are present. High frequencies of both triple-mutant dhfr and double-mutant dhps mutant alleles were found in addition to significant interregional heterogeneity in allele frequency. In vivo studies have shown that the cooccurrence of three dhfr mutations and two dhps mutations in an infection prior to treatment is statistically predictive of treatment failure. We have combined data for both loci to determine the frequency of two-locus genotypes. The triple-dhfr/double-dhps genotype is present in all three regions with frequencies ranging between 30 and 63%, indicating that treatment failure rates are likely to be high.
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Affiliation(s)
- Richard J Pearce
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom.
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Jafari S, Le Bras J, Asmar M, Durand R. Molecular survey of Plasmodium falciparum resistance in south-eastern Iran. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2003; 97:119-24. [PMID: 12803866 DOI: 10.1179/000349803235001552] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In south-eastern Iran, the sulfadoxine-pyrimethamine (SP) combination has been used to treat malaria caused by chloroquine-resistant Plasmodium falciparum. To explore the molecular basis of antimalarial resistance in this region, the dhfr, dhps and pfcrt genes of 50 clinical isolates of P. falciparum, collected from cases of uncomplicated malaria in 2000-2001, were checked for the point mutations that appear associated with SP or chloroquine (CQ) resistance. The results of the study, which was based on a PCR followed by DNA sequencing, indicated that all 50 isolates presented the DHFR S108N mutation associated with pyrimethamine resistance. Seven isolates (14%) had a triple DHFR mutation (S108N, N51I, C59R) and 32 (64%) had a double mutation in this domain. Thirty-nine isolates (78%) had the wild-type DHFR 51 codon but only 15 (30%) had the wild-type DHFR 59 codon. Eleven isolates (22%) only had the DHFR S108N mutation. All isolates had the wild-type DHPS 436 and 540 codons and all but two of the isolates had the wild-type DHPS 437 codon. All isolates but one had the PFCRT K76T mutation associated with CQ treatment failure. The results of this preliminary investigation indicate that SP may remain the treatment of choice for cases of uncomplicated malaria in south-eastern Iran.
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Affiliation(s)
- S Jafari
- Laboratoire de Parasitologie, Hôpital Bichat-Claude Bernard, Assistance Publique-Hôpitaux de Paris, 46 rue Henri Huchard, 75877 Paris Cedex 18, France
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Labbé AC, Patel S, Crandall I, Kain KC. A molecular surveillance system for global patterns of drug resistance in imported malaria. Emerg Infect Dis 2003; 9:33-6. [PMID: 12533279 PMCID: PMC2873765 DOI: 10.3201/eid0901.020121] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Analysis of imported malaria in travelers may represent a novel surveillance system for drug-resistant malaria. We analyzed consecutive falciparum malaria isolates from Canadian travelers from 1994 to 2000, for polymorphisms in pfcrt, dhfr, and dhps linked to chloroquine and pyrimethamine/sulfadoxine resistance. Forty percent of isolates possessed the K76 pfcrt allele, suggesting that many imported falciparum infections are still responsive to chloroquine. Travelers who had recently taken chloroquine had a significantly increased risk of harboring isolates with pfcrt resistance alleles (odds ratio = 4.47; p=0.03). The presence of two or more mutations in dhfr or dhps was found in 64.8% (95% confidence interval [CI] 54.6 to 73.9) and in 30.4% (95% CI 21.7 to 40.3) of isolates, respectively, and increased significantly over the course of the study. These molecular markers indicate that pyrimethamine/sulfadoxine resistance is increasing and is now too high to rely on this drug as a routine therapeutic agent to treat malaria in travelers.
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Affiliation(s)
| | - Samir Patel
- Toronto General Hospital, University of Toronto, Canada
| | - Ian Crandall
- Toronto General Hospital, University of Toronto, Canada
| | - Kevin C. Kain
- Toronto General Hospital, University of Toronto, Canada
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Checchi F, Durand R, Balkan S, Vonhm BT, Kollie JZ, Biberson P, Baron E, Le Bras J, Guthmann JP. High Plasmodium falciparum resistance to chloroquine and sulfadoxine-pyrimethamine in Harper, Liberia: results in vivo and analysis of point mutations. Trans R Soc Trop Med Hyg 2002; 96:664-9. [PMID: 12625147 DOI: 10.1016/s0035-9203(02)90346-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
In Liberia, little information is available on the efficacy of antimalarials against Plasmodium falciparum malaria. We measured parasitological resistance to chloroquine and sulfadoxine-pyrimethamine (SP) in Harper, south-west Liberia in a 28-d study in vivo. A total of 50 patients completed follow-up in the chloroquine group, and 66 in the SP group. The chloroquine failure rate was 74.0% (95% confidence interval [95% CI] 59.7-85.4%) after 14 d of follow-up and 84.0% (95% CI 70.9-92.8%) after 28 d (no polymerase chain reaction [PCR] analysis was performed to detect reinfections in this group). In the SP group, the failure rate was 48.5% (95% CI 36.2-61.0%) after 14 d and 69.7% (95% CI 57.1-80.4%) after 28 d, readjusted to 51.5% (95% CI 38.9-64.0%) after taking into account reinfections detected by PCR. Genomic analysis of parasite isolates was also performed to look for point mutations associated with resistance. Genotyping of parasite isolates revealed that all carried chloroquine-resistant K-76T mutations at gene pfcrt, whereas the triple mutation (S108N, N511, C59R) at dhfr and the A437G mutation at dhps, both associated with resistance to SP, were present in 84% and 79% of pretreatment isolates respectively. These results seriously question the continued use of chloroquine and SP in Harper and highlight the urgency of making alternative antimalarial therapies available. Our study confirms that resistance to chloroquine may be high in Liberia and yields hitherto missing information on SP.
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Affiliation(s)
- F Checchi
- Laboratoire de Parasitologie-Mycologie, Hôpital Bichat-Claude Bernard, 46 rue Henri Huchard, 75877 Paris, France
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Nair S, Brockman A, Paiphun L, Nosten F, Anderson TJC. Rapid genotyping of loci involved in antifolate drug resistance in Plasmodium falciparum by primer extension. Int J Parasitol 2002; 32:852-8. [PMID: 12062556 DOI: 10.1016/s0020-7519(02)00033-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Current methods used to genotype point mutations in Plasmodium falciparum genes involved in resistance to antifolate drugs include restriction digestion of PCR products, allele-specific amplification or sequencing. Here we demonstrate that known point mutations in dihydrofolate reductase and dihydropteroate synthase can be scored quickly and accurately by single-nucleotide primer extension and detection of florescent products on a capillary sequencer. We use this method to genotype parasites in natural infections from the Thai-Myanmar border. This approach could greatly simplify large-scale screening of resistance mutations of the type required for evaluating and updating antimalarial drug treatment policies. The method can be easily adapted to other P. falciparum genes and will greatly simplify scoring of point mutations in this and other parasitic organisms.
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Affiliation(s)
- Shalini Nair
- Southwest Foundation for Biomedical Research (SFBR), PO Box 760549, San, Antonio, TX 78245, USA.
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Eskandarian AA, Keshavarz H, Basco LK, Mahboudi F. Do mutations in Plasmodium falciparum dihydropteroate synthase and dihydrofolate reductase confer resistance to sulfadoxine-pyrimethamine in Iran? Trans R Soc Trop Med Hyg 2002; 96:96-8. [PMID: 11926005 DOI: 10.1016/s0035-9203(02)90254-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The key codons of dihydropteroate synthase (dhps) and dihydrofolate reductase (dhfr) genes implicated in sulfadoxine-pyrimethamine (SP) resistance were determined by allele-specific polymerase chain reaction in Plasmodium falciparum isolates collected in 1999 from 35 Iranian patients treated with SP. Seven isolates had Glu-540 dhps allele but 5 of these isolates were characterized to possess wild-type dhfr alleles. Seven additional isolates were polyclonal with mixed Lys- and Glu-540. The key dhfr mutation associated with pyrimethamine resistance, Asn-108, was found in 4 isolates. In one patient the presence of Lys- and Glu-540 in dhps and Asn-108 and Arg-59 in dhfr was associated with treatment failure. However, more studies are needed to determine whether clinical response to SP and mutations in these genes are correlated in Iran.
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Affiliation(s)
- Abbas-Ali Eskandarian
- Department of Medical Parasitology and Mycology, School of Health, Institute for Health Researches, University of Medical Sciences of Tehran, Tehran, Iran
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Abstract
Drug resistance is complicating the treatment of parasitic diseases. We review here the basic mechanisms of parasite resistance in malaria, sleeping sickness, leishmaniasis and common helminthiases. Parasites resort to multiple biochemical means to achieve resistance and we have begun to isolate and characterize the genes/proteins implicated in resistance. Understanding drug resistance is essential for the control of parasitic diseases.
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Affiliation(s)
- M Ouellette
- Centre de Recherche en Infectiologie du Centre de Recherche du CHUL and Département de Microbiologie, Faculté de Médecine, Université Laval, Québec, Canada.
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Mutabingwa T, Nzila A, Mberu E, Nduati E, Winstanley P, Hills E, Watkins W. Chlorproguanil-dapsone for treatment of drug-resistant falciparum malaria in Tanzania. Lancet 2001; 358:1218-23. [PMID: 11675058 DOI: 10.1016/s0140-6736(01)06344-9] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Resistance to the affordable malaria treatments chloroquine and pyrimethamine-sulfadoxine is seriously impeding malaria control through treatment in east Africa. We did an open, alternate drug allocation study to assess the efficacy of chlorproguanil-dapsone in the treatment of falciparum malaria clinically resistant to pyrimethamine-sulfadoxine. METHODS Children younger than 5 years with non-severe falciparum malaria, attending Muheza district hospital in Tanzania, were treated with the standard regimen of pyrimethamine-sulfadoxine. Patients whose clinical symptoms resolved but who remained parasitaemic 7 days after pyrimethamine-sulfadoxine were followed up for 1 month. Clinical malaria episodes were retreated with either single dose pyrimethamine-sulfadoxine or a 3-day regimen of chlorproguanil-dapsone. Those with parasitaemia after 7 days were treated with chlorproguanil-dapsone. Parasite DNA was collected on day 7 after first treatment with pyrimethamine-sulfadoxine and we looked for point mutations in the genes encoding dihydrofolate reductase (dhfr) and dyhydropteroate synthetase (dhps). FINDINGS 360 children were enrolled and treated with pyrimethamine-sulfadoxine. On day 7, 192 (55%) of 348 had cleared parasitaemia. Of the remaining 156 parasitaemic children, 140 (90%) were followed up to day 28, and 92 (66%) of 140 developed clinical malaria. These 92 patients were alternately retreated with either pyrimethamine-sulfadoxine (46) or chlorproguanil-dapsone (46). 28 (61%) of 46 children retreated with pyrimethamine-sulfadoxine were still parasitaemic at day 7, compared with three (7%) of 44 [corrected] children retreated with chlorproguanil-dapsone. Resistance to pyrimethamine-sulfadoxine increased from 45% (156/348) at the first treatment to 61% (28/46) after retreatment. 83 of 85 parasite isolates collected after the first pyrimethamine-sulfadoxine treatment, and before and after the second treatments with pyrimethamine-sulfadoxine and chlorproguanil-dapsone showed triple-mutant dhfr alleles, associated with a variety of dhps mutations. INTERPRETATION Most patients treated with pyrimethamine-sulfadoxine, who remain parasitaemic at day 7, develop new malaria symptoms within 1 month. Chlorproguanil-dapsone was a practicable therapy under these circumstances. Analysis of parasite dhfr and dhps before and after treatment supports the view that pyrimethamine-sulfadoxine resistance in this part of Africa is primarily due to parasites with three mutations in the dhfr domain.
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Affiliation(s)
- T Mutabingwa
- National Institute for Medical Research, Amani-Tanga, Tanzania.
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Hughes AL, Verra F. Very large long-term effective population size in the virulent human malaria parasite Plasmodium falciparum. Proc Biol Sci 2001; 268:1855-60. [PMID: 11522206 PMCID: PMC1088819 DOI: 10.1098/rspb.2001.1759] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
It has been proposed that the virulent human malaria parasite Plasmodium falciparum underwent a recent severe population bottleneck. In order to test this hypothesis, we estimated the effective population size of this species from the patterns of nucleotide substitution at 23 nuclear protein-coding loci, using a variety of methods based on coalescent theory. Both simple methods and phylogenetically based maximum-likelihood methods yielded the conclusion that the effective population size of this species has been of the order of at least 10(5) for the past 300,000-400,000 years.
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Affiliation(s)
- A L Hughes
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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