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Maiga H, Grivoyannis A, Sagara I, Traore K, Traore OB, Tolo Y, Traore A, Bamadio A, Traore ZI, Sanogo K, Doumbo OK, Plowe CV, Djimde AA. Selection of pfcrt K76 and pfmdr1 N86 Coding Alleles after Uncomplicated Malaria Treatment by Artemether-Lumefantrine in Mali. Int J Mol Sci 2021; 22:ijms22116057. [PMID: 34205228 PMCID: PMC8200001 DOI: 10.3390/ijms22116057] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 11/18/2022] Open
Abstract
Background: Artemether-lumefantrine is a highly effective artemisinin-based combination therapy that was adopted in Mali as first-line treatment for uncomplicated Plasmodium falciparum malaria. This study was designed to measure the efficacy of artemether-lumefantrine and to assess the selection of the P. falciparum chloroquine resistance transporter (pfcrt) and P. falciparum multi-drug resistance 1 (pfmdr1) genotypes that have been associated with drug resistance. Methods: A 28-day follow-up efficacy trial of artemether-lumefantrine was conducted in patients aged 6 months and older suffering from uncomplicated falciparum malaria in four different Malian areas during the 2009 malaria transmission season. The polymorphic genetic markers MSP2, MSP1, and Ca1 were used to distinguish between recrudescence and reinfection. Reinfection and recrudescence were then grouped as recurrent infections and analyzed together by PCR-restriction fragment length polymorphism (RFLP) to identify candidate markers for artemether-lumefantrine tolerance in the P. falciparum chloroquine resistance transporter (pfcrt) gene and the P. falciparum multi-drug resistance 1 (pfmdr1) gene. Results: Clinical outcomes in 326 patients (96.7%) were analyzed and the 28-day uncorrected adequate clinical and parasitological response (ACPR) rate was 73.9%. The total PCR-corrected 28-day ACPR was 97.2%. The pfcrt 76T and pfmdr1 86Y population prevalence decreased from 49.3% and 11.0% at baseline (n = 337) to 38.8% and 0% in patients with recurrent infection (n = 85); p = 0.001), respectively. Conclusion: Parasite populations exposed to artemether-lumefantrine in this study were selected toward chloroquine-sensitivity and showed a promising trend that may warrant future targeted reintroduction of chloroquine or/and amodiaquine.
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Affiliation(s)
- Hamma Maiga
- Institut National de Sante Publique, INSP, Bamako P.O. Box 1771, Mali;
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | | | - Issaka Sagara
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Karim Traore
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Oumar B. Traore
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Youssouf Tolo
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Aliou Traore
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Amadou Bamadio
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Zoumana I. Traore
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Kassim Sanogo
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | - Ogobara K. Doumbo
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
| | | | - Abdoulaye A. Djimde
- Malaria Research & Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Bamako P.O. Box 1805, Mali; (I.S.); (K.T.); (O.B.T.); (Y.T.); (A.T.); (A.B.); (Z.I.T.); (K.S.); (O.K.D.)
- Correspondence: ; Tel.: +223-2022-8109
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Cisse M, Awandare GA, Soulama A, Tinto H, Hayette MP, Guiguemdé RT. Recent uptake of intermittent preventive treatment during pregnancy with sulfadoxine-pyrimethamine is associated with increased prevalence of Pfdhfr mutations in Bobo-Dioulasso, Burkina Faso. Malar J 2017; 16:38. [PMID: 28114990 PMCID: PMC5259838 DOI: 10.1186/s12936-017-1695-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/13/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The impact of sulfadoxine-pyrimethamine (SP) used as intermittent preventive treatment during pregnancy (IPTp-SP) on mutant parasite selection has been poorly documented in Burkina Faso. This study sought first to explore the relationship between IPTp-SP and the presence of mutant parasites. Second, to assess the relationship between the mutant parasites and adverse pregnancy outcomes. METHODS From September to December 2010, dried blood spots (DBS) were collected during antenatal care visits and at delivery from 109 pregnant women with microscopically confirmed falciparum malaria infection. DBS were analysed by PCR-restriction fragment length polymorphism (PCR-RFLP) for the polymorphisms at codons 51, 59, 108, and 164 of the Pfdhfr gene and codons 437 and 540 in the Pfdhps gene. RESULTS Both the Pfdhfr and Pfdhps genes were successfully genotyped in 92.7% (101/109) of the samples. The prevalence of Pfdhfr mutations N51I, C59R and S108N was 71.3, 42.6 and 64.4%, respectively. Overall, 80.2% (81/101) of samples carried the Pfdhps A437G mutation. None of the samples had the Pfdhfr I164L and the Pfdhps K540E mutations. The prevalence of the triple mutation N51I + C59R + S108N was 25.7% (26/101). The use of IPTp-SP was associated with a threefold increased odds of Pfdhfr C59R mutation [crude OR 3.29; 95% CI (1.44-7.50)]. Pregnant women with recent uptake of IPTp-SP were at higher odds of both the Pfdhfr C59R mutation [adjusted OR 4.26; 95% CI (1.64-11.07)] and the Pfdhfr intermediate-to-high resistance, i.e., ≥ 2 Pfdhfr mutations [adjusted OR 3.45; 95% CI (1.18-10.07)]. There was no statistically significant association between the presence of the Pfdhfr intermediate-to-high resistance and parasite densities or both maternal haemoglobin level and anaemia. CONCLUSION The data indicate that despite the possibility that IPTp-SP contributes to the selection of resistant parasites, it did not potentiate pregnancy-associated malaria morbidity, suggesting the continuation of SP use as IPTp in Burkina Faso.
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Affiliation(s)
- Mamoudou Cisse
- Laboratory of Parasitology and Entomology, Centre MURAZ, 01 BP 390, Bobo-Dioulasso, Burkina Faso
| | - Gordon A. Awandare
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Alamissa Soulama
- Laboratory of Parasitology and Entomology, Centre MURAZ, 01 BP 390, Bobo-Dioulasso, Burkina Faso
| | - Halidou Tinto
- Department of Clinical Research, Centre MURAZ, Bobo-Dioulasso, Burkina Faso
| | - Marie-Pierre Hayette
- Laboratory of Clinical Microbiology, University Hospital of Liège, Liège, Belgium
| | - Robert T. Guiguemdé
- Laboratory of Parasitology and Entomology, Centre MURAZ, 01 BP 390, Bobo-Dioulasso, Burkina Faso
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Maiga H, Lasry E, Diarra M, Sagara I, Bamadio A, Traore A, Coumare S, Bahonan S, Sangare B, Dicko Y, Diallo N, Tembely A, Traore D, Niangaly H, Dao F, Haidara A, Dicko A, Doumbo OK, Djimde AA. Seasonal Malaria Chemoprevention with Sulphadoxine-Pyrimethamine and Amodiaquine Selects Pfdhfr-dhps Quintuple Mutant Genotype in Mali. PLoS One 2016; 11:e0162718. [PMID: 27662368 PMCID: PMC5035027 DOI: 10.1371/journal.pone.0162718] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 08/26/2016] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Seasonal malaria chemoprevention (SMC) with sulphadoxine-pyrimethamine (SP) plus amodiaquine (AQ) is being scaled up in Sahelian countries of West Africa. However, the potential development of Plasmodium falciparum resistance to the respective component drugs is a major concern. METHODS Two cross-sectional surveys were conducted before (August 2012) and after (June 2014) a pilot implementation of SMC in Koutiala, Mali. Children aged 3-59 months received 7 rounds of curative doses of SP plus AQ over two malaria seasons. Genotypes of P. falciparum Pfdhfr codons 51, 59 and 108; Pfdhps codons 437 and 540, Pfcrt codon 76 and Pfmdr1codon 86 were analyzed by PCR on DNA from samples collected before and after SMC, and in non-SMC patient population as controls (November 2014). RESULTS In the SMC population 191/662 (28.9%) and 85/670 (12.7%) of children were P. falciparum positive by microscopy and were included in the molecular analysis before (2012) and after SMC implementation (2014), respectively. In the non-SMC patient population 220/310 (71%) were successfully PCR analyzed. In the SMC children, the prevalence of all molecular markers of SP resistance increased significantly after SMC including the Pfdhfr-dhps quintuple mutant genotype, which was 1.6% before but 7.1% after SMC (p = 0.02). The prevalence of Pfmdr1-86Y significantly decreased from 26.7% to 15.3% (p = 0.04) while no significant change was seen for Pfcrt 76T. In 2014, prevalence of all molecular markers of SP resistance were significantly higher among SMC children compared to the non-SMC population patient (p < 0.01). No Pfdhfr-164 mutation was found neither at baseline nor post SMC. CONCLUSION SMC increased the prevalence of molecular markers of P. falciparum resistance to SP in the treated children. However, there was no significant increase of these markers of resistance in the general parasite population after 2 years and 7 rounds of SMC.
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Affiliation(s)
- Hamma Maiga
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Estrella Lasry
- Médecins Sans Frontières (MSF), New York, New York, United States of America
| | - Modibo Diarra
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Issaka Sagara
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Amadou Bamadio
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Aliou Traore
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Samba Coumare
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | | | - Boubou Sangare
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Yeyia Dicko
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Nouhoum Diallo
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Aly Tembely
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Djibril Traore
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Hamidou Niangaly
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - François Dao
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Aboubecrine Haidara
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Alassane Dicko
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Ogobara K. Doumbo
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Abdoulaye A. Djimde
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odontostomatology and Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Mali
- * E-mail:
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Mutational analysis of Plasmodium falciparum dihydrofolate reductase and dihydropteroate synthase genes in the interior division of Sabah, Malaysia. Malar J 2013; 12:445. [PMID: 24321120 PMCID: PMC4029390 DOI: 10.1186/1475-2875-12-445] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 12/04/2013] [Indexed: 01/15/2023] Open
Abstract
Background The sulphadoxine/pyrimethamine (SDX/PYR) combination had been chosen to treat
uncomplicated falciparum malaria in Malaysia for more than 30 years.
Non-silent mutations in dihydrofolate reductase (dhfr) and
dihydropteroate synthase (dhps) genes are responsible for the
resistance to pyrimethamine and sulphadoxine, respectively. This
study reports the mutational analysis of pfdhfr and pfdhps
in single Plasmodium falciparum infection isolates from the
interior division of Sabah, Malaysian Borneo. Methods A total of 22 P. falciparum single infection isolates collected from
two districts of the interior division of Sabah from February to November
2010 were recruited for the mutational study of pfdhfr and
pfdhps. Both genes were amplified by nested PCR prior to DNA
sequencing and mutational analysis. Results A total of three pfdhfr and four pfdhps alleles were
identified. The most prevalent pfdhfr allele is ANRNL (86%)
involving triple mutation at position 108(S to N), 59(C to R) and 164(I to
L). In pfdhps, two novel alleles, SGTGA (73%) and AAKAA (5%) were
identified. Alleles involving triple mutation in both pfdhfr
(ANRNL) and pfdhps (SGTGA), which were absent in Sabah in a study
conducted about 15 years ago, are now prevalent. Conclusions High prevalence of mutations in SDX/PYR associated drug resistance genes are
reported in this study. This mutational study of pfdhps and
pfdhfr indicating that SDX/PYR should be discontinued in this
region.
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Ogouyèmi-Hounto A, Ndam NT, Kinde Gazard D, d'Almeida S, Koussihoude L, Ollo E, Azagnandji C, Bello M, Chippaux JP, Massougbodji A. Prevalence of the molecular marker of Plasmodium falciparum resistance to chloroquine and sulphadoxine/pyrimethamine in Benin seven years after the change of malaria treatment policy. Malar J 2013; 12:147. [PMID: 23634705 PMCID: PMC3651273 DOI: 10.1186/1475-2875-12-147] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 04/28/2013] [Indexed: 12/03/2022] Open
Abstract
Background In Benin, the National Malaria Control Programme (NMCP) changed the policy of malaria treatment in 2004 following increasing of failure rate of treatment with chloroquine (CQ) and sulphadoxine-pyrimethamine (SP). The objective of this study was to determinate the prevalence of Plasmodium falciparum molecular markers that are associated with resistance to CQ and SP in Benin seven years after the new policy was instituted. Methods The study was conducted in southern Benin, a region characterized by a perennial malaria transmission. Blood samples were collected in 2011 from children presenting with symptomatic and asymptomatic P. falciparum infections and living in the same area. The prevalence of critical point mutations in the genes of pfcrt (codon 76), pfmdr1 (codon 86), pfdhfr (codons, 51, 59 and 108) and pfdhps (codons 437, 540) was examined in parasite isolates by mutation-specific restriction enzyme digestion of nested PCR products. Results A high prevalence of parasites carrying point mutations in all studied targets was found: T76: 93.9% [89.8; 96.7], I51: 96.2% [92.7; 98.4], R59: 93, 9% [89.7; 96.7], N108: 97.6% [94.6; 99.2] and G437: 71.4% [64.8; 77.4]. No mutation was found at codon 540 of the pfdhps gene. The proportion of parasite isolates carrying triple mutation in the pfdhfr gene IRN (I51, R59 andN108) and quadruple mutation on the combination of pfdhfr/pfdhps IRNG (I51, R59, N108 and G437) was 91.5% [86.9; 94.9] and 65.7% [58.9; 72.1], respectively. Analysis of mutation in relation to the clinical status (symptomatic or asymptomatic) and according to age (younger or older than 10 years) showed similar very high frequencies in each category without significant difference between two groups. Conclusions These results suggest a persistence level of resistance of P. falciparum to CQ and SP, seven years after the recommendation of the change of malaria treatment policy in Benin. The distribution of mutations studied was neither related to age nor to clinical status.
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Affiliation(s)
- Aurore Ogouyèmi-Hounto
- Faculté des Sciences de la Santé, Laboratoire du centre de lutte intégrée contre le paludisme, Cotonou 01 BP188, Benin.
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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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Das S, Chakraborty SP, Tripathy S, Hati A, Roy S. Novel quadruple mutations in dihydropteroate synthase genes of Plasmodium falciparum in West Bengal, India. Trop Med Int Health 2012; 17:1329-34. [PMID: 22909027 DOI: 10.1111/j.1365-3156.2012.03071.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To evaluate the anti-folate (sulphadoxine)-resistant pattern in Kolkata, one of the malaria endemic zones of Eastern India. METHODS At first, 107 P. falciparum suspected cases were enrolled in this study. Ninety isolates (84.11%) of 107 suspected cases were analysed, as they had mono-infection with P. falciparum. In vitro susceptibility assays were performed in all 90 isolates. Parasitic DNA was isolated by phenol-chloroform extraction method and polymerase chain reaction was followed by restriction fragment length polymorphism analysis of different codons of the pfdhps gene (436, 437, 540, 581 and 613). RESULTS Among 90 isolates from Kolkata, dhps mutant isolates at codons 436, 437, 540, 581 and 613 were found in 53.33%, 67.78%, 46.66%, 15.56% and 45.55%, respectively. In vitro sulphadoxine resistance was found in 49 isolates (54.44%). Interestingly we found 33 isolates (36.67%) with quadruple AGEAT mutant allele, of which 32 isolates (96.97%) were highly sulphadoxine resistant (P < 0.01) in vitro. CONCLUSION Our present findings implicate that because of enormous drug (sulphfadoxine) pressure, novel AGEAT mutation was highly correlated (P < 0.01) with sulphadoxine resistance.
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Affiliation(s)
- Sabyasachi Das
- Immunology and Microbiology Laboratory, Vidyasagar University, Midnapore, India Division of Parasitology, Calcutta School of Tropical Medicine, Kolkata, India
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Sibley CH, Price RN. Monitoring antimalarial drug resistance: Applying lessons learned from the past in a fast-moving present. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2012; 2:126-33. [PMID: 24533274 DOI: 10.1016/j.ijpddr.2012.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 03/25/2012] [Accepted: 03/28/2012] [Indexed: 11/19/2022]
Abstract
The need for robust surveillance of antimalarial drugs is more urgent than it has ever been. In the western region of Cambodia, artemisinin resistance has emerged in Plasmodium falciparum and threatens to undermine the efficacy of highly effective artemisinin combination therapies. Although some manfestations of artemisinin tolerance are unique to this class of drug, many of its properties mirror previous experience in understanding and tracking resistance to other antimalarials. In this review we outline the spectrum of approaches that were developed to understand the evolution and spread of antifolate resistance, highlighting the importance of integrating information from different methodologies towards a better understanding of the underlying biologic processes. We consider how to apply our experience in investigating and attempting to contain antifolate resistance to inform our prospective assessment of novel antimalarial resistance patterns and their subsequent spread.
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Affiliation(s)
- Carol Hopkins Sibley
- WorldWide Antimalarial Resistance Network, Box 355065, University of Washington, Seattle, WA 98195 5065, USA
| | - Ric N Price
- Global Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia ; Center for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
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Ouédraogo A, Tiono AB, Diarra A, Nébié IO, Konaté AT, Sirima SB. The effects of a pre-season treatment with effective antimalarials on subsequent malaria morbidity in under five-year-old children living in high and seasonal malaria transmission area of Burkina Faso. Trop Med Int Health 2010; 15:1315-21. [PMID: 20958888 DOI: 10.1111/j.1365-3156.2010.02618.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To evaluate the effects of pre-season treatment with single dose of sulfadoxine-pyrimethamine (SP) or artemether-lumefantrine (AL) on subsequent malaria morbidity in under-fives. METHODS A cohort of 156 children was enrolled for longitudinal follow-up. Children received curative therapy with SP or AL, and a third group received no treatment. Participants were home-visited twice a week with blood smears taken from children with fever (axillary T° ≥ 37.5 °C) or history of fever. To assess the time to re-infection, a blood film was also systematically obtained from pre-treated children every 2 weeks. RESULTS The mean time to the first malaria infection was 36 days in the SP arm and 26 days in the AL arm (P=0.006). The incidence density of malaria infection was similar in both groups (86.5%vs. 92.3%, P=0.52). The mean time to the first malaria episode was 47 days in the SP arm and 32 days in the AL arm (P<0.001). The incidence of malaria episodes was significantly higher in the group pre-treated with AL (45.7 per 1000 child days-at-risk CI 95% [35-56]) than in the control group (10.7 per 1000 child days-at-risk CI 95% [7-15]); P<0.001). CONCLUSIONS Our findings suggest that the radical clearance of parasitemia with AL may increase susceptibility to malaria infection and clinical malaria episodes.
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Affiliation(s)
- Alphonse Ouédraogo
- Centre National de Recherche et de Formation sur le Paludisme, Ministère de la Santé, Ouagadougou, Burkina Faso Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
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10
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Beavogui AH, Djimde AA, Gregson A, Toure AM, Dao A, Coulibaly B, Ouologuem D, Fofana B, Sacko A, Tekete M, Kone A, Niare O, Wele M, Plowe CV, Picot S, Doumbo OK. Low infectivity of Plasmodium falciparum gametocytes to Anopheles gambiae following treatment with sulfadoxine-pyrimethamine in Mali. Int J Parasitol 2010; 40:1213-20. [PMID: 20460125 PMCID: PMC3571761 DOI: 10.1016/j.ijpara.2010.04.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 04/19/2010] [Accepted: 04/20/2010] [Indexed: 11/22/2022]
Abstract
Sulfadoxine-pyrimethamine (SP) treatment increases the rate of gametocyte carriage and selects SP resistance-conferring mutations in Plasmodium falciparum dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS), raising concerns of increased malaria transmission and spread of drug resistance. In a setting in Mali where SP was highly efficacious, we measured the prevalence of DHFR and DHPS mutations in P. falciparum infections with microscopy-detected gametocytes following SP treatment, and used direct feeding to assess infectivity to Anopheles gambiae sensu lato. Children and young adults presenting with uncomplicated malaria were treated with SP or chloroquine and followed for 28 days. Gametocyte carriage peaked at 67% 1 week after treatment with a single dose of SP. Those post-SP gametocytes carried significantly more DHFR and DHPS mutations than pre-treatment asexual parasites from the same population. Only 0.5% of 1728 mosquitoes fed on SP-treated gametocyte carriers developed oocysts, while 11% of 198 mosquitoes fed on chloroquine-treated gametocyte carriers were positive for oocysts. This study shows that in an area of high SP efficacy, although SP treatment sharply increased gametocyte carriage, the infectiousness of these gametocytes to the vector may be very low. Accurate and robust methods for measuring infectivity are needed to guide malaria control interventions that affect transmission.
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Affiliation(s)
- Abdoul H. Beavogui
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
- Malaria Research Unit, EA 4170, University Lyon 1, Faculty of Medicine, 8 Avenue Rockefeller, 69373 Lyon, France
| | - Abdoulaye A. Djimde
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
| | - Aric Gregson
- Howard Hughes Medical Institute, Center for Vaccine Development, University of Maryland School of Medicine, 685 W. Baltimore Street, HSF 480, Baltimore, MD 21201, USA
| | - Abdoulaye M. Toure
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
| | - Adama Dao
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
| | - Boubacar Coulibaly
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
| | - Dinkorma Ouologuem
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
| | - Bakary Fofana
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
| | - Adama Sacko
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
| | - Mamadou Tekete
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
| | - Aminatou Kone
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
| | - Oumou Niare
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
| | - Mamadou Wele
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
| | - Christopher V. Plowe
- Howard Hughes Medical Institute, Center for Vaccine Development, University of Maryland School of Medicine, 685 W. Baltimore Street, HSF 480, Baltimore, MD 21201, USA
| | - Stephane Picot
- Malaria Research Unit, EA 4170, University Lyon 1, Faculty of Medicine, 8 Avenue Rockefeller, 69373 Lyon, France
| | - Ogobara K. Doumbo
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, University of Bamako, P.O. Box 1805, Point G, Bamako, Mali
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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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12
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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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13
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Dicko A, Sagara I, Sissoko MS, Guindo O, Diallo AI, Kone M, Toure OB, Sacko M, Doumbo OK. Impact of intermittent preventive treatment with sulphadoxine-pyrimethamine targeting the transmission season on the incidence of clinical malaria in children in Mali. Malar J 2008; 7:123. [PMID: 18611271 PMCID: PMC2500037 DOI: 10.1186/1475-2875-7-123] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Accepted: 07/08/2008] [Indexed: 11/28/2022] Open
Abstract
Background Recent studies have shown that intermittent preventive malaria treatment (IPT) in infants in areas of stable malaria transmission reduces malaria and severe anaemia incidence. However in most areas malaria morbidity and mortality remain high in older children. Methods To evaluate the effect of seasonal IPT with sulphadoxine pyrimethamine (SP) on incidence of malaria disease in area of seasonal transmission, 262 children 6 months-10 years in Kambila, Mali were randomized to receive either IPT with SP twice at eight weeks interval or no IPT during the transmission season of 2002 and were followed up for 12 months. Subjects were also followed during the subsequent transmission season in 2003 to assess possible rebound effect. Clinical malaria cases were treated with SP and followed to assess the in vivo response during both periods. Results The incidence rate of malaria disease per 1,000 person-months during the first 12 months was 3.2 episodes in the treatment group vs. 5.8 episodes in the control group with age-adjusted Protective Efficacy (PE) of 42.5%; [95% CI 28.6%–53.8%]. When the first 16 weeks of follow up is considered age-adjusted PE was 67.5% [95% CI 55.3% – 76.6%]. During the subsequent transmission season, the incidence of clinical malaria per 1000 persons-days was similar between the two groups (23.0 vs 21.5 episodes, age-adjusted IRR = 1.07 [95% CI, 0.90–1.27]). No significant difference was detected in in vivo response between the groups during both periods. Conclusion Two malaria intermittent treatments targeting the peak transmission season reduced the annual incidence rate of clinical malaria by 42.5% in an area with intense seasonal transmission. This simple strategy is likely to be one of the most effectives in reducing malaria burden in such areas. Trial Registration Clinicaltrials.gov NCT00623155
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Affiliation(s)
- Alassane Dicko
- Malaria Research and Training Center, Departments of Epidemiology of Parasitic Diseases, Faculty of Medicine Pharmacy and Dentistry, University of Bamako, P.O. Box 1805, Bamako, Mali.
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14
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Hamel MJ, Poe A, Bloland P, McCollum A, Zhou Z, Shi YP, Ouma P, Otieno K, Vulule J, Escalante A, Udhayakumar V, Slutsker L. Dihydrofolate reductase I164L mutations in Plasmodium falciparum isolates: clinical outcome of 14 Kenyan adults infected with parasites harbouring the I164L mutation. Trans R Soc Trop Med Hyg 2008; 102:338-45. [DOI: 10.1016/j.trstmh.2008.01.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Revised: 01/24/2008] [Accepted: 01/24/2008] [Indexed: 11/25/2022] Open
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Abstract
Malaria persists as an undiminished global problem, but the resources available to address it have increased. Many tools for understanding its biology and epidemiology are well developed, with a particular richness of comparative genome sequences. Targeted genetic manipulation is now effectively combined with in vitro culture assays on the most important human parasite, Plasmodium falciparum, and with in vivo analysis of rodent and monkey malaria parasites in their laboratory hosts. Studies of the epidemiology, prevention, and treatment of human malaria have already been influenced by the availability of molecular methods, and analyses of parasite polymorphisms have long had useful and highly informative applications. However, the molecular epidemiology of malaria is currently undergoing its most substantial revolution as a result of the genomic information and technologies that are available in well-resourced centers. It is a challenge for research agendas to face the real needs presented by a disease that largely exists in extremely resource-poor settings, but it is one that there appears to be an increased willingness to undertake. To this end, developments in the molecular epidemiology of malaria are reviewed here, emphasizing aspects that may be current and future priorities.
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Affiliation(s)
- David J Conway
- Medical Research Council Laboratories, Fajara, P.O. Box 273, Banjul, The Gambia.
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16
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Mita T, Tanabe K, Takahashi N, Tsukahara T, Eto H, Dysoley L, Ohmae H, Kita K, Krudsood S, Looareesuwan S, Kaneko A, Björkman A, Kobayakawa T. Independent evolution of pyrimethamine resistance in Plasmodium falciparum isolates in Melanesia. Antimicrob Agents Chemother 2007; 51:1071-7. [PMID: 17210777 PMCID: PMC1803134 DOI: 10.1128/aac.01186-06] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pyrimethamine resistance in Plasmodium falciparum has previously been shown to have emerged once in Southeast Asia, from where it spread to Africa. Pyrimethamine resistance in this parasite is known to be conferred by mutations in the gene encoding dihydrofolate reductase (dhfr). We have analyzed polymorphisms in dhfr as well as microsatellite haplotypes flanking this gene in a total of 285 isolates from different regions of Melanesia (Papua New Guinea, Vanuatu, and the Solomon Islands) and Southeast Asia (Thailand and Cambodia). Nearly all isolates (92%) in Melanesia were shown to carry a dhfr double mutation (CNRNI [underlining indicates the mutation]) at positions 50, 51, 59, 108, and 164, whereas 98% of Southeast Asian isolates were either triple (CIRNI) or quadruple (CIRNL) mutants. Microsatellite analysis revealed two distinct lineages of dhfr double mutants in Melanesia. One lineage had the same microsatellite haplotype as that previously reported for Southeast Asia and Africa, suggesting the spread of this allele to Melanesia from Southeast Asia. The other lineage had a unique, previously undescribed microsatellite haplotype, indicative of the de novo emergence of pyrimethamine resistance in Melanesia.
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Affiliation(s)
- Toshihiro Mita
- Department of International Affairs and Tropical Medicine, Tokyo Women's Medical University School of Medicine, 9-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
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de Radiguès X, Diallo KI, Diallo M, Ngwakum PA, Maiga H, Djimdé A, Sacko M, Doumbo O, Guthmann JP. Efficacy of chloroquine and sulfadoxine/pyrimethamine for the treatment of uncomplicated falciparum malaria in Koumantou, Mali. Trans R Soc Trop Med Hyg 2006; 100:1013-8. [PMID: 16765395 DOI: 10.1016/j.trstmh.2006.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Revised: 03/29/2006] [Accepted: 03/29/2006] [Indexed: 11/29/2022] Open
Abstract
We report the results of an in vivo antimalarial efficacy study with chloroquine (CQ) and sulfadoxine/pyrimethamine (SP) conducted between 2003 and 2004 in Koumantou, southern Mali. A total of 244 children were included in the study; 210 children were followed-up for 28 days according to WHO recommendations, with PCR genotyping to distinguish late recrudescence from re-infection. Global failure proportions at Day 14, without taking into account re-infections, were 44.2% (95% CI 34.9-53.5%) in the CQ group and 2.0% (95% CI 0.0-4.8%) in the SP group. PCR-adjusted failure proportions at Day 28 were even higher in the CQ group (90.5% (95/105), 95% CI 84.8-96.2%) and relatively low in the SP group (7.0% (7/100), 95% CI 1.9-12.1%). These results show that CQ is no longer efficacious in Koumantou. The use of SP in monotherapy is likely to compromise its efficacy. We recommend the use of artemisinin-based combination therapy as first-line treatment for uncomplicated Plasmodium falciparum malaria in Koumantou.
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18
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Thera MA, Sehdev PS, Coulibaly D, Traore K, Garba MN, Cissoko Y, Kone A, Guindo A, Dicko A, Beavogui AH, Djimde AA, Lyke KE, Diallo DA, Doumbo OK, Plowe CV. Impact of trimethoprim-sulfamethoxazole prophylaxis on falciparum malaria infection and disease. J Infect Dis 2005; 192:1823-9. [PMID: 16235184 PMCID: PMC2740817 DOI: 10.1086/498249] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2005] [Accepted: 09/19/2005] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Trimethoprim-sulfamethoxazole (TS) prophylaxis is recommended for persons living with human immunodeficiency virus infection and acquired immunodeficiency syndrome in Africa. TS and the antimalarial combination sulfadoxine-pyrimethamine (SP) share mechanisms of action and resistance patterns, and concerns about the impact of TS resistance on SP efficacy have contributed to reluctance to implement TS prophylaxis in Africa. METHODS To determine whether TS prophylaxis impairs SP efficacy for treatment of uncomplicated falciparum malaria, we conducted a randomized, controlled, open-label study of TS prophylaxis. Two hundred and forty children 5-15 years old were randomized in a 2 : 1 fashion to receive either thrice-weekly TS for 12 weeks or no prophylaxis and were treated with SP for subsequent episodes of malaria. The incidence of malaria, SP efficacy, and the prevalence of parasite mutations that confer antifolate drug resistance were measured. RESULTS TS prophylaxis had a 99.5% protective efficacy against episodes of clinical malaria, with 97% efficacy against infection. Four SP treatment failures occurred in the control group, and none occurred in the TS group. No evidence was seen for selection by TS of antifolate resistance-conferring mutations in parasite dihydrofolate reductase or dihydropteroate synthase during subclinical infections. CONCLUSIONS In this setting of low antifolate resistance, TS was highly effective in preventing falciparum malaria infection and disease and did not appear to select for SP-resistant parasites.
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Affiliation(s)
- Mahamadou A Thera
- Bandiagara Malaria Project, Malaria Research and Training Center, University of Bamako, Mali
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19
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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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Gregson A, Plowe CV. Mechanisms of resistance of malaria parasites to antifolates. Pharmacol Rev 2005; 57:117-45. [PMID: 15734729 DOI: 10.1124/pr.57.1.4] [Citation(s) in RCA: 309] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Antifolate antimalarial drugs interfere with folate metabolism, a pathway essential to malaria parasite survival. This class of drugs includes effective causal prophylactic and therapeutic agents, some of which act synergistically when used in combination. Unfortunately, the antifolates have proven susceptible to resistance in the malaria parasite. Resistance is caused by point mutations in dihydrofolate reductase and dihydropteroate synthase, the two key enzymes in the folate biosynthetic pathway that are targeted by the antifolates. Resistance to these drugs arises relatively rapidly in response to drug pressure and is now common worldwide. Nevertheless, antifolate drugs remain first-line agents in several sub-Saharan African countries where chloroquine resistance is widespread, at least partially because they remain the only affordable, effective alternative. New antifolate combinations that are more effective against resistant parasites are being developed and in one case, recently introduced into use. Combining these antifolates with drugs that act on different targets in the parasite should greatly enhance their effectiveness as well as deter the development of resistance. Molecular epidemiological techniques for monitoring parasite drug resistance may contribute to development of strategies for prolonging the useful therapeutic life of this important class of drugs.
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Affiliation(s)
- Aric Gregson
- Malaria Section, Center for Vaccine Development, University of Maryland School of Medicine, 685 West Baltimore Street, HSF1 Room 480, Baltimore, MD 21201, USA
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21
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Mbaisi A, Liyala P, Eyase F, Achilla R, Akala H, Wangui J, Mwangi J, Osuna F, Alam U, Smoak BL, Davis JM, Kyle DE, Coldren RL, Mason C, Waters NC. Drug susceptibility and genetic evaluation of Plasmodium falciparum isolates obtained in four distinct geographical regions of Kenya. Antimicrob Agents Chemother 2004; 48:3598-601. [PMID: 15328137 PMCID: PMC514731 DOI: 10.1128/aac.48.9.3598-3601.2004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The drug resistance profiles of Plasmodium falciparum isolated from four regions in Kenya were analyzed for drug resistance profiles. We observed variability in resistance to a broad range of antimalarial drugs across Kenya as determined from in vitro drug susceptibility screening and genotyping analysis.
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22
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Plowe CV. Monitoring antimalarial drug resistance: making the most of the tools at hand. ACTA ACUST UNITED AC 2004; 206:3745-52. [PMID: 14506209 DOI: 10.1242/jeb.00658] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Most countries in resource-poor, malaria-endemic areas lack current and comprehensive information on antimalarial drug efficacy, resulting in sub-optimal antimalarial treatment policies. Many African countries continue to use chloroquine despite very high rates of resistance, and others have changed policies based on limited data, with mixed success. Methods for measuring antimalarial drug efficacy and resistance include in vivo studies of clinical efficacy and parasitological resistance, in vitro susceptibility assays and molecular markers for resistance to some drugs. These methods have the potential to be used in an integrated fashion to provide timely information that is useful to policy makers, and the combined use of in vivo and molecular surveys could greatly extend the coverage of resistance monitoring. Malawi, the first African country to change from chloroquine to sulfadoxine/pyrimethamine at the national level, serves as a case study for resistance monitoring and evidence-based antimalarial policies. Molecular, in vitro and in vivo studies demonstrate that chloroquine-sensitive parasites reemerged and now predominate in Malawi after it switched from chloroquine to sulfadoxine/pyrimethamine. This raises the intriguing possibility of rotating antimalarial drugs.
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Affiliation(s)
- Christopher V Plowe
- Malaria Section, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Müller O, Traore C, Kouyate B. Efficacy of pyrimethamine-sulfadoxine in young children with uncomplicated falciparum malaria in rural Burkina Faso. Malar J 2004; 3:10. [PMID: 15134583 PMCID: PMC419363 DOI: 10.1186/1475-2875-3-10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Accepted: 05/11/2004] [Indexed: 11/12/2022] Open
Abstract
The efficacy of pyrimethamine-sulfadoxine in the treatment of uncomplicated falciparum malaria in young children of a malaria holoendemic area in rural Burkina Faso is reported. Of 28 children treated with a standard single dose of pyrimethamine-sulfadoxine and followed-up over 14 days, only one Late Treatment Failure and four Late Parasitological Failures were observed, all with low-grade parasitaemia. In this area of very restricted use of pyrimethamine-sulfadoxine, the drug appears to be still sufficiently effective in the treatment of malaria. These findings provide further evidence for the justification of continued use of pyrimethamine-sulfadoxine as a second-line treatment for malaria in Burkina Faso.
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Affiliation(s)
- Olaf Müller
- Department of Tropical Hygiene and Public Health of the Ruprecht-Karls-University Heidelberg, Heidelberg, Germany
| | | | - Bocar Kouyate
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
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Sowunmi A, Fehintola FA, Adedeji AA, Gbotosho GO, Falade CO, Tambo E, Fateye BA, Happi TC, Oduola AMJ. Open randomized study of pyrimethamine-sulphadoxine vs. pyrimethamine-sulphadoxine plus probenecid for the treatment of uncomplicated Plasmodium falciparum malaria in children. Trop Med Int Health 2004; 9:606-14. [PMID: 15117306 DOI: 10.1111/j.1365-3156.2004.01233.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Increasing drug resistance in Plasmodium falciparum has necessitated renewed search for cheap, effective alternatives to commonly available antimalarials, chloroquine and pyrimethamine-sulphadoxine, for the treatment of malaria in Africa. Probenecid, an inhibitor of organic anion transporters and multiresistance-associated proteins, can chemosensitize P. falciparum to pyrimethamine and sulphadoxine in vitro, but the clinical significance is unclear. We assessed the safety, treatment efficacy, and effects on gametocyte carriage of adding probenecid to pyrimethamine-sulphadoxine. METHODS We evaluated 151 children aged 12 years or younger who had uncomplicated P. falciparum malaria. Patients were randomly assigned pyrimethamine-sulphadoxine (25 mg/kg of the sulphadoxine component) or pyrimethamine-sulphadoxine as above plus probenecid 20-25 mg/kg of bodyweight in two divided doses daily for 3 days. The primary endpoints were parasitological cure rates on days 14 and 28. RESULTS Both regimens were well tolerated; no child was withdrawn because of drug intolerance. Fever (1.9 +/- 1.1 vs. 2.4 +/- 1.2 days, P = 0.02) and parasite clearance (2.3 +/- 0.9 vs. 2.7 +/- 1.1 days, P = 0.04) were significantly shorter, and the parasitological cure rate on day 14 (96.2%vs. 83.5%, P = 0.02) but not day 28 (79.4%vs. 72.6%, P = 0.4), was significantly higher in children treated with pyrimethamine-sulphadoxine-probenecid than in those treated with pyrimethamine-sulphadoxine. Gametocyte carriage was similar with both treatment regimens. CONCLUSIONS The combination of pyrimethamine-sulphadoxine, and probenecid, at a relatively moderate dose, improved treatment efficacy but had no effect on gametocyte carriage. The pyrimethamine-sulphadoxine-probenecid combination merits further evaluation as a potential treatment for use in Nigeria.
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Affiliation(s)
- A Sowunmi
- Department of Pharmacology & Therapeutics and Institute for Medical Research and Training, University of Ibadan, Ibadan, Nigeria.
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Talisuna AO, Bloland P, D'Alessandro U. History, dynamics, and public health importance of malaria parasite resistance. Clin Microbiol Rev 2004; 17:235-54. [PMID: 14726463 PMCID: PMC321461 DOI: 10.1128/cmr.17.1.235-254.2004] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Despite considerable efforts, malaria is still one of the most devastating infectious diseases in the tropics. The rapid spread of antimalarial drug resistance currently compounds this grim picture. In this paper, we review the history of antimalarial drug resistance and the methods for monitoring it and assess the current magnitude and burden of parasite resistance to two commonly used drugs: chloroquine and sulfadoxine-pyrimethamine. Furthermore, we review the factors involved in the emergence and spread of drug resistance and highlight its public health importance. Finally, we discuss ways of dealing with such a problem by using combination therapy and suggest some of the research themes needing urgent answers.
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Affiliation(s)
- Ambrose O Talisuna
- Ministry of Health, Epidemiological Surveillance Division, Kampala, Uganda
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Sowunmi A, Fateye BA. Gametocyte sex ratios in children with asymptomatic, recrudescent, pyrimethamine-sulfadoxine-resistant, Plasmodium falciparum malaria. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2004; 97:671-82. [PMID: 14613626 DOI: 10.1179/000349803225002381] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The clinical features of the primary Plasmodium falciparum infections in 25 children, and of the recrudescent infections that emerged after pyrimethamine-sulfadoxine (PS) treatment of the children had failed, were evaluated. In addition, the gametocyte sex ratios in these children and in age- and gender-matched controls who had PS-sensitive (PS-S) infections were also examined. Compared with the primary infections, the recrudescent infections were accompanied by significantly fewer symptoms and lower levels of parasitaemia but significantly higher gametocytaemia:parasitaemia ratios. Although the mean gametocyte sex ratio was female-biased pre-treatment, in both the PS-resistant (PS-R) and PS-S infections it became male-biased on days 7 and 14 post-treatment. The times taken to attain a sex ratio of 1 were similar in both groups. The predominance of macrogametocytes seen 'early' post-treatment (on day 3) was later replaced by a predominance of microgametocytes (on days 7 and 14). Analysis of the disposition of gametocytaemia, from the time to attain a sex ratio of 1, showed that the area under the curve of the plot of the level of microgametocytaemia upsilon. time and the mean half-life of the microgametocytaemia were significantly greater and microgametocytaemia clearance was significantly slower than the corresponding values for macrogametocytaemia. Although sex ratios in Plasmodium may naturally become more male-biased as the infection progresses, it is possible that PS treatment may have contributed to the male-biased sex ratios observed post-treatment.
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Affiliation(s)
- A Sowunmi
- Department of Pharmacology and Therapeutics and Institute for Medical Research and Training, University of Ibadan, Ibadan, Nigeria.
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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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28
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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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29
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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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30
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Tinto H, Zoungrana EB, Coulibaly SO, Ouedraogo JB, Traoré M, Guiguemde TR, Van Marck E, D'Alessandro U. Chloroquine and sulphadoxine-pyrimethamine efficacy for uncomplicated malaria treatment and haematological recovery in children in Bobo-Dioulasso, Burkina Faso during a 3-year period 1998-2000. Trop Med Int Health 2002; 7:925-30. [PMID: 12390597 DOI: 10.1046/j.1365-3156.2002.00952.x] [Citation(s) in RCA: 19] [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
We determined the parasitological resistance and the clinical failure to chloroquine (CQ) and sulphadoxine-pyrimethamine (SP) by the WHO 14-day in vivo test over three consecutive years in 948 children aged 6-59 months with uncomplicated malaria attending four health centres in the province of Houet, Burkina Faso. Children were alternatively allocated to either CQ or SP. Packed cell volume (PCV) was measured at days 0 and 14. Parasitological resistance (RI, RII and RIII) to CQ was 18% (83 of 455) and to SP <1% (two of 308). Clinical failure with CQ was 12% (53 of 455) with no evidence of increase over time. Only one case of clinical failure was detected among the children treated with SP. The prevalence of anaemia (PCV <25%) was about 40% at day 0 and had decreased substantially by day 14 in both groups. However, in children treated with SP the prevalence of anaemia at day 14 was significantly lower than in those treated with CQ:RR = 3.15 (95% CI: 1.33-7.42, P = 0.008). CQ and SP are still efficacious for the treatment of uncomplicated malaria in children, at least in this area of Burkina Faso. However, the prevalences of CQ resistance reported from other areas of the country are worrying because of its potential spread. Regular surveillance of resistance to commonly used antimalarial drugs should continue.
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Affiliation(s)
- H Tinto
- Centre Muraz, Bobo-Dioulasso, Burkina Faso, Africa.
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31
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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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32
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Abstract
Resistance to antifolates of the malaria parasite Plasmodium falciparum stems from stepwise mutations of the target enzyme dihydrofolate reductase (DHFR). New drugs can be developed against resistant parasites, which are assumed to have limited possibilities in mutations. Mechanisms of resistance other than reduced binding of inhibitors to mutant enzymes may be possible and need to be further explored. New synergistic combinations of drugs targeting DHFR and dihydropteroate synthase may be employed, with new provisions against development of resistance.
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Affiliation(s)
- Yongyuth Yuthavong
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Rama 6 Road, 10400, Bangkok, Thailand.
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Sibley CH, Hyde JE, Sims PF, Plowe CV, Kublin JG, Mberu EK, Cowman AF, Winstanley PA, Watkins WM, Nzila AM. Pyrimethamine–sulfadoxine resistance in Plasmodium falciparum: what next? Trends Parasitol 2001. [DOI: 10.1016/s1471-4922(01)02185-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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34
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Sibley CH, Hyde JE, Sims PF, Plowe CV, Kublin JG, Mberu EK, Cowman AF, Winstanley PA, Watkins WM, Nzila AM. Pyrimethamine-sulfadoxine resistance in Plasmodium falciparum: what next? Trends Parasitol 2001; 17:582-8. [PMID: 11756042 DOI: 10.1016/s1471-4922(01)02085-2] [Citation(s) in RCA: 252] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Chemotherapy remains the only practicable tool to control falciparum malaria in sub-Saharan Africa, where >90% of the world's burden of malaria mortality and morbidity occurs. Resistance is rapidly eroding the efficacy of chloroquine, and the combination pyrimethamine-sulfadoxine is the most commonly chosen alternative. Resistant populations of Plasmodium falciparum were selected extremely rapidly in Southeast Asia and South America. If this happens in sub-Saharan Africa, it will be a public health disaster because no inexpensive alternative is currently available. This article reviews the molecular mechanisms of this resistance and discusses how to extend the therapeutic life of antifolate drugs.
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Affiliation(s)
- C H Sibley
- Department of Genetics, Box 357360, University of Washington, Seattle, WA 98195-7360, USA.
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35
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Chaparro J, Rojas MO, Wasserman M. Plasmodium falciparum: underestimation of dihydrofolate reductase and dihydropteroate synthase polymorphism in field samples: a technical shortcoming of nested PCR assays with mutation-specific primers. Exp Parasitol 2001; 99:115-22. [PMID: 11846521 DOI: 10.1006/expr.2001.4660] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
n a study parallel to the present one, we conducted a genotype characterization of Plasmodium falciparum based on isolates of patients infected with malaria, who come from a small location in Colombia. The analysis involved extraction of DNA from hematological smears, amplification of the dihydrofolate reductase gene and the dihydropteroate synthase (DHPS) gene for each sample by PCR, and detection through mutation-specific primers nested PCR of mutations associated with resistance to pyrimethamine and sulfadoxine. Given the difficulty in quantifying the DNA extracts due to the type of sample and its heterogeneity, different volumes of the product of the first PCR were tested as template for the nested PCR. Surprisingly, for some samples, we found contradictory results between determinations, which differed only in the amount of template used. This prompted a more general concern that in a natural isolate, where the parasite population is heterogeneous, the nested PCR with mutation-specific primers technique can produce erroneous results that underestimate the complexity of the sample. To test this hypothesis, we designed experiments in this study using position 581 of the DHPS gene as an indicator system and constructed samples simulating the heterogeneity of natural samples. In effect, our data show that the results obtained in the nested PCR can be altered by the amount of template used in the reaction and, therefore, some heterogeneous samples might be classified mistakenly as homogeneous, simple mutant or simple wild type. These observations may explain, at least in part, contradictory results found in the literature. Our data also suggest the need for a more cautious approach to interpretation of the results of nested PCR assays with mutation-specific primers and their implications in the definition of resistance to the pyrimethamine-sulfadoxine combination.
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Affiliation(s)
- J Chaparro
- Laboratory of Biochemistry, Instituto Nacional de Salud, Av. Eldorado Cra. 50, Bogotá, Colombia
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36
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Mawili-Mboumba DP, Ekala MT, Lekoulou F, Ntoumi F. Molecular analysis of DHFR and DHPS genes in P. falciparum clinical isolates from the Haut--Ogooué region in Gabon. Acta Trop 2001; 78:231-40. [PMID: 11311186 DOI: 10.1016/s0001-706x(01)00084-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The main objective of this work was to determine the prevalence of mutations in genes coding for the dihydropteroate synthase (DHPS) and the dihydrofolate reductase (DHFR) enzymes which are implicated in resistance of P. falciparum to antifolate (pyrimethamine-sulfadoxine (P/S)). In this study, 117 human blood samples were collected at Franceville located in the region of Haut-Ogooué (South-eastern Gabon). In this area, a relatively low level of sensitivity of Plasmodium falciparum to P/S has been reported with 18.2% of RII and 12.1% of RI resistance. A nested polymerase chain reaction was used to amplify a fragment of the DHFR gene containing codon 108, where a point mutation causing a Serine (wild type) to Asparagine or to a Threonine (resistant types) change occurs in pyrimethamine resistant parasites. Eleven DHFR fragments were sequenced and mutations occurring at codons 51, 59 and 108 were analysed. The DHPS gene was amplified by polymerase chain reaction (PCR) and sequenced directly or after cloning. Variant amino acid residues 436, 437, 540, 581, 613 associated with sulfadoxine resistance were analysed. The analysis of codon 108 of the DHFR gene was undertaken for 81 isolates. More than one DHFR P. falciparum genotype was present in 64% of the samples. We showed that 47% of 141 DHFR gene PCR products had Serine (wild phenotype), and 52% had Asparagine. We found one isolate with the Thr-108 confirmed by sequencing of the PCR product. Triple, double and single DHFR mutant at positions 51, 59 and 108 were found. Only codons 436 and 437 of the 38 analysed sequences of the DHPS gene revealed point mutations. These results have been compared with those reported from different sites in Africa, Asia or South-America.
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Affiliation(s)
- D P Mawili-Mboumba
- Centre International de Recherches Médicales de Franceville, BP 769, Franceville, Gabon
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37
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Nzila AM, Mberu EK, Sulo J, Dayo H, Winstanley PA, Sibley CH, Watkins WM. Towards an understanding of the mechanism of pyrimethamine-sulfadoxine resistance in Plasmodium falciparum: genotyping of dihydrofolate reductase and dihydropteroate synthase of Kenyan parasites. Antimicrob Agents Chemother 2000; 44:991-6. [PMID: 10722502 PMCID: PMC89803 DOI: 10.1128/aac.44.4.991-996.2000] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antifolate combination of pyrimethamine (PM) and sulfadoxine (SD) is the last affordable drug combination available for wide-scale treatment of falciparum malaria in Africa. Wherever this combination has been used, drug-resistant parasites have been selected rapidly. A study of PM-SD effectiveness carried out between 1997 and 1999 at Kilifi on the Kenyan coast has shown the emergence of RI and RII resistance to PM-SD (residual parasitemia 7 days after treatment) in 39 out of 240 (16.25%) patients. To understand the mechanism that underlies resistance to PM-SD, we have analyzed the dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) genotypes of 81 patients. Fifty-one samples were obtained, before treatment, from patients who remained parasite free for at least 7 days after treatment. For a further 20 patients, samples were obtained before treatment and again when they returned to the clinic with parasites 7 days after PM-SD treatment. Ten additional isolates were obtained from patients who were parasitemic 7 days after treatment but who were not sampled before treatment. More than 65% of the isolates (30 of 46) in the initial group had wild-type or double mutant DHFR alleles, and all but 7 of the 47 (85%) had wild-type DHPS alleles. In the paired (before and after treatment) samples, the predominant combinations of DHFR and DHPS alleles before treatment were of triple mutant DHFR and double mutant DHPS (41% [7 of 17]) and of double mutant DHFR and double mutant DHPS (29% [5 of 17]). All except one of the posttreatment isolates had triple mutations in DHFR, and most of these were "pure" triple mutants. In these isolates, the combination of a triple mutant DHFR and wild-type DHPS was detected in 6 of 29 cases (20.7%), the combination of a triple mutant DHFR and a single mutant (A437G) DHPS was detected in 4 of 29 cases (13.8%), and the combination of a triple mutant DHFR and a double mutant (A437G, L540E) DHPS was detected in 16 of 29 cases (55.2%). These results demonstrate that the triply mutated allele of DHFR with or without mutant DHPS alleles is associated with RI and RII resistance to PM-SD. The prevalence of the triple mutant DHFR-double mutant DHPS combination may be an operationally useful marker for predicting the effectiveness of PM-SD as a new malaria treatment.
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Affiliation(s)
- A M Nzila
- Kenya Medical Research Institute/Wellcome Trust Collaborative Research Program, Wellcome Trust Research Laboratories, Nairobi, UK.
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