1
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Balta VA, Stiffler D, Sayeed A, Tripathi AK, Elahi R, Mlambo G, Bakshi RP, Dziedzic AG, Jedlicka AE, Nenortas E, Romero-Rodriguez K, Canonizado MA, Mann A, Owen A, Sullivan DJ, Prigge ST, Sinnis P, Shapiro TA. Clinically relevant atovaquone-resistant human malaria parasites fail to transmit by mosquito. Nat Commun 2023; 14:6415. [PMID: 37828012 PMCID: PMC10570281 DOI: 10.1038/s41467-023-42030-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 09/27/2023] [Indexed: 10/14/2023] Open
Abstract
Long-acting injectable medications, such as atovaquone, offer the prospect of a "chemical vaccine" for malaria, combining drug efficacy with vaccine durability. However, selection and transmission of drug-resistant parasites is of concern. Laboratory studies have indicated that atovaquone resistance disadvantages parasites in mosquitoes, but lack of data on clinically relevant Plasmodium falciparum has hampered integration of these variable findings into drug development decisions. Here we generate atovaquone-resistant parasites that differ from wild type parent by only a Y268S mutation in cytochrome b, a modification associated with atovaquone treatment failure in humans. Relative to wild type, Y268S parasites evidence multiple defects, most marked in their development in mosquitoes, whether from Southeast Asia (Anopheles stephensi) or Africa (An. gambiae). Growth of asexual Y268S P. falciparum in human red cells is impaired, but parasite loss in the mosquito is progressive, from reduced gametocyte exflagellation, to smaller number and size of oocysts, and finally to absence of sporozoites. The Y268S mutant fails to transmit from mosquitoes to mice engrafted with human liver cells and erythrocytes. The severe-to-lethal fitness cost of clinically relevant atovaquone resistance to P. falciparum in the mosquito substantially lessens the likelihood of its transmission in the field.
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Affiliation(s)
- Victoria A Balta
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Deborah Stiffler
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Abeer Sayeed
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Abhai K Tripathi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Rubayet Elahi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Godfree Mlambo
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Rahul P Bakshi
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186, USA
| | - Amanda G Dziedzic
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Anne E Jedlicka
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Elizabeth Nenortas
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186, USA
| | - Keyla Romero-Rodriguez
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186, USA
| | - Matthew A Canonizado
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186, USA
| | - Alexis Mann
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Andrew Owen
- Centre of Excellence in Long-acting Therapeutics (CELT), Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool, L69 3BX, UK
| | - David J Sullivan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Sean T Prigge
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Photini Sinnis
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Theresa A Shapiro
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA.
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA.
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186, USA.
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Castañeda-Mogollón D, Toppings NB, Kamaliddin C, Lang R, Kuhn S, Pillai DR. Amplicon Deep Sequencing Reveals Multiple Genetic Events Lead to Treatment Failure with Atovaquone-Proguanil in Plasmodium falciparum. Antimicrob Agents Chemother 2023; 67:e0170922. [PMID: 37154745 PMCID: PMC10269153 DOI: 10.1128/aac.01709-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/05/2023] [Indexed: 05/10/2023] Open
Abstract
Atovaquone-proguanil (AP) is used as treatment for uncomplicated malaria, and as a chemoprophylactic agent against Plasmodium falciparum. Imported malaria remains one of the top causes of fever in Canadian returning travelers. Twelve sequential whole-blood samples before and after AP treatment failure were obtained from a patient diagnosed with P. falciparum malaria upon their return from Uganda and Sudan. Ultradeep sequencing was performed on the cytb, dhfr, and dhps markers of treatment resistance before and during the episode of recrudescence. Haplotyping profiles were generated using three different approaches: msp2-3D7 agarose and capillary electrophoresis, and cpmp using amplicon deep sequencing (ADS). A complexity of infection (COI) analysis was conducted. De novo cytb Y268C mutants strains were observed during an episode of recrudescence 17 days and 16 h after the initial malaria diagnosis and AP treatment initiation. No Y268C mutant reads were observed in any of the samples prior to the recrudescence. SNPs in the dhfr and dhps genes were observed upon initial presentation. The haplotyping profiles suggest multiple clones mutating under AP selection pressure (COI > 3). Significant differences in COI were observed by capillary electrophoresis and ADS compared to the agarose gel results. ADS using cpmp revealed the lowest haplotype variation across the longitudinal analysis. Our findings highlight the value of ultra-deep sequencing methods in the understanding of P. falciparum haplotype infection dynamics. Longitudinal samples should be analyzed in genotyping studies to increase the analytical sensitivity.
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Affiliation(s)
- Daniel Castañeda-Mogollón
- Cumming School of Medicine, Department of Pathology & Laboratory Medicine, the University of Calgary, Calgary, Alberta, Canada
- Cumming School of Medicine, Department of Microbiology, Immunology, and Infectious Diseases, the University of Calgary, Calgary, Alberta, Canada
- Calvin, Phoebe & Joan Snyder Institute for Chronic Diseases, the University of Calgary, Calgary, Alberta, Canada
| | - Noah B. Toppings
- Cumming School of Medicine, Department of Pathology & Laboratory Medicine, the University of Calgary, Calgary, Alberta, Canada
- Cumming School of Medicine, Department of Microbiology, Immunology, and Infectious Diseases, the University of Calgary, Calgary, Alberta, Canada
- Calvin, Phoebe & Joan Snyder Institute for Chronic Diseases, the University of Calgary, Calgary, Alberta, Canada
| | - Claire Kamaliddin
- Cumming School of Medicine, Department of Pathology & Laboratory Medicine, the University of Calgary, Calgary, Alberta, Canada
- Cumming School of Medicine, Department of Microbiology, Immunology, and Infectious Diseases, the University of Calgary, Calgary, Alberta, Canada
- Calvin, Phoebe & Joan Snyder Institute for Chronic Diseases, the University of Calgary, Calgary, Alberta, Canada
| | - Raynell Lang
- Cumming School of Medicine, Department of Medicine, the University of Calgary, Calgary, Alberta, Canada
- Cumming School of Medicine, Department of Community Health Sciences, the University of Calgary, Calgary, Alberta, Canada
| | - Susan Kuhn
- Cumming School of Medicine, Department of Pediatrics, the University of Calgary, Calgary, Alberta, Canada
| | - Dylan R. Pillai
- Cumming School of Medicine, Department of Pathology & Laboratory Medicine, the University of Calgary, Calgary, Alberta, Canada
- Cumming School of Medicine, Department of Microbiology, Immunology, and Infectious Diseases, the University of Calgary, Calgary, Alberta, Canada
- Calvin, Phoebe & Joan Snyder Institute for Chronic Diseases, the University of Calgary, Calgary, Alberta, Canada
- Alberta Precision Laboratories, Diagnostic & Scientific Centre, Calgary, Alberta, Canada
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3
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Balta VA, Stiffler D, Sayeed A, Tripathi AK, Elahi R, Mlambo G, Bakshi RP, Dziedzic AG, Jedlicka AE, Nenortas E, Romero-Rodriguez K, Canonizado MA, Mann A, Owen A, Sullivan DJ, Prigge ST, Sinnis P, Shapiro TA. Transmissibility of clinically relevant atovaquone-resistant Plasmodium falciparum by anopheline mosquitoes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.07.527535. [PMID: 36798298 PMCID: PMC9934642 DOI: 10.1101/2023.02.07.527535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Rising numbers of malaria cases and deaths underscore the need for new interventions. Long-acting injectable medications, such as those now in use for HIV prophylaxis, offer the prospect of a malaria "chemical vaccine", combining the efficacy of a drug (like atovaquone) with the durability of a biological vaccine. Of concern, however, is the possible selection and transmission of drug-resistant parasites. We addressed this question by generating clinically relevant, highly atovaquone-resistant, Plasmodium falciparum mutants competent to infect mosquitoes. Isogenic paired strains, that differ only by a single Y268S mutation in cytochrome b, were evaluated in parallel in southeast Asian (Anopheles stephensi) or African (Anopheles gambiae) mosquitoes, and thence in humanized mice. Fitness costs of the mutation were evident along the lifecycle, in asexual parasite growth in vitro and in a progressive loss of parasites in the mosquito. In numerous independent experiments, microscopic exam of salivary glands from hundreds of mosquitoes failed to detect even one Y268S sporozoite, a defect not rescued by coinfection with wild type parasites. Furthermore, despite uniformly successful transmission of wild type parasites from An. stephensi to FRG NOD huHep mice bearing human hepatocytes and erythrocytes, multiple attempts with Y268S-fed mosquitoes failed: there was no evidence of parasites in mouse tissues by microscopy, in vitro culture, or PCR. These studies confirm a severe-to-lethal fitness cost of clinically relevant atovaquone-resistant P. falciparum in the mosquito, and they significantly lessen the likelihood of their transmission in the field.
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Affiliation(s)
- Victoria A. Balta
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Deborah Stiffler
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Abeer Sayeed
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Abhai K. Tripathi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Rubayet Elahi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Godfree Mlambo
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Rahul P. Bakshi
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186
| | - Amanda G. Dziedzic
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
| | - Anne E. Jedlicka
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
| | - Elizabeth Nenortas
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186
| | - Keyla Romero-Rodriguez
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186
| | - Matthew A. Canonizado
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186
| | - Alexis Mann
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Andrew Owen
- Centre of Excellence in Long-acting Therapeutics (CELT), Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool L69 3BX, UK
| | - David J. Sullivan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Sean T. Prigge
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Photini Sinnis
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Theresa A. Shapiro
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186
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Kariyawasam R, Lau R, Shao E, Tan K, Showler A, Ralevski F, Patel SN, Boggild AK. Molecular Surveillance for Imported Antimicrobial Resistant Plasmodium falciparum, Ontario, Canada. Emerg Infect Dis 2022; 28:812-819. [PMID: 35318914 PMCID: PMC8962893 DOI: 10.3201/eid2804.210533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Single-nucleotide polymorphisms at several loci have been correlated with Plasmodium falciparum drug resistance. We examined the prevalence of resistance markers in P. falciparum from imported malaria cases in Canada during 3 time periods, 2008-2009, 2013-2014, and 2017-2018. We evaluated single-nucleotide polymorphisms at atpase6 (pfATPase6), pfcrt (chloroquine resistance transporter), cytb (cytochrome b), dhfr (dihydrofolate reductase), dhps (dihydropteroate synthetase), mdr1 (multidrug resistance protein) and mdr1 copy number, and kelch13 (kelch protein gene on chromosome 13). Over time, we observed increasing mutant genotypes for dhfr S108N and dhps A613T and decreasing mutant genotypes for mdr1 N86Y, D1246Y, pfcrt K76T, and pfcrt 74-75; we identified no kelch13 mutations. We observed fewer mutations indicative of chloroquine resistance over time, which may reflect reduced chloroquine pressure in specimens from travelers to Africa. Mutations conferring proguanil resistance increased over time. Minor genotypes confirm the heterogeneous nature of infection and may affect treatment success.
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Chebon-Bore L, Sanyanga TA, Manyumwa CV, Khairallah A, Tastan Bishop Ö. Decoding the Molecular Effects of Atovaquone Linked Resistant Mutations on Plasmodium falciparum Cytb-ISP Complex in the Phospholipid Bilayer Membrane. Int J Mol Sci 2021; 22:2138. [PMID: 33670016 PMCID: PMC7926518 DOI: 10.3390/ijms22042138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/02/2021] [Accepted: 02/07/2021] [Indexed: 12/19/2022] Open
Abstract
Atovaquone (ATQ) is a drug used to prevent and treat malaria that functions by targeting the Plasmodium falciparum cytochrome b (PfCytb) protein. PfCytb catalyzes the transmembrane electron transfer (ET) pathway which maintains the mitochondrial membrane potential. The ubiquinol substrate binding site of the protein has heme bL, heme bH and iron-sulphur [2FE-2S] cluster cofactors that act as redox centers to aid in ET. Recent studies investigating ATQ resistance mechanisms have shown that point mutations of PfCytb confer resistance. Thus, understanding the resistance mechanisms at the molecular level via computational approaches incorporating phospholipid bilayer would help in the design of new efficacious drugs that are also capable of bypassing parasite resistance. With this knowledge gap, this article seeks to explore the effect of three drug resistant mutations Y268C, Y268N and Y268S on the PfCytb structure and function in the presence and absence of ATQ. To draw reliable conclusions, 350 ns all-atom membrane (POPC:POPE phospholipid bilayer) molecular dynamics (MD) simulations with derived metal parameters for the holo and ATQ-bound -proteins were performed. Thereafter, simulation outputs were analyzed using dynamic residue network (DRN) analysis. Across the triplicate MD runs, hydrophobic interactions, reported to be crucial in protein function were assessed. In both, the presence and absence of ATQ and a loss of key active site residue interactions were observed as a result of mutations. These active site residues included: Met 133, Trp136, Val140, Thr142, Ile258, Val259, Pro260 and Phe264. These changes to residue interactions are likely to destabilize the overall intra-protein residue communication network where the proteins' function could be implicated. Protein dynamics of the ATQ-bound mutant complexes showed that they assumed a different pose to the wild-type, resulting in diminished residue interactions in the mutant proteins. In summary, this study presents insights on the possible effect of the mutations on ATQ drug activity causing resistance and describes accurate MD simulations in the presence of the lipid bilayer prior to conducting inhibitory drug discovery for the PfCytb-iron sulphur protein (Cytb-ISP) complex.
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Affiliation(s)
| | | | | | | | - Özlem Tastan Bishop
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Makhanda 6140, South Africa; (L.C.-B.); (T.A.S.); (C.V.M.); (A.K.)
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6
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Massamba L, Madamet M, Benoit N, Chevalier A, Fonta I, Mondain V, Jeandel PY, Amalvict R, Delaunay P, Mosnier J, Marty P, Pomares C, Pradines B. Late clinical failure associated with cytochrome b codon 268 mutation during treatment of falciparum malaria with atovaquone-proguanil in traveller returning from Congo. Malar J 2020; 19:37. [PMID: 31964401 PMCID: PMC6975030 DOI: 10.1186/s12936-020-3126-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/16/2020] [Indexed: 12/17/2022] Open
Abstract
Background The drug combination atovaquone–proguanil, is recommended for treatment of uncomplicated falciparum malaria in France. Despite high efficacy, atovaquone–proguanil treatment failures have been reported. Resistance to cycloguanil, the active metabolite of proguanil, is conferred by multiple mutations in the Plasmodium falciparum dihydrofolate reductase (pfdhfr) and resistance to atovaquone by single mutation on codon 268 of the cytochrome b gene (pfcytb). Case presentation A 47-year-old female, native from Congo and resident in France, was admitted in hospital for uncomplicated falciparum malaria with parasitaemia of 0.5%, after travelling in Congo (Brazzaville and Pointe Noire). She was treated with atovaquone–proguanil (250 mg/100 mg) 4 tablets daily for 3 consecutive days. On day 5 after admission she was released home. However, many weeks after this episode, without having left France, she again experienced fever and intense weakness. On day 39 after the beginning of treatment, she consulted for fever, arthralgia, myalgia, photophobia, and blurred vision. She was hospitalized for uncomplicated falciparum malaria with a parasitaemia of 0.375% and treated effectively by piperaquine–artenimol (320 mg/40 mg) 3 tablets daily for 3 consecutive days. Resistance to atovaquone–proguanil was suspected. The Y268C mutation was detected in all of the isolates tested (D39, D42, D47). The genotyping of the pfdhfr gene showed a triple mutation (N51I, C59R, S108N) involved in cycloguanil resistance. Conclusion This is the first observation of a late clinical failure of atovaquone–proguanil treatment of P. falciparum uncomplicated malaria associated with pfcytb 268 mutation in a traveller returning from Congo. These data confirm that the Y268C mutation is associated with delayed recrudescence 4 weeks or more after initial treatment. Although atovaquone–proguanil treatment failures remain rare, an increased surveillance is required. It is essential to declare and publish all well-documented cases of treatment failures because it is the only way to evaluate the level of resistance to atovaquone.
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Affiliation(s)
- Laurencie Massamba
- Parasitologie Mycologie, Centre Hospitalo-Universitaire de Nice, Université de la Côte d'Azur, Nice, France
| | - Marylin Madamet
- Unité Parasitologie et entomologie, Département de Microbiologie et de maladies infectieuses, Institut de recherche biomédicale des armées, Marseille, France.,Aix Marseille Université, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre national de référence du Paludisme, Marseille, France
| | - Nicolas Benoit
- Unité Parasitologie et entomologie, Département de Microbiologie et de maladies infectieuses, Institut de recherche biomédicale des armées, Marseille, France.,Aix Marseille Université, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre national de référence du Paludisme, Marseille, France
| | - Alicia Chevalier
- Parasitologie Mycologie, Centre Hospitalo-Universitaire de Nice, Université de la Côte d'Azur, Nice, France
| | - Isabelle Fonta
- Unité Parasitologie et entomologie, Département de Microbiologie et de maladies infectieuses, Institut de recherche biomédicale des armées, Marseille, France.,Aix Marseille Université, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre national de référence du Paludisme, Marseille, France
| | - Véronique Mondain
- Infectiologie, Centre Hospitalo-Universitaire de Nice, Université de la Côte d'Azur, Nice, France
| | - Pierre-Yves Jeandel
- Service de Médecine Interne, Centre Hospitalier Universitaire de Nice, Nice, France
| | - Rémy Amalvict
- Unité Parasitologie et entomologie, Département de Microbiologie et de maladies infectieuses, Institut de recherche biomédicale des armées, Marseille, France.,Aix Marseille Université, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre national de référence du Paludisme, Marseille, France
| | - Pascal Delaunay
- Parasitologie Mycologie, Centre Hospitalo-Universitaire de Nice, Université de la Côte d'Azur, Nice, France.,MIVEGEC, UMR IRD 224-CNRS 5290-Université de Montpellier, Montpellier, France
| | - Joel Mosnier
- Unité Parasitologie et entomologie, Département de Microbiologie et de maladies infectieuses, Institut de recherche biomédicale des armées, Marseille, France.,Aix Marseille Université, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre national de référence du Paludisme, Marseille, France
| | - Pierre Marty
- Parasitologie Mycologie, Centre Hospitalo-Universitaire de Nice, Université de la Côte d'Azur, Nice, France.,INSERM, U1065, Centre Méditerranéen de Médecine Moléculaire, Faculté de Médecine, Virulence microbienne et signalisation inflammatoire, Nice, France
| | - Christelle Pomares
- Parasitologie Mycologie, Centre Hospitalo-Universitaire de Nice, Université de la Côte d'Azur, Nice, France.,INSERM, U1065, Centre Méditerranéen de Médecine Moléculaire, Faculté de Médecine, Virulence microbienne et signalisation inflammatoire, Nice, France
| | - Bruno Pradines
- Unité Parasitologie et entomologie, Département de Microbiologie et de maladies infectieuses, Institut de recherche biomédicale des armées, Marseille, France. .,Aix Marseille Université, IRD, SSA, AP-HM, VITROME, Marseille, France. .,IHU Méditerranée Infection, Marseille, France. .,Centre national de référence du Paludisme, Marseille, France.
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7
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Wojnarski M, Lon C, Vanachayangkul P, Gosi P, Sok S, Rachmat A, Harrison D, Berjohn CM, Spring M, Chaoratanakawee S, Ittiverakul M, Buathong N, Chann S, Wongarunkochakorn S, Waltmann A, Kuntawunginn W, Fukuda MM, Burkly H, Heang V, Heng TK, Kong N, Boonchan T, Chum B, Smith P, Vaughn A, Prom S, Lin J, Lek D, Saunders D. Atovaquone-Proguanil in Combination With Artesunate to Treat Multidrug-Resistant P. falciparum Malaria in Cambodia: An Open-Label Randomized Trial. Open Forum Infect Dis 2019; 6:ofz314. [PMID: 31660398 DOI: 10.1093/ofid/ofz314] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 06/28/2019] [Indexed: 12/16/2022] Open
Abstract
Background Recent artemisinin-combination therapy failures in Cambodia prompted a search for alternatives. Atovaquone-proguanil (AP), a safe, effective treatment for multidrug-resistant Plasmodium falciparum (P.f.), previously demonstrated additive effects in combination with artesunate (AS). Methods Patients with P.f. or mixed-species infection (n = 205) in Anlong Veng (AV; n = 157) and Kratie (KT; n = 48), Cambodia, were randomized open-label 1:1 to a fixed-dose 3-day AP regimen +/-3 days of co-administered artesunate (ASAP). Single low-dose primaquine (PQ, 15 mg) was given on day 1 to prevent gametocyte-mediated transmission. Results Polymerase chain reaction-adjusted adequate clinical and parasitological response at 42 days was 90% for AP (95% confidence interval [CI], 82%-95%) and 92% for ASAP (95% CI, 83%-96%; P = .73). The median parasite clearance time was 72 hours for ASAP in AV vs 56 hours in KT (P < .001) and was no different than AP alone. At 1 week postprimaquine, 7% of the ASAP group carried microscopic gametocytes vs 29% for AP alone (P = .0001). Nearly all P.f. isolates had C580Y K13 propeller artemisinin resistance mutations (AV 99%; KT 88%). Only 1 of 14 treatment failures carried the cytochrome bc1 (Pfcytb) atovaquone resistance mutation, which was not present at baseline. P.f. isolates remained atovaquone sensitive in vitro but cycloguanil resistant, with a triple P.f. dihydrofolate reductase mutation. Conclusions Atovaquone-proguanil remained marginally effective in Cambodia (≥90%) with minimal Pfcytb mutations observed. Treatment failures in the presence of ex vivo atovaquone sensitivity and adequate plasma levels may be attributable to cycloguanil and/or artemisinin resistance. Artesunate co-administration provided little additional blood-stage efficacy but reduced post-treatment gametocyte carriage in combination with AP beyond single low-dose primaquine.
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Affiliation(s)
- Mariusz Wojnarski
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Chanthap Lon
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | | | - Panita Gosi
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Somethy Sok
- Department of Health, Ministry of National Defense, Phnom Penh, Cambodia
| | - Agus Rachmat
- Naval Medical Research Unit-2, Phnom Penh, Cambodia
| | | | | | - Michele Spring
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.,Henry M. Jackson Foundation, Bethesda, Maryland
| | - Suwanna Chaoratanakawee
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.,Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mali Ittiverakul
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Nillawan Buathong
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Soklyda Chann
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | | | | | | | - Mark M Fukuda
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Hana Burkly
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Vireak Heang
- Naval Medical Research Unit-2, Phnom Penh, Cambodia
| | - Thay Keang Heng
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Nareth Kong
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Threechada Boonchan
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Bolin Chum
- Naval Medical Research Unit-2, Phnom Penh, Cambodia
| | - Philip Smith
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | | | - Satharath Prom
- Department of Health, Ministry of National Defense, Phnom Penh, Cambodia
| | - Jessica Lin
- Division of Infectious Diseases, University of North Carolina, Chapel Hill, North Carolina
| | - Dysoley Lek
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - David Saunders
- US Army Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.,US Army Medical Materiel Development Activity, Fort Detrick, Maryland
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8
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Staines HM, Burrow R, Teo BHY, Chis Ster I, Kremsner PG, Krishna S. Clinical implications of Plasmodium resistance to atovaquone/proguanil: a systematic review and meta-analysis. J Antimicrob Chemother 2019; 73:581-595. [PMID: 29237012 PMCID: PMC5890752 DOI: 10.1093/jac/dkx431] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 10/23/2017] [Indexed: 11/26/2022] Open
Abstract
Background Atovaquone/proguanil, registered as Malarone®, is a fixed-dose combination recommended for first-line treatment of uncomplicated Plasmodium falciparum malaria in non-endemic countries and its prevention in travellers. Mutations in the cytochrome bc1 complex are causally associated with atovaquone resistance. Methods This systematic review assesses the clinical efficacy of atovaquone/proguanil treatment of uncomplicated malaria and examines the extent to which codon 268 mutation in cytochrome b influences treatment failure and recrudescence based on published information. Results Data suggest that atovaquone/proguanil treatment efficacy is 89%–98% for P. falciparum malaria (from 27 studies including between 18 and 253 patients in each case) and 20%–26% for Plasmodium vivax malaria (from 1 study including 25 patients). The in vitro P. falciparum phenotype of atovaquone resistance is an IC50 value >28 nM. Case report analyses predict that recrudescence in a patient presenting with parasites carrying cytochrome b codon 268 mutation will occur on average at day 29 (95% CI: 22, 35), 19 (95% CI: 7, 30) days longer than if the mutation is absent. Conclusions Evidence suggests atovaquone/proguanil treatment for P. falciparum malaria is effective. Late treatment failure is likely to be associated with a codon 268 mutation in cytochrome b, though recent evidence from animal models suggests these mutations may not spread within the population. However, early treatment failure is likely to arise through alternative mechanisms, requiring further investigation.
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Affiliation(s)
- Henry M Staines
- Centre for Diagnostics and Antimicrobial Resistance, Institute for Infection & Immunity, St George's University of London, London, UK.,Institute for Infection & Immunity, St George's University of London, London, UK
| | - Rebekah Burrow
- Institute for Infection & Immunity, St George's University of London, London, UK
| | - Beatrix Huei-Yi Teo
- Institute for Infection & Immunity, St George's University of London, London, UK
| | - Irina Chis Ster
- Institute for Infection & Immunity, St George's University of London, London, UK
| | - Peter G Kremsner
- Institut für Tropenmedizin Universitätsklinikum Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Sanjeev Krishna
- Centre for Diagnostics and Antimicrobial Resistance, Institute for Infection & Immunity, St George's University of London, London, UK.,Institute for Infection & Immunity, St George's University of London, London, UK.,Institut für Tropenmedizin Universitätsklinikum Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,St George's University Hospitals NHS Foundation Trust, London, UK
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9
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Cook RL. Principal components of localization-delocalization matrices: new descriptors for modeling biological activities of organic compounds. Part I: mosquito insecticides and repellents. Struct Chem 2017. [DOI: 10.1007/s11224-017-0998-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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10
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Cui L, Mharakurwa S, Ndiaye D, Rathod PK, Rosenthal PJ. Antimalarial Drug Resistance: Literature Review and Activities and Findings of the ICEMR Network. Am J Trop Med Hyg 2015; 93:57-68. [PMID: 26259943 PMCID: PMC4574275 DOI: 10.4269/ajtmh.15-0007] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 04/27/2015] [Indexed: 11/07/2022] Open
Abstract
Antimalarial drugs are key tools for the control and elimination of malaria. Recent decreases in the global malaria burden are likely due, in part, to the deployment of artemisinin-based combination therapies. Therefore, the emergence and potential spread of artemisinin-resistant parasites in southeast Asia and changes in sensitivities to artemisinin partner drugs have raised concerns. In recognition of this urgent threat, the International Centers of Excellence for Malaria Research (ICEMRs) are closely monitoring antimalarial drug efficacy and studying the mechanisms underlying drug resistance. At multiple sentinel sites of the global ICEMR network, research activities include clinical studies to track the efficacies of antimalarial drugs, ex vivo/in vitro assays to measure drug susceptibilities of parasite isolates, and characterization of resistance-mediating parasite polymorphisms. Taken together, these efforts offer an increasingly comprehensive assessment of the efficacies of antimalarial therapies, and enable us to predict the emergence of drug resistance and to guide local antimalarial drug policies. Here we briefly review worldwide antimalarial drug resistance concerns, summarize research activities of the ICEMRs related to drug resistance, and assess the global impacts of the ICEMR programs.
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Affiliation(s)
- Liwang Cui
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
| | | | | | | | - Philip J. Rosenthal
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
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11
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Ingasia LA, Akala HM, Imbuga MO, Opot BH, Eyase FL, Johnson JD, Bulimo WD, Kamau E. Molecular characterization of the cytochrome b gene and in vitro atovaquone susceptibility of Plasmodium falciparum isolates from Kenya. Antimicrob Agents Chemother 2015; 59:1818-21. [PMID: 25583715 PMCID: PMC4325819 DOI: 10.1128/aac.03956-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 01/04/2015] [Indexed: 11/20/2022] Open
Abstract
The prevalence of a genetic polymorphism(s) at codon 268 in the cytochrome b gene, which is associated with failure of atovaquone-proguanil treatment, was analyzed in 227 Plasmodium falciparum parasites from western Kenya. The prevalence of the wild-type allele was 63%, and that of the Y268S (denoting a Y-to-S change at position 268) mutant allele was 2%. There were no pure Y268C or Y268N mutant alleles, only mixtures of a mutant allele(s) with the wild type. There was a correlation between parasite 50% inhibitory concentration (IC50) and parasite genetic polymorphism; mutant alleles had higher IC50s than the wild type.
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Affiliation(s)
- Luicer A Ingasia
- Department of Emerging Infectious Diseases-Global Emerging Infections Surveillance and Response System (DEID-GEIS) Program, U.S. Army Medical Research Unit-Kenya (USAMRU-K), Kenya Medical Research Institute (KEMRI)-Walter Reed Project, Kisumu, Kenya
| | - Hoseah M Akala
- Department of Emerging Infectious Diseases-Global Emerging Infections Surveillance and Response System (DEID-GEIS) Program, U.S. Army Medical Research Unit-Kenya (USAMRU-K), Kenya Medical Research Institute (KEMRI)-Walter Reed Project, Kisumu, Kenya
| | - Mabel O Imbuga
- Department of Biochemistry, College of Health Sciences, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Benjamin H Opot
- Department of Emerging Infectious Diseases-Global Emerging Infections Surveillance and Response System (DEID-GEIS) Program, U.S. Army Medical Research Unit-Kenya (USAMRU-K), Kenya Medical Research Institute (KEMRI)-Walter Reed Project, Kisumu, Kenya
| | - Fredrick L Eyase
- Department of Emerging Infectious Diseases-Global Emerging Infections Surveillance and Response System (DEID-GEIS) Program, U.S. Army Medical Research Unit-Kenya (USAMRU-K), Kenya Medical Research Institute (KEMRI)-Walter Reed Project, Kisumu, Kenya
| | - Jacob D Johnson
- Department of Emerging Infectious Diseases-Global Emerging Infections Surveillance and Response System (DEID-GEIS) Program, U.S. Army Medical Research Unit-Kenya (USAMRU-K), Kenya Medical Research Institute (KEMRI)-Walter Reed Project, Kisumu, Kenya
| | - Wallace D Bulimo
- Department of Emerging Infectious Diseases-Global Emerging Infections Surveillance and Response System (DEID-GEIS) Program, U.S. Army Medical Research Unit-Kenya (USAMRU-K), Kenya Medical Research Institute (KEMRI)-Walter Reed Project, Kisumu, Kenya
| | - Edwin Kamau
- Department of Emerging Infectious Diseases-Global Emerging Infections Surveillance and Response System (DEID-GEIS) Program, U.S. Army Medical Research Unit-Kenya (USAMRU-K), Kenya Medical Research Institute (KEMRI)-Walter Reed Project, Kisumu, Kenya
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12
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Plucinski MM, Huber CS, Akinyi S, Dalton W, Eschete M, Grady K, Silva-Flannery L, Mathison BA, Udhayakumar V, Arguin PM, Barnwell JW. Novel Mutation in Cytochrome B of Plasmodium falciparum in One of Two Atovaquone-Proguanil Treatment Failures in Travelers Returning From Same Site in Nigeria. Open Forum Infect Dis 2014; 1:ofu059. [PMID: 25734129 PMCID: PMC4281801 DOI: 10.1093/ofid/ofu059] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 07/01/2014] [Indexed: 11/14/2022] Open
Abstract
Background Atovaquone-proguanil (AP) is the most commonly used treatment for uncomplicated Plasmodium falciparum malaria in the United States. Apparent AP treatment failures were reported 7 months apart in 2 American travelers who stayed in the same compound for foreign workers in Rivers State, Nigeria. Methods We analyzed pretreatment (day 0) and day of failure samples from both travelers for mutations in the P falciparum cytochrome B (pfcytb) and dihydrofolate reductase (pfdhfr) genes associated with resistance to atovaquone and cycloguanil, the active metabolite of proguanil, respectively. We genotyped the parasites and sequenced their mitochondrial genomes. Results On day 0, both travelers had proguanil-resistant genotypes but atovaquone-sensitive cytb sequences. Day of failure samples exhibited mutations in cytb for both travelers. One traveler had the common Y268S mutation, whereas the other traveler had a previously unreported mutation, I258M. The travelers had unrelated parasite genotypes and different mitochondrial genomes. Conclusions Despite the infections likely having been contracted in the same site, there is no evidence that the cases were related. The mutations likely arose independently during the acute infection or treatment. Our results highlight the importance of genotyping parasites and sequencing the full cytb and dhfr genes in AP failures to rule out transmission of AP-resistant strains and identify novel mechanisms of AP resistance.
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Affiliation(s)
- Mateusz M Plucinski
- Division of Parasitic Diseases and Malaria, Center for Global Health ; Epidemic Intelligence Service , Centers for Disease Control and Prevention , Atlanta, Georgia
| | - Curtis S Huber
- Division of Parasitic Diseases and Malaria, Center for Global Health
| | - Sheila Akinyi
- Division of Parasitic Diseases and Malaria, Center for Global Health
| | | | - Mary Eschete
- Terrebonne General Medical Center, Houma, Louisiana
| | - Katharine Grady
- Division of Parasitic Diseases and Malaria, Center for Global Health
| | | | - Blaine A Mathison
- Division of Parasitic Diseases and Malaria, Center for Global Health
| | | | - Paul M Arguin
- Division of Parasitic Diseases and Malaria, Center for Global Health
| | - John W Barnwell
- Division of Parasitic Diseases and Malaria, Center for Global Health
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13
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Bottieau E, Vekemans M, Van Gompel A. Therapy of vector-borne protozoan infections in nonendemic settings. Expert Rev Anti Infect Ther 2014; 9:583-608. [DOI: 10.1586/eri.11.32] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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14
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Genetic and genomic approaches for the discovery of parasite genes involved in antimalarial drug resistance. Parasitology 2013; 140:1455-67. [PMID: 23931581 DOI: 10.1017/s0031182013000954] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The biggest threat to the war on malaria is the continued evolution of drug resistance by the parasite. Resistance to almost all currently available antimalarials now exists in Plasmodium falciparum which causes the most suffering among all human malaria parasites. Monitoring of antimalarial efficacy and the development and subsequent spread of resistance has become an important part in the treatment and control of malaria. With recent reports of reduced efficacy of artemisinin, the current recommended treatment for uncomplicated malaria, there is urgent need for better methods to recognize and monitor drug resistance for effective treatment. Molecular markers have become a welcome addition to complement the more laborious and costly in vitro and in vivo methods that have traditionally been used to monitor drug resistance. However, there are currently no molecular markers for resistance to some antimalarials. This review highlights the role of the various genetic and genomic approaches that have been used in identifying the molecular markers that underlie drug resistance in P. falciparum. These approaches include; candidate genes, genetic linkage and genome-wide association studies. We discuss the requirements and limitations of each approach and use various examples to illustrate their contributions in identifying genomic regions of the parasite associated with antimalarial drug responses.
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15
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Abstract
Malaria continues to affect public health and economic growth in many regions of the world. The number of infections continues to rise and is associated with increased mortality, despite basic science and public health efforts. Drug therapy remains the mainstay of treatment and prevention of this disease. Plasmodium has a complex life cycle involving an arthropod vector and distinct stages within the human host. Each parasite stage plays a unique role in transmission, disease, and latency. These different stages may vary in their response to the various antimalarial compounds. This article will review antimalarial therapies and drug resistance in the context of the parasites' biology.
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Affiliation(s)
- Johanna P Daily
- Brigham and Women's Hospital, Infectious Disease, 75 Francis Street, Boston, MA 02115, USA
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16
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Nixon GL, Moss DM, Shone AE, Lalloo DG, Fisher N, O'Neill PM, Ward SA, Biagini GA. Antimalarial pharmacology and therapeutics of atovaquone. J Antimicrob Chemother 2013; 68:977-85. [PMID: 23292347 PMCID: PMC4344550 DOI: 10.1093/jac/dks504] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Atovaquone is used as a fixed-dose combination with proguanil (Malarone) for treating children and adults with uncomplicated malaria or as chemoprophylaxis for preventing malaria in travellers. Indeed, in the USA, between 2009 and 2011, Malarone prescriptions accounted for 70% of all antimalarial pre-travel prescriptions. In 2013 the patent for Malarone will expire, potentially resulting in a wave of low-cost generics. Furthermore, the malaria scientific community has a number of antimalarial quinolones with a related pharmacophore to atovaquone at various stages of pre-clinical development. With this in mind, it is timely here to review the current knowledge of atovaquone, with the purpose of aiding the decision making of clinicians and drug developers involved in the future use of atovaquone generics or atovaquone derivatives.
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Affiliation(s)
- Gemma L Nixon
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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17
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Wurtz N, Pascual A, Marin-Jauffre A, Bouchiba H, Benoit N, Desbordes M, Martelloni M, Pommier de Santi V, Richa G, Taudon N, Pradines B, Briolant S. Early treatment failure during treatment of Plasmodium falciparum malaria with atovaquone-proguanil in the Republic of Ivory Coast. Malar J 2012; 11:146. [PMID: 22551095 PMCID: PMC3447648 DOI: 10.1186/1475-2875-11-146] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 05/02/2012] [Indexed: 11/29/2022] Open
Abstract
The increased spread of drug-resistant malaria highlights the need for alternative drugs for treatment and chemoprophylaxis. The combination of atovaquone‐proguanil (Malarone®) has shown high efficacy against Plasmodium falciparum with only mild side-effects. Treatment failures have been attributed to suboptimal dosages or to parasite resistance resulting from a point mutation in the cytochrome b gene. In this paper, a case of early treatment failure was reported in a patient treated with atovaquone-proguanil; this failure was not associated with a mutation in the parasite cytochrome b gene, with impaired drug bioavailability, or with re-infection.
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Affiliation(s)
- Nathalie Wurtz
- Unité de Parasitologie - Unité de Recherche pour les Maladies Infectieuses et Tropicales Emergentes - UMR 6236, Institut de Recherche Biomédicale des Armées, Marseille, France.
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18
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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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19
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Forestier E, Labe A, Raffenot D, Lecomte C, Rogeaux O. [Post-malaria neurological syndrome complicating a relapse of Plasmodium falciparum malaria after atovaquone-proguanil treatment]. Med Mal Infect 2010; 41:41-3. [PMID: 20800398 DOI: 10.1016/j.medmal.2010.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 06/01/2010] [Accepted: 07/20/2010] [Indexed: 10/19/2022]
Affiliation(s)
- E Forestier
- Service de maladies infectieuses, centre hospitalier, Chambéry cedex, France.
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20
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Batista R, de Jesus Silva Júnior A, de Oliveira AB. Plant-derived antimalarial agents: new leads and efficient phytomedicines. Part II. Non-alkaloidal natural products. Molecules 2009; 14:3037-72. [PMID: 19701144 PMCID: PMC6254980 DOI: 10.3390/molecules14083037] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 08/07/2009] [Accepted: 08/13/2009] [Indexed: 11/17/2022] Open
Abstract
Malaria is still the most destructive and dangerous parasitic infection in many tropical and subtropical countries. The burden of this disease is getting worse, mainly due to the increasing resistance of Plasmodium falciparum against the widely available antimalarial drugs. There is an urgent need for new, more affordable and accessible antimalarial agents possessing original modes of action. Natural products have played a dominant role in the discovery of leads for the development of drugs to treat human diseases, and this fact anticipates that new antimalarial leads may certainly emerge from tropical plant sources. This present review covers most of the recently-published non-alkaloidal natural compounds from plants with antiplasmodial and antimalarial properties, belonging to the classes of terpenes, limonoids, flavonoids, chromones, xanthones, anthraquinones, miscellaneous and related compounds, besides the majority of papers describing antiplasmodial crude extracts published in the last five years not reviewed before. In addition, some perspectives and remarks on the development of new drugs and phytomedicines for malaria are succinctly discussed.
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Affiliation(s)
- Ronan Batista
- Departamento de Estudos Básicos e Instrumentais, Universidade Estadual do Sudoeste da Bahia – UESB, BR 415, Km 03, s/nº, 45.700-000 Itapetinga, BA, Brazil; E-mail: (A.d.J.S.J.)
| | - Ademir de Jesus Silva Júnior
- Departamento de Estudos Básicos e Instrumentais, Universidade Estadual do Sudoeste da Bahia – UESB, BR 415, Km 03, s/nº, 45.700-000 Itapetinga, BA, Brazil; E-mail: (A.d.J.S.J.)
| | - Alaíde Braga de Oliveira
- Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil; E-mail: (A.B.d.O.)
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Sutherland CJ, Laundy M, Price N, Burke M, Fivelman QL, Pasvol G, Klein JL, Chiodini PL. Mutations in the Plasmodium falciparum cytochrome b gene are associated with delayed parasite recrudescence in malaria patients treated with atovaquone-proguanil. Malar J 2008; 7:240. [PMID: 19021900 PMCID: PMC2640403 DOI: 10.1186/1475-2875-7-240] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Accepted: 11/20/2008] [Indexed: 11/25/2022] Open
Abstract
Background Fixed-dose combination antimalarial drugs have played an increasingly important role in the treatment and chemoprophylaxis of falciparum malaria since the worldwide failure of monotherapy with chloroquine. Atovaquone-proguanil is one such combination drug used both for prophylaxis in travellers, and for treatment of acute malaria cases in European hospitals and clinics. Methods A series of eight atovaquone-proguanil treatment failures and two prophylaxis breakthroughs from four UK hospitals from 2004–2008 were analysed for evidence of mutations in the pfcyt-b gene, previously found to be associated with failure of the atovaquone component. Results Parasites carrying pfcyt-b mutations were found in five falciparum malaria patients with recrudescent parasitaemia occurring weeks after apparently successful treatment of a primary infection with atovaquone-proguanil. Four of these cases carried parasites with the Tyr268Cys mutation in pfcyt-b, previously reported in two French patients with malaria. In contrast, mutations in pfcyt-b were not found in three patients treated with atovaquone-proguanil who exhibited delayed clearance of the primary infection, nor in two returning travellers with malaria who had used the combination for prophylaxis. Using current and previously published data, mean time to recrudescence of parasites carrying pfcytb codon 268 mutations was estimated as 28.0 days after treatment (95% C.I. 23.0 – 33.0 days), whereas treatment failures without codon 268 mutations received rescue treatment an average of 4.71 days after initial AP treatment (95% C.I. 1.76 – 7.67 days). Conclusion Genetically-determined parasite resistance to atovaquone is associated with delayed recrudescence of resistant parasites three weeks or more after initial clearance of parasitaemia by atovaquone/proguanil therapy. The 268-Cys allele of pfcyt-b may have been overlooked in previous studies of atovaquone-proguanil treatment failure as it is not detected by current RFLP methods.
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Affiliation(s)
- Colin J Sutherland
- Department of Clinical Parasitology, Hospital for Tropical Diseases, Mortimer Market, Capper St, London, WC1E 6AU, UK.
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Durand R, Prendki V, Cailhol J, Hubert V, Ralaimazava P, Massias L, Bouchaud O, Le Bras J. Plasmodium falciparum malaria and atovaquone-proguanil treatment failure. Emerg Infect Dis 2008; 14:320-2. [PMID: 18258131 PMCID: PMC2600204 DOI: 10.3201/eid1402.070945] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We noticed overrepresentation of atovaquone-proguanil therapeutic failures among Plasmodium falciparum-infected travelers weighing >100 kg. We report here 1 of these cases, which was not due to resistant parasites or impaired drug bioavailability. The follow-up of such patients should be strengthened.
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Ekala MT, Khim N, Legrand E, Randrianarivelojosia M, Jambou R, Fandeur T, Menard D, Assi SB, Henry MC, Rogier C, Bouchier C, Mercereau-Puijalon O. Sequence analysis of Plasmodium falciparum cytochrome b in multiple geographic sites. Malar J 2007; 6:164. [PMID: 18086297 PMCID: PMC2228307 DOI: 10.1186/1475-2875-6-164] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Accepted: 12/17/2007] [Indexed: 11/29/2022] Open
Abstract
Background The antimalarial drug atovaquone specifically targets Plasmodium falciparum cytochrome b (Pfcytb), a mitochondrial gene with uniparental inheritance. Cases of resistance to atovaquone associated with mutant Pfcytb have been reported, justifying efforts to better document the natural polymorphism of this gene. To this end, a large molecular survey was conducted in several malaria endemic areas where atovaquone was not yet in regular use. Methods The polymorphism of the Pfcytb was analysed by direct sequencing of PCR products corresponding to the full length coding region. Sequence was generated for 671 isolates originating from three continents: Africa (Senegal, Ivory Coast, Central African Republic and Madagascar), Asia (Cambodia) and South America (French Guiana). Results Overall, 11 polymorphic sites were observed, of which eight were novel mutations. There was a large disparity in the geographic distribution of the mutants. All isolates from Senegal, Central African Republic and Madagascar displayed a Camp/3D7 wild type Pfcytb sequence, as did most samples originating from Cambodia and Ivory Coast. One synonymous (t759a at codon V253V) and two non-synonymous (t553g and a581g at codons F185V and H194R, respectively) singletons were detected in Ivory Coast. Likewise, two synonymous (a126t and c793t at codons -T42T and L265L, respectively) singletons were observed in Cambodia. In contrast, seven mutated sites, affecting seven codons and defining four mutant haplotypes were observed in French Guiana. The wild type allele was observed in only 14% of the French Guiana isolates. The synonymous c688t mutation at position L230L was highly prevalent; the most frequent allele was the c688t single mutant, observed in 84% of the isolates. The other alleles were singletons (a126t/a165c, a4g/a20t/a1024c and a20t/t341c/c688t corresponding to T42T/S55S, N2D/N71I/I342L, N71I/L114S/L230L, respectively" please replace with ' corresponding to T42T/S55S, N2D/N71I/I342L and N71I/L114S/L230L, respectively). The codon 268 polymorphisms associated with atovaquone resistance were not observed in the panel the isolates studied. Overall, the wild type PfCYTb protein isoform was highly predominant in all study areas, including French Guiana, suggesting stringent functional constraints. Conclusion These data along with previously identified Pfcytb field polymorphisms indicate a clustering of molecular signatures, suggesting different ancestral types in South America and other continents. The absence of mutations associated with most atovaquone-proguanil clinical failures indicates that the atovaquone-proguanil association is an interesting treatment option in the study areas.
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Affiliation(s)
- Marie-Thérèse Ekala
- Immunologie Moléculaire des Parasites, CNRS URA 2581, Institut Pasteur, 25 rue du Dr ROUX, 75724 Paris Cedex 15, Paris, France.
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Synergistic interaction between atovaquone and retinol in Plasmodium falciparum in vitro. Wien Klin Wochenschr 2007; 119:45-52. [DOI: 10.1007/s00508-007-0868-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Kessl JJ, Meshnick SR, Trumpower BL. Modeling the molecular basis of atovaquone resistance in parasites and pathogenic fungi. Trends Parasitol 2007; 23:494-501. [PMID: 17826334 DOI: 10.1016/j.pt.2007.08.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 06/27/2007] [Accepted: 08/23/2007] [Indexed: 10/22/2022]
Abstract
Atovaquone is a substituted hydroxynaphthoquinone that is used therapeutically for treating Plasmodium falciparum malaria, Pneumocystis jirovecii pneumonia and Toxoplasma gondii toxoplasmosis. It is thought to act on these organisms by inhibiting parasite and fungal respiration by binding to the cytochrome bc1 complex. The recent, growing failure of atovaquone treatment and increased mortality of patients with malaria or Pneumocystis pneumonia has been linked to the appearance of mutations in the cytochrome b gene. To better understand the molecular basis of drug resistance, we have developed the yeast and bovine bc1 complexes as surrogates to model the molecular interaction of atovaquone with human and resistant pathogen enzymes.
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Affiliation(s)
- Jacques J Kessl
- Center for Retrovirus Research, College of Pharmacy, Ohio State University, Columbus, OH 43210, USA
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Abstract
Despite intensive research extending back to the 1930s, when the first synthetic antimalarial drugs made their appearance, the repertoire of clinically licensed formulations remains very limited. Moreover, widespread and increasing resistance to these drugs contributes enormously to the difficulties in controlling malaria, posing considerable intellectual, technical and humanitarian challenges. A detailed understanding of the molecular mechanisms underlying resistance to these agents is emerging that should permit new drugs to be rationally developed and older ones to be engineered to regain their efficacy. This review summarizes recent progress in analysing the causes of resistance to the major antimalarial drugs and its spread.
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Affiliation(s)
- John E Hyde
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, UK.
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Legrand E, Demar M, Volney B, Ekala MT, Quinternet M, Bouchier C, Fandeur T, Rogier C, Carme B, Puijalon OM, Esterre P. First case of emergence of atovaquone resistance in Plasmodium falciparum during second-line atovaquone-proguanil treatment in South America. Antimicrob Agents Chemother 2007; 51:2280-1. [PMID: 17438062 PMCID: PMC1891413 DOI: 10.1128/aac.01532-06] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Abstract
Synthesis de novo, acquisition by salvage and interconversion of purines and pyrimidines represent the fundamental requirements for their eventual assembly into nucleic acids as nucleotides and the deployment of their derivatives in other biochemical pathways. A small number of drugs targeted to nucleotide metabolism, by virtue of their effect on folate biosynthesis and recycling, have been successfully used against apicomplexan parasites such as Plasmodium and Toxoplasma for many years, although resistance is now a major problem in the prevention and treatment of malaria. Many targets not involving folate metabolism have also been explored at the experimental level. However, the unravelling of the genome sequences of these eukaryotic unicellular organisms, together with increasingly sophisticated molecular analyses, opens up possibilities of introducing new drugs that could interfere with these processes. This review examines the status of established drugs of this type and the potential for further exploiting the vulnerability of apicomplexan human pathogens to inhibition of this key area of metabolism.
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Affiliation(s)
- John E Hyde
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester M1 7ND, UK.
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Molecular surveillance of mutations in the cytochrome b gene of Plasmodium falciparum in Gabon and Ethiopia. Malar J 2006; 5:112. [PMID: 17118179 PMCID: PMC1679811 DOI: 10.1186/1475-2875-5-112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Accepted: 11/21/2006] [Indexed: 11/10/2022] Open
Abstract
Background Atovaquone is part of the antimalarial drug combination atovaquone-proguanil (Malarone®) and inhibits the cytochrome bc1 complex of the electron transport chain in Plasmodium spp. Molecular modelling showed that amino acid mutations are clustered around a putative atovaquone-binding site resulting in a reduced binding affinity of atovaquone for plasmodial cytochrome b, thus resulting in drug resistance. Methods The prevalence of cytochrome b point mutations possibly conferring atovaquone resistance in Plasmodium falciparum isolates in atovaquone treatment-naïve patient cohorts from Lambaréné, Gabon and from South Western Ethiopia was assessed. Results Four/40 (10%) mutant types (four different single polymorphisms, one leading to an amino acid change from M to I in a single case) in Gabonese isolates, but all 141/141 isolates were wild type in Ethiopia were found. Conclusion In the absence of drug pressure, spontaneous and possibly resistance-conferring mutations are rare.
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Berry A, Senescau A, Lelièvre J, Benoit-Vical F, Fabre R, Marchou B, Magnaval JF. Prevalence of Plasmodium falciparum cytochrome b gene mutations in isolates imported from Africa, and implications for atovaquone resistance. Trans R Soc Trop Med Hyg 2006; 100:986-8. [PMID: 16690094 DOI: 10.1016/j.trstmh.2006.02.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Revised: 02/23/2006] [Accepted: 02/24/2006] [Indexed: 10/24/2022] Open
Abstract
The atovaquone resistance of malaria parasites correlates with mutations in the cytochrome b gene. We sequenced the Plasmodium falciparum cytochrome b gene of 135 African isolates. Our data showed a high mutation rate (8.9%); however, the risk of emergence spreading of atovaquone-resistant P. falciparum strains could be limited.
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Affiliation(s)
- A Berry
- Department of Parasitology, Rangueil University Hospital, 31059 Toulouse 9, France.
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Lütgendorf C, Rojanawatsirivet C, Wernsdorfer G, Sirichaisinthop J, Kollaritsch H, Wernsdorfer WH. Pharmacodynamic interaction between atovaquone and other antimalarial compounds against Plasmodium falciparum in vitro. Wien Klin Wochenschr 2006; 118:70-6. [PMID: 17131244 DOI: 10.1007/s00508-006-0685-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Atovaquone, a 2-hydroxy-1,4-naphthoquinone, was first introduced as a drug against opportunistic infections in immuno-compromised patients. Early clinical-parasitological experiences in the treatment of malaria were disappointing due to highly variable and poor absorption, a phenomenon typical for naphthoquinones. Proguanil was found to potentiate the activity of atovaquone and the combination of the two drugs was introduced as an antimalarial drug with blood schizontocidal and causal prophylactic activity. It is now widely used in therapy and prophylaxis. Despite the enhanced activity, the combination does not always overcome the problem of poor absorption of atovaquone, especially in the presence of gastro-intestinal disorders. Therefore, further combination with a fast-acting blood schizontocide, e.g. one of the artemisinins, could accelerate clinical improvement and normalization of absorption. The interaction between artemisinin and atovaquone and that of artemisinin and atovaquone + proguanil has been investigated in 37 fresh isolates of Plasmodium falciparum from northwestern Thailand, an area with high prevalence of multi-drug resistance. Interaction between atovaquone and artemisinin was synergistic above the EC(30), with mean SigmaFIC (Berenbaum) values of 0.9679 at the EC(50), 0.4014 at the EC(90) and 0.2214 at the EC(99). Synergism was more pronounced with the triple combination, i.e. atovaquone + proguanil and artemisinin, starting at the EC(10) level. The mean SigmaFIC values were 0.7626 at the EC(50), 0.2939 at the EC(90), and 0.1527 at the EC(99). The strong synergism at the therapeutically relevant effective concentrations suggests that the therapeutic efficacy of atovaquone-proguanil can be considerably enhanced by the additional administration of a suitable artemisinin derivative, e.g. artesunate.
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Affiliation(s)
- Carola Lütgendorf
- Institute of Specific Prophylaxis and Tropical Medicine, Centre for Physiology and Pathophysiology, Medical University of Vienna, Vienna, Austria
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Koch S, Göbels K, Richter J, Oette M, Häussinger D. Cerebral malaria in spite of peripheral parasite clearance in a patient treated with atovaquone/proguanil. Parasitol Res 2006; 100:747-8. [PMID: 17004096 DOI: 10.1007/s00436-006-0317-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Accepted: 08/15/2006] [Indexed: 10/24/2022]
Abstract
Cerebral malaria, the most frequent complication of falciparum malaria, is usually predicted by an increased count of asexual parasites in peripheral blood. We report a case of a female returnee from Ghana who developed cerebral malaria in spite of parasite clearance in peripheral blood after therapy with atovaquone/proguanil.
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Affiliation(s)
- Stefanie Koch
- Clinics for Gastroenterology, Hepatology and Infectious Diseases, University Hospital Düsseldorf, Heinrich Heine University, Moorenstrasse 5, 40225, Düsseldorf, Germany
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Winter RW, Kelly JX, Smilkstein MJ, Dodean R, Bagby GC, Rathbun RK, Levin JI, Hinrichs D, Riscoe MK. Evaluation and lead optimization of anti-malarial acridones. Exp Parasitol 2006; 114:47-56. [PMID: 16828746 DOI: 10.1016/j.exppara.2006.03.014] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2005] [Revised: 03/27/2006] [Accepted: 03/28/2006] [Indexed: 02/06/2023]
Abstract
With 2-methoxy-6-chloroacridone as a lead compound, we synthesized and tested acridone derivatives to develop a better understanding of the anti-malarial structure-activity relationships. Over 30 acridone derivatives were synthesized. The most potent compounds contained extended alkyl chains terminated by trifluoromethyl groups and located at the 3-position of the tricyclic system. Acridones optimized in the length of the side chain and the nature of the terminal fluorinated moiety exhibited in vitro anti-malarial IC(50) values in the low nanomolar and picomolar range and were without cytotoxic effects on the proliferation and differentiation of human bone marrow progenitors or mitogen-activated murine lymphocytes at concentrations up to 100,000-fold higher. Based on a structural similarity to known anti-malarial agents it is proposed that the haloalkoxyacridones exert their anti-malarial effects through inhibition of the Plasmodium cytochrome bc(1) complex. Haloalkoxyacridones represent an extraordinarily potent novel class of chemical compounds with the potential for development as therapeutic agents to treat or prevent malaria in humans.
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Affiliation(s)
- Rolf W Winter
- Medical Research Service, RD-33, VA Medical Center, 3710 SW U.S. Veterans Hospital Road, Portland, OR 97239, USA
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Hitani A, Nakamura T, Ohtomo H, Nawa Y, Kimura M. Efficacy and safety of atovaquone-proguanil compared with mefloquine in the treatment of nonimmune patients with uncomplicated P. falciparum malaria in Japan. J Infect Chemother 2006; 12:277-82. [PMID: 17109092 DOI: 10.1007/s10156-006-0465-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Accepted: 07/13/2006] [Indexed: 11/28/2022]
Abstract
Malaria treatment is becoming increasingly difficult due to the widespread drug resistance of Plasmodium falciparum. In Japan, only three antimalarials are approved for treatment: oral quinine, sulfadoxine-pyrimethamine, and mefloquine. Recently, however, the Research Group on Chemotherapy of Tropical Diseases introduced atovaquone-proguanil for treating drug-resistant P. falciparum malaria. This research group had also introduced mefloquine before it was licensed nationally. Using data obtained from the research group, we analyzed the efficacy and safety of atovaquone-proguanil, as compared with mefloquine, in nonimmune patients with uncomplicated P. falciparum malaria. Cures were attained in all (100%) of 20 atovaquone-proguanil-treated and 49 (98%) of 50 mefloquine-treated adults. The mean fever clearance time (FCT) and parasite clearance time (PCT) appeared to be longer in the atovaquone-proguanil group than in the mefloquine group, but the differences were not statistically significant. Three (15%) of the 20 atovaquone-proguanil-treated adults had adverse events (AEs), all of which were transient elevations of liver enzymes, while 19 (38%) of the 50 mefloquine-treated adults had AEs, including dizziness in 8 (16%) and nausea/vomiting in 7 (14%). All 3 children treated with atovaquone-proguanil were cured without developing AEs. Despite the limitations of this study in not being a formal clinical trial, atovaquone-proguanil seemed to be at least equal to, or even better than, mefloquine for the treatment of uncomplicated P. falciparum malaria in nonimmune patients, including children. Its marketing in Japan could be beneficial in offering an alternative therapeutic option. However, vigilance should be maintained on the possible occurrence of rare but severe AEs, and also of the possible spread of drug resistance.
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Affiliation(s)
- Akihiro Hitani
- Healthcheck, Health Care Center, Medical Institute Zenjinkai, Yokohama, Japan
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35
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Hyde JE. Drug-resistant malaria. Trends Parasitol 2005; 21:494-8. [PMID: 16140578 PMCID: PMC2722032 DOI: 10.1016/j.pt.2005.08.020] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 08/08/2005] [Accepted: 08/18/2005] [Indexed: 11/26/2022]
Abstract
In the past 21 years, a modest increase in the range of antimalarial drugs approved for clinical use has been complemented by a more impressive expansion in the analysis and understanding of the molecular mechanisms underlying resistance to these agents. Such resistance is a major factor in the increasing difficulty in controlling malaria, and important developments during this period are recounted here.
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Affiliation(s)
- John E Hyde
- Faculty of Life Sciences, University of Manchester, Jackson's Mill, PO Box 88, Manchester M60 1QD, UK.
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Davis TME, Karunajeewa HA, Ilett KF. Artemisinin‐based combination therapies for uncomplicated malaria. Med J Aust 2005; 182:181-5. [PMID: 15720175 DOI: 10.5694/j.1326-5377.2005.tb06650.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Accepted: 12/24/2004] [Indexed: 11/17/2022]
Abstract
There has been a relentless increase in resistance of malaria parasites to conventional antimalarial drugs, including chloroquine, sulfadoxine-pyrimethamine and mefloquine. In response to this situation, short-course artemisinin-based combination therapies (ACTs) have been developed. The World Health Organization has endorsed ACT as first-line treatment where the potentially life-threatening parasite Plasmodium falciparum is the predominant infecting species. ACTs combine the rapid schizontocidal activity of an artemisinin derivative (artesunate, artemether or dihydroartemisinin) with a longer-half-life partner drug. Although the use of chloroquine and sulfadoxine-pyrimethamine as partners in ACT improves their efficacy, this may only have value as a short-term measure in patients with a degree of immunity to malaria. Alternative currently available partner drugs include mefloquine, lumefantrine and piperaquine. Artesunate-mefloquine is highly effective but is expensive and side effects (mainly neurotoxicity) can be problematic. Artemether-lumefantrine, the only ACT available in Australia, appears less effective than artesunate-mefloquine and needs to be administered with food to ensure adequate bioavailability. Dihydroartemisinin-piperaquine is highly effective, well tolerated and relatively inexpensive. The goal of potent, safe, easy-to-administer and inexpensive ACTs may see trioxolanes in place of artemisinin derivatives, as well as novel partner drugs such as pyronaridine or naphthoquine, in the future.
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Affiliation(s)
- Timothy M E Davis
- Medicine Unit, School of Medicine and Pharmacology, Fremantle Hospital, University of Western Australia, Fremantle, WA.
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