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Nguyen W, Dans MG, Currie I, Awalt JK, Bailey BL, Lumb C, Ngo A, Favuzza P, Palandri J, Ramesh S, Penington J, Jarman KE, Mukherjee P, Chakraborty A, Maier AG, van Dooren GG, Papenfuss T, Wittlin S, Churchyard A, Baum J, Winzeler EA, Baud D, Brand S, Jackson PF, Cowman AF, Sleebs BE. 7- N-Substituted-3-oxadiazole Quinolones with Potent Antimalarial Activity Target the Cytochrome bc1 Complex. ACS Infect Dis 2023; 9:668-691. [PMID: 36853190 PMCID: PMC10012268 DOI: 10.1021/acsinfecdis.2c00607] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
The development of new antimalarials is required because of the threat of resistance to current antimalarial therapies. To discover new antimalarial chemotypes, we screened the Janssen Jumpstarter library against the P. falciparum asexual parasite and identified the 7-N-substituted-3-oxadiazole quinolone hit class. We established the structure-activity relationship and optimized the antimalarial potency. The optimized analog WJM228 (17) showed robust metabolic stability in vitro, although the aqueous solubility was limited. Forward genetic resistance studies uncovered that WJM228 targets the Qo site of cytochrome b (cyt b), an important component of the mitochondrial electron transport chain (ETC) that is essential for pyrimidine biosynthesis and an established antimalarial target. Profiling against drug-resistant parasites confirmed that WJM228 confers resistance to the Qo site but not Qi site mutations, and in a biosensor assay, it was shown to impact the ETC via inhibition of cyt b. Consistent with other cyt b targeted antimalarials, WJM228 prevented pre-erythrocytic parasite and male gamete development and reduced asexual parasitemia in a P. berghei mouse model of malaria. Correcting the limited aqueous solubility and the high susceptibility to cyt b Qo site resistant parasites found in the clinic will be major obstacles in the future development of the 3-oxadiazole quinolone antimalarial class.
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Affiliation(s)
- William Nguyen
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Madeline G Dans
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Iain Currie
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Jon Kyle Awalt
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Brodie L Bailey
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Chris Lumb
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia
| | - Anna Ngo
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia
| | - Paola Favuzza
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Josephine Palandri
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Saishyam Ramesh
- Research School of Biology, The Australian National University, Canberra 2600, Australia
| | - Jocelyn Penington
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Kate E Jarman
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | | | | | - Alexander G Maier
- Research School of Biology, The Australian National University, Canberra 2600, Australia
| | - Giel G van Dooren
- Research School of Biology, The Australian National University, Canberra 2600, Australia
| | - Tony Papenfuss
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Sergio Wittlin
- Swiss Tropical and Public Health Institute, Kreuzstrasse 2, 4123 Allschwil, Switzerland.,University of Basel, 4003 Basel, Switzerland
| | - Alisje Churchyard
- Department of Life Sciences, Imperial College London, South Kensington, SW7 2AZ U.K
| | - Jake Baum
- Department of Life Sciences, Imperial College London, South Kensington, SW7 2AZ U.K.,School of Biomedical Sciences, University of New South Wales, Sydney 2031, Australia
| | - Elizabeth A Winzeler
- School of Medicine, University of California San Diego, 9500 Gilman Drive 0760, La Jolla, California 92093, United States
| | - Delphine Baud
- Medicines for Malaria Venture, Geneva 1215, Switzerland
| | - Stephen Brand
- Medicines for Malaria Venture, Geneva 1215, Switzerland
| | - Paul F Jackson
- Global Public Health, Janssen R&D LLC, La Jolla, California 92121, United States
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
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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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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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Selection of Plasmodium falciparum cytochrome B mutants by putative PfNDH2 inhibitors. Proc Natl Acad Sci U S A 2018; 115:6285-6290. [PMID: 29844160 DOI: 10.1073/pnas.1804492115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Malaria control is threatened by a limited pipeline of effective pharmaceuticals against drug-resistant strains of Plasmodium falciparum Components of the mitochondrial electron transport chain (ETC) are attractive targets for drug development, owing to exploitable differences between the parasite and human ETC. Disruption of ETC function interferes with metabolic processes including de novo pyrimidine synthesis, essential for nucleic acid replication. We investigated the effects of ETC inhibitor selection on two distinct P. falciparum clones, Dd2 and 106/1. Compounds CK-2-68 and RYL-552, substituted quinolones reported to block P. falciparum NADH dehydrogenase 2 (PfNDH2; a type II NADH:quinone oxidoreductase), unexpectedly selected mutations at the quinol oxidation (Qo) pocket of P. falciparum cytochrome B (PfCytB). Selection experiments with atovaquone (ATQ) on 106/1 parasites yielded highly resistant PfCytB Y268S mutants seen in clinical infections that fail ATQ-proguanil treatment. In contrast, ATQ pressure on Dd2 yielded moderately resistant parasites carrying a PfCytB M133I or K272R mutation. Strikingly, all ATQ-selected mutants demonstrated little change or slight increase of sensitivity to CK-2-68 or RYL-552. Molecular docking studies demonstrated binding of all three ETC inhibitors to the Qo pocket of PfCytB, where Y268 forms strong van der Waals interactions with the hydroxynaphthoquinone ring of ATQ but not the quinolone ring of CK-2-68 or RYL-552. Our results suggest that combinations of suitable ETC inhibitors may be able to subvert or delay the development of P. falciparum drug resistance.
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5
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Pagès F, Houze S, Kurtkowiak B, Balleydier E, Chieze F, Filleul L. Status of imported malaria on Réunion Island in 2016. Malar J 2018; 17:210. [PMID: 29793505 PMCID: PMC5968708 DOI: 10.1186/s12936-018-2345-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 05/07/2018] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Autochthonous malaria has been eliminated from Réunion in 1979. To prevent secondary transmission and re-emergence of autochthonous malaria, permanent epidemiologic and entomological surveillance and vector control measures are conducted around imported malaria cases. Results of local malaria surveillance (clinical data and results of epidemiological and entomological investigations around cases) were collected for 2013-2016 and were analysed according to historical data and to the exchanges with malaria-affected areas (estimated by airport data). RESULTS Form 2013 to 2016, 95 imported malaria cases have been detected in Reunion Island: 42% of cases occurred in the area of repartition of Anopheles arabiensis, but Anopheles mosquitoes were present only around seven cases including one gametocyte carrier. No autochthonous or introduced case has occurred during this period. The lack of chemoprophylaxis or poor adherence was found in the majority (96%) of malaria cases between 2013 and 2016, regardless of trip type. Affinity tourism in Madagascar and Comoros was the cause of 65% of imported malaria cases. DISCUSSION The incidence of imported malaria and the incidence rate per 100,000 travellers has continuously decreased since 2001. Now with the drastic decrease of malaria transmission in the Comoros archipelago, most of imported malaria cases in Reunion Island have been contaminated in Madagascar. Immigrants regularly resident in Reunion Island, which travel to malaria endemic countries (mainly Madagascar) to visit their friends and relatives (VFRs) represent a high-risk group of contracting malaria. VFRs, low adherence to pre-travel recommendations, in particular, the compliance on the use of chemoprophylaxis are the main drivers of imported malaria in Reunion Island. Furthermore as previously described, some general practitioners in Reunion Island are always not sufficiently aware of the official recommendations for prescriptions of prophylactic treatments. CONCLUSION Social mobilization targeted on the Malagasy community in Reunion Island could help to decrease the burden of imported malaria in Reunion Island. Because of the low number of gametocyte carriers and the absence of an Anopheles mosquito population when most malaria cases were imported those last 4 years, the risk of the appearance of introduced malaria cases and indigenous malaria cases appears low in Reunion Island.
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Affiliation(s)
- Frédéric Pagès
- Santé Publique France, Cire Océan Indien, 2, bis avenue Georges Brassens-CS 61002, 97713, Saint-Denis Cedex 9, Saint-Denis, Réunion, France.
| | - Sandrine Houze
- CNR Paludisme-Laboratoire de Parasitologie, APHP, Hôpital Bichat, Paris, France.,UMR 216, Merit, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | - Brian Kurtkowiak
- Vector Control Department, Agence régionale de santé Océan Indien, Paris, Saint-Denis, Réunion, France
| | - Elsa Balleydier
- Santé Publique France, Cire Océan Indien, 2, bis avenue Georges Brassens-CS 61002, 97713, Saint-Denis Cedex 9, Saint-Denis, Réunion, France
| | - François Chieze
- Health Monitoring Department, Agence régionale de santé Océan Indien, Paris, Saint-Denis, Réunion, France
| | - Laurent Filleul
- Santé Publique France, Cire Océan Indien, 2, bis avenue Georges Brassens-CS 61002, 97713, Saint-Denis Cedex 9, Saint-Denis, Réunion, France
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Menoctone Resistance in Malaria Parasites Is Conferred by M133I Mutations in Cytochrome b That Are Transmissible through Mosquitoes. Antimicrob Agents Chemother 2017; 61:AAC.00689-17. [PMID: 28584157 DOI: 10.1128/aac.00689-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 05/29/2017] [Indexed: 11/20/2022] Open
Abstract
Malaria-related mortality has slowly decreased over the past decade; however, eradication of malaria requires the development of new antimalarial chemotherapies that target liver stages of the parasite and combat the emergence of drug resistance. The diminishing arsenal of anti-liver-stage compounds sparked our interest in reviving the old and previously abandoned compound menoctone. In support of these studies, we developed a new convergent synthesis method that was facile, required fewer steps, produced better yields, and utilized less expensive reagents than the previously published method. Menoctone proved to be highly potent against liver stages of Plasmodium berghei (50 percent inhibitory concentration [IC50] = 0.41 nM) and erythrocytic stages of Plasmodium falciparum (113 nM). We selected for resistance to menoctone and found M133I mutations in cytochrome b of both P. falciparum and P. berghei The same mutation has been observed previously in atovaquone resistance, and we confirmed cross-resistance between menoctone and atovaquone in vitro (for P. falciparum) and in vivo (for P. berghei). Finally, we assessed the transmission potential of menoctone-resistant P. berghei and found that the M133I mutant parasites were readily transmitted from mouse to mosquitoes and back to mice. In each step, the M133I mutation in cytochrome b, inducing menoctone resistance, was confirmed. In summary, this study is the first to show the mechanism of resistance to menoctone and that menoctone and atovaquone resistance is transmissible through mosquitoes.
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7
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Schoener ER, Hunter S, Howe L. Development of a rapid HRM qPCR for the diagnosis of the four most prevalent Plasmodium lineages in New Zealand. Parasitol Res 2017; 116:1831-1841. [PMID: 28497225 DOI: 10.1007/s00436-017-5452-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 04/20/2017] [Indexed: 11/28/2022]
Abstract
Although wildlife rehabilitation and translocations are important tools in wildlife conservation in New Zealand, disease screening of birds has not been standardized. Additionally, the results of the screening programmes are often difficult to interpret due to missing disease data in resident or translocating avian populations. Molecular methods have become the most widespread method for diagnosing avian malaria (Plasmodium spp.) infections. However, these methods can be time-consuming, expensive and are less specific in diagnosing mixed infections. Thus, this study developed a new real-time PCR (qPCR) method that was able to detect and specifically identify infections of the three most common lineages of avian malaria in New Zealand (Plasmodium (Novyella) sp. SYAT05, Plasmodium elongatum GRW6 and Plasmodium spp. LINN1) as well as a less common, pathogenic Plasmodium relictum GRW4 lineage. The assay was also able to discern combinations of these parasites in the same sample and had a detection limit of five parasites per microlitre. Due to concerns relating to the presence of the potentially highly pathogenic P. relictum GRW4 lineage in avian populations, an additional confirmatory high resolution (HRM) qPCR was developed to distinguish between commonly identified P. elongatum GRW6 from P. relictum GRW4. The new qPCR assays were tested using tissue samples containing Plasmodium schizonts from three naturally infected dead birds resulting in the identified infection of P. elongatum GRW6. Thus, these rapid qPCR assays have shown to be cost-effective and rapid screening tools for the detection of Plasmodium infection in New Zealand native birds.
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Affiliation(s)
- E R Schoener
- Institute of Agriculture and Environment (IAE), Ecology, Massey University, Palmerston North, New Zealand
| | - S Hunter
- Institute of Veterinary, Animal and Biomedical Sciences (IVABS), Massey University, Palmerston North, New Zealand
| | - L Howe
- Institute of Veterinary, Animal and Biomedical Sciences (IVABS), Massey University, Palmerston North, New Zealand.
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8
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Brogi S, Giovani S, Brindisi M, Gemma S, Novellino E, Campiani G, Blackman MJ, Butini S. In silico study of subtilisin-like protease 1 (SUB1) from different Plasmodium species in complex with peptidyl-difluorostatones and characterization of potent pan-SUB1 inhibitors. J Mol Graph Model 2016; 64:121-130. [PMID: 26826801 PMCID: PMC5276822 DOI: 10.1016/j.jmgm.2016.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/04/2015] [Accepted: 01/16/2016] [Indexed: 11/23/2022]
Abstract
Homology models of four SUB1 orthologues from P. falciparum species were produced. We analyzed the binding mode of our previous difluorostatone inhibitors to six SUB1. In vitro activity of our difluorostatone-based inhibitors was correctly predicted. We derived a structure-based pan-SUB1 pharmacophore, and validated it in silico. We confirmed that development of pan-SUB1 inhibitors is a feasible task.
Plasmodium falciparum subtilisin-like protease 1 (SUB1) is a novel target for the development of innovative antimalarials. We recently described the first potent difluorostatone-based inhibitors of the enzyme ((4S)-(N-((N-acetyl-l-lysyl)-l-isoleucyl-l-threonyl-l-alanyl)-2,2-difluoro-3-oxo-4-aminopentanoyl)glycine (1) and (4S)-(N-((N-acetyl-l-isoleucyl)-l-threonyl-l-alanylamino)-2,2-difluoro-3-oxo-4-aminopentanoyl)glycine (2)). As a continuation of our efforts towards the definition of the molecular determinants of enzyme-inhibitor interaction, we herein propose the first comprehensive computational investigation of the SUB1 catalytic core from six different Plasmodium species, using homology modeling and molecular docking approaches. Investigation of the differences in the binding sites as well as the interactions of our inhibitors 1,2 with all SUB1 orthologues, allowed us to highlight the structurally relevant regions of the enzyme that could be targeted for developing pan-SUB1 inhibitors. According to our in silico predictions, compounds 1,2 have been demonstrated to be potent inhibitors of SUB1 from all three major clinically relevant Plasmodium species (P. falciparum, P. vivax, and P. knowlesi). We next derived multiple structure-based pharmacophore models that were combined in an inclusive pan-SUB1 pharmacophore (SUB1-PHA). This latter was validated by applying in silico methods, showing that it may be useful for the future development of potent antimalarial agents.
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Affiliation(s)
- Simone Brogi
- European Research Centre for Drug Discovery and Development (NatSynDrugs), University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Centro Interuniversitario di Ricerche sulla Malaria (CIRM), University of Perugia, Perugia, Italy
| | - Simone Giovani
- European Research Centre for Drug Discovery and Development (NatSynDrugs), University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Centro Interuniversitario di Ricerche sulla Malaria (CIRM), University of Perugia, Perugia, Italy
| | - Margherita Brindisi
- European Research Centre for Drug Discovery and Development (NatSynDrugs), University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Centro Interuniversitario di Ricerche sulla Malaria (CIRM), University of Perugia, Perugia, Italy
| | - Sandra Gemma
- European Research Centre for Drug Discovery and Development (NatSynDrugs), University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Centro Interuniversitario di Ricerche sulla Malaria (CIRM), University of Perugia, Perugia, Italy.
| | - Ettore Novellino
- European Research Centre for Drug Discovery and Development (NatSynDrugs), University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Dipartimento di Farmacia, University of Naples Federico II, Via D. Montesano 49, 80131, Naples, Italy
| | - Giuseppe Campiani
- European Research Centre for Drug Discovery and Development (NatSynDrugs), University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Centro Interuniversitario di Ricerche sulla Malaria (CIRM), University of Perugia, Perugia, Italy.
| | - Michael J Blackman
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
| | - Stefania Butini
- European Research Centre for Drug Discovery and Development (NatSynDrugs), University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, via Aldo Moro 2, 53100, Siena, Italy; Centro Interuniversitario di Ricerche sulla Malaria (CIRM), University of Perugia, Perugia, Italy
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9
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Atovaquone-Proguanil Remains a Potential Stopgap Therapy for Multidrug-Resistant Plasmodium falciparum in Areas along the Thai-Cambodian Border. Antimicrob Agents Chemother 2015; 60:1896-8. [PMID: 26711753 DOI: 10.1128/aac.02302-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 12/08/2015] [Indexed: 12/27/2022] Open
Abstract
Our recent report of dihydroartemisinin-piperaquine failure to treat Plasmodium falciparum infections in Cambodia adds new urgency to the search for alternative treatments. Despite dihydroartemisinin-piperaquine failure, and higher piperaquine 50% inhibitory concentrations (IC50s) following reanalysis than those previously reported, P. falciparum remained sensitive to atovaquone (ATQ) in vitro. There were no point mutations in the P. falciparum cytochrome b ATQ resistance gene. Mefloquine, artemisinin, chloroquine, and quinine IC50s remained comparable to those from other recent reports. Atovaquone-proguanil may be a useful stopgap but remains susceptible to developing resistance when used as blood-stage therapy.
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10
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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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11
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Tahar R, Almelli T, Debue C, Foumane Ngane V, Djaman Allico J, Whegang Youdom S, Basco LK. Randomized trial of artesunate-amodiaquine, atovaquone-proguanil, and artesunate-atovaquone-proguanil for the treatment of uncomplicated falciparum malaria in children. J Infect Dis 2014; 210:1962-71. [PMID: 24943722 DOI: 10.1093/infdis/jiu341] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Artemisinin-based combination therapies (ACTs) are recommended for the treatment of acute uncomplicated falciparum malaria in many malaria-endemic countries. Despite the emergence of artemisinin resistance, few alternative non-ACTs, including atovaquone-proguanil, are currently available. METHODS Plasmodium falciparum-infected Cameroonian children ≤5 years old (n = 338) were randomly assigned to artesunate-amodiaquine, atovaquone-proguanil, or artesunate-atovaquone-proguanil treatment groups and followed for 28 days, according to the standard World Health Organization protocol. In vitro response to atovaquone and cytochrome b sequence of clinical isolates were determined. RESULTS Eight late failures and 16 failures (8 late and 8 early failures) were observed after artesunate-amodiaquine and atovaquone-proguanil therapies, respectively. Most late failures were due to reinfections. Artesunate-atovaquone-proguanil was not associated with any failure. After correction by genotyping, per-protocol analysis showed no difference in the efficacy of 3 drugs. However, the proportion of atovaquone-proguanil-treated patients with positive smears on day 3 was much higher (36.0%; P < .05) than that of the artesunate-amodiaquine (2.9%) and artesunate-atovaquone-proguanil (1.0%) groups. In vitro response and cytochrome b sequence did not indicate atovaquone resistance. CONCLUSIONS Atovaquone-proguanil was characterized by a slow blood schizontocidal action and resulted in early treatment failure in a few patients. Artesunate-atovaquone-proguanil was a highly effective alternative treatment. CLINICAL TRIALS REGISTRATION UMIN000003813.
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Affiliation(s)
- Rachida Tahar
- Unité Mixte de Recherche 216 Mère et Enfant Face aux Infections Tropicales, Institut de Recherche pour le Développement (IRD), Unité de formation et de recherche de Pharmacie, Paris Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon
| | - Talleh Almelli
- Unité Mixte de Recherche 216 Mère et Enfant Face aux Infections Tropicales, Institut de Recherche pour le Développement (IRD), Unité de formation et de recherche de Pharmacie, Paris
| | - Camille Debue
- Unité Mixte de Recherche 216 Mère et Enfant Face aux Infections Tropicales, Institut de Recherche pour le Développement (IRD), Unité de formation et de recherche de Pharmacie, Paris
| | - Vincent Foumane Ngane
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon
| | - Joseph Djaman Allico
- Unité de Recherche Neurobiologie et Développement, Unité Propre de Recherche 3294, Centre National de la Recherche Scientifique, Université Paris-Sud XI, Orsay Laboratoire de Pharmacodynamie Biochimique, Unité de Formation et de Recherche Biosciences, Université de Cocody Département de Biochimie, Institut Pasteur de Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Solange Whegang Youdom
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon
| | - Leonardo K Basco
- Unité de Recherche 198, Unité de Recherche des Maladies Infectieuses et Tropicales Emergentes, IRD, Faculté de Médecine La Timone, Aix-Marseille Université, Marseille, France Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon
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12
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Emergence of resistance to atovaquone-proguanil in malaria parasites: insights from computational modeling and clinical case reports. Antimicrob Agents Chemother 2014; 58:4504-14. [PMID: 24867967 DOI: 10.1128/aac.02550-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The usefulness of atovaquone-proguanil (AP) as an antimalarial treatment is compromised by the emergence of atovaquone resistance during therapy. However, the origin of the parasite mitochondrial DNA (mtDNA) mutation conferring atovaquone resistance remains elusive. Here, we report a patient-based stochastic model that tracks the intrahost emergence of mutations in the multicopy mtDNA during the first erythrocytic parasite cycles leading to the malaria febrile episode. The effect of mtDNA copy number, mutation rate, mutation cost, and total parasite load on the mutant parasite load per patient was evaluated. Computer simulations showed that almost any infected patient carried, after four to seven erythrocytic cycles, de novo mutant parasites at low frequency, with varied frequencies of parasites carrying varied numbers of mutant mtDNA copies. A large interpatient variability in the size of this mutant reservoir was found; this variability was due to the different parameters tested but also to the relaxed replication and partitioning of mtDNA copies during mitosis. We also report seven clinical cases in which AP-resistant infections were treated by AP. These provided evidence that parasiticidal drug concentrations against AP-resistant parasites were transiently obtained within days after treatment initiation. Altogether, these results suggest that each patient carries new mtDNA mutant parasites that emerge before treatment but are killed by high starting drug concentrations. However, because the size of this mutant reservoir is highly variable from patient to patient, we propose that some patients fail to eliminate all of the mutant parasites, repeatedly producing de novo AP treatment failures.
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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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Quashie NB, Duah NO, Abuaku B, Quaye L, Ayanful-Torgby R, Akwoviah GA, Kweku M, Johnson JD, Lucchi NW, Udhayakumar V, Duplessis C, Kronmann KC, Koram KA. A SYBR Green 1-based in vitro test of susceptibility of Ghanaian Plasmodium falciparum clinical isolates to a panel of anti-malarial drugs. Malar J 2013; 12:450. [PMID: 24341604 PMCID: PMC3878558 DOI: 10.1186/1475-2875-12-450] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/10/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Based on report of declining efficacy of chloroquine, Ghana shifted to the use of artemisinin-based combination therapy (ACT) in 2005 as the first-line anti-malarial drug. Since then, there has not been any major evaluation of the efficacy of anti-malarial drugs in Ghana in vitro. The sensitivity of Ghanaian Plasmodium falciparum isolates to anti-malarial drugs was, therefore, assessed and the data compared with that obtained prior to the change in the malaria treatment policy. METHODS A SYBR Green 1 fluorescent-based in vitro drug sensitivity assay was used to assess the susceptibility of clinical isolates of P. falciparum to a panel of 12 anti-malarial drugs in three distinct eco-epidemiological zones in Ghana. The isolates were obtained from children visiting health facilities in sentinel sites located in Hohoe, Navrongo and Cape Coast municipalities. The concentration of anti-malarial drug inhibiting parasite growth by 50% (IC50) for each drug was estimated using the online program, ICEstimator. RESULTS Pooled results from all the sentinel sites indicated geometric mean IC50 values of 1.60, 3.80, 4.00, 4.56, 5.20, 6.11, 10.12, 28.32, 31.56, 93.60, 107.20, and 8952.50 nM for atovaquone, artesunate, dihydroartemisin, artemether, lumefantrine, amodiaquine, mefloquine, piperaquine, chloroquine, tafenoquine, quinine, and doxycycline, respectively. With reference to the literature threshold value indicative of resistance, the parasites showed resistance to all the test drugs except the artemisinin derivatives, atovaquone and to a lesser extent, lumefantrine. There was nearly a two-fold decrease in the IC50 value determined for chloroquine in this study compared to that determined in 2004 (57.56 nM). This observation is important, since it suggests a significant improvement in the efficacy of chloroquine, probably as a direct consequence of reduced drug pressure after cessation of its use. Compared to that measured prior to the change in treatment policy, significant elevation of artesunate IC50 value was observed. The results also suggest the existence of possible cross-resistance among some of the test drugs. CONCLUSION Ghanaian P. falciparum isolates, to some extent, have become susceptible to chloroquine in vitro, however the increasing trend in artesunate IC50 value observed should be of concern. Continuous monitoring of ACT in Ghana is recommended.
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Affiliation(s)
- Neils B Quashie
- Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana.
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15
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Bastien D, Ebert MCCJC, Forge D, Toulouse J, Kadnikova N, Perron F, Mayence A, Huang TL, Vanden Eynde JJ, Pelletier JN. Fragment-Based Design of Symmetrical Bis-benzimidazoles as Selective Inhibitors of the Trimethoprim-Resistant, Type II R67 Dihydrofolate Reductase. J Med Chem 2012; 55:3182-92. [DOI: 10.1021/jm201645r] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dominic Bastien
- Département de Biochimie, Université de Montréal, C.P. 6128, Succ.
Centre-ville Montréal, Québec H3C 3J7, Canada
| | - Maximilian C. C. J. C. Ebert
- Département de Biochimie, Université de Montréal, C.P. 6128, Succ.
Centre-ville Montréal, Québec H3C 3J7, Canada
| | - Delphine Forge
- Laboratoire de Chimie Organique, Université de Mons-UMONS, 20 Place du Parc,
B-7000 Mons, Belgium
| | - Jacynthe Toulouse
- Département de Biochimie, Université de Montréal, C.P. 6128, Succ.
Centre-ville Montréal, Québec H3C 3J7, Canada
| | - Natalia Kadnikova
- Département
de Chimie, Université de Montréal, C.P. 6128, Succursale
Centre-ville Montréal, Québec H3C 3J7, Canada
| | - Florent Perron
- Laboratoire de Chimie Organique, Université de Mons-UMONS, 20 Place du Parc,
B-7000 Mons, Belgium
| | - Annie Mayence
- Division of Basic Pharmaceutical
Sciences, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, Louisiana 70125, United States
| | - Tien L. Huang
- Division of Basic Pharmaceutical
Sciences, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, Louisiana 70125, United States
| | | | - Joelle N. Pelletier
- Département de Biochimie, Université de Montréal, C.P. 6128, Succ.
Centre-ville Montréal, Québec H3C 3J7, Canada
- Département
de Chimie, Université de Montréal, C.P. 6128, Succursale
Centre-ville Montréal, Québec H3C 3J7, Canada
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16
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Afonso A, Neto Z, Castro H, Lopes D, Alves AC, Tomás AM, Rosário VD. Plasmodium chabaudi chabaudi malaria parasites can develop stable resistance to atovaquone with a mutation in the cytochrome b gene. Malar J 2010; 9:135. [PMID: 20492669 PMCID: PMC2881937 DOI: 10.1186/1475-2875-9-135] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 05/21/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium falciparum, has developed resistance to many of the drugs in use. The recommended treatment policy is now to use drug combinations. The atovaquone-proguanil (AP) drug combination, is one of the treatment and prophylaxis options. Atovaquone (ATQ) exerts its action by inhibiting plasmodial mitochondria electron transport at the level of the cytochrome bc1 complex. Plasmodium falciparum in vitro resistance to ATQ has been associated with specific point mutations in the region spanning codons 271-284 of the cytochrome b gene. ATQ -resistant Plasmodium yoelii and Plasmodium berghei lines have been obtained and resistant lines have amino acid mutations in their CYT b protein sequences. Plasmodium chabaudi model for studying drug-responses and drug-resistance selection is a very useful rodent malaria model but no ATQ resistant parasites have been reported so far. The aim of this study was to determine the ATQ sensitivity of the P. chabaudi clones, to select a resistant parasite line and to perform genotypic characterization of the cytb gene of these clones. METHODS To select for ATQ resistance, Plasmodium. chabaudi chabaudi clones were exposed to gradually increasing concentrations of ATQ during several consecutive passages in mice. Plasmodium chabaudi cytb gene was amplified and sequenced. RESULTS ATQ resistance was selected from the clone AS-3CQ. In order to confirm whether an heritable genetic mutation underlies the response of AS-ATQ to ATQ, the stability of the drug resistance phenotype in this clone was evaluated by measuring drug responses after (i) multiple blood passages in the absence of the drug, (ii) freeze/thawing of parasites in liquid nitrogen and (iii) transmission through a mosquito host, Anopheles stephensi. ATQ resistance phenotype of the drug-selected parasite clone kept unaltered. Therefore, ATQ resistance in clone AS-ATQ is genetically encoded. The Minimum Curative Dose of AS-ATQ showed a six-fold increase in MCD to ATQ relative to AS-3CQ. CONCLUSIONS A mutation was found on the P. chabaudi cytb gene from the AS-ATQ sample a substitution at the residue Tyr268 for an Asn, this mutation is homologous to the one found in P. falciparum isolates resistant to ATQ.
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Affiliation(s)
- Ana Afonso
- Unit of Medical Parasitology and Microbiology (UPMM)/IHMT Rua da Junqueira 100, 1349-008 Lisbon, Portugal.
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17
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Abstract
We discuss a case of atovaquone-proguanil treatment failure in a child from Mozambique, recently arrived in North America. Four weeks after completing therapy, symptomatic parasitemia recurred, caused by Plasmodium falciparum parasites bearing a Tyr268Ser mutation in cytochrome b. We review the literature concerning atovaquone-proguanil resistance, and emphasize the importance of follow-up and consideration of resistance where patients have relapsed symptoms.
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18
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First case of emergence of atovaquone-proguanil resistance in Plasmodium falciparum during treatment in a traveler in Comoros. Antimicrob Agents Chemother 2008; 52:2283-4. [PMID: 18411319 DOI: 10.1128/aac.00282-08] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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19
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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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20
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Blondé R, Naudin J, Bigirimana Z, Holvoet L, Fenneteau O, Vitoux C, Bourdon O, Angoulvant F, Lorrot M, D’Ortenzio E, Bourrillon A, Le Bras J, Matheron S, Faye A. Tolérance et efficacité de l’atovaquone-proguanil dans le traitement du paludisme d’importation à Plasmodium falciparum de l’enfant en France métropolitaine : expérience d’un centre hospitalier parisien. Arch Pediatr 2008; 15:245-52. [DOI: 10.1016/j.arcped.2007.10.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2007] [Revised: 09/23/2007] [Accepted: 10/14/2007] [Indexed: 11/24/2022]
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21
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Khositnithikul R, Tan-Ariya P, Mungthin M. In vitro atovaquone/proguanil susceptibility and characterization of the cytochrome b gene of Plasmodium falciparum from different endemic regions of Thailand. Malar J 2008; 7:23. [PMID: 18226262 PMCID: PMC2265725 DOI: 10.1186/1475-2875-7-23] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Accepted: 01/28/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The emergence of Plasmodium falciparum resistant to most currently used antimalarial drugs is the major problem in malaria control along the Thai-Myanmar and Thai-Cambodia borders. Although artemisinin-based combination therapy has been recommended for the treatment of multidrug-resistant falciparum malaria, these combinations are not available for some people, such as travelers from North America. A fixed-dose combination of atovaquone and proguanil (Malarone) has been proved to be effective for the treatment and prophylaxis of malaria which is already approved by countries in North America and Europe. Determination of the phenotypes and genotypes related to atovaquone/proguanil response in Thai isolates of P. falciparum will be useful for rationale drug use. The main purpose of this study was to explore the in vitro atovaquone/proguanil susceptibility of recently adapted Thai isolates of P. falciparum. Genotypic characterization of the cytb gene of these isolates was also determined since it has been reported that point mutations, particularly codon 268 in the cytochrome b gene (cytb) have been linked to atovaquone/proguanil treatment failure. METHODS Eighty three P. falciparum isolates collected during 1998 to 2005 from four different multidrug resistance areas of Thailand were determined for the in vitro atovaquone/proguanil susceptibilities using radioisotopic assay. Mutations in the cytb gene were determined by PCR-RFLP and sequence analysis. RESULTS The mean atovaquone and proguanil IC50 was 3.4 nM and 36.5 muM, respectively. All 83 Thai isolates were atovaquone sensitive. None of the 83 isolates contained the mutations at codon 268 of the cytb gene. DNA sequencing of the cytb gene of 20 parasite isolates showed no other mutations. CONCLUSION In agreement with a recent efficacy study of atovaquone/proguanil, the present information indicates that atovaquone/proguanil can be one of the drugs of choice for the treatment and prophylaxis of multidrug-resistant falciparum malaria in Thailand.
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Affiliation(s)
- Rommanee Khositnithikul
- Department of Parasitology, Phramongkutklao College of Medicine, Ratchawithi Rd, Bangkok 10400, Thailand.
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22
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Smilkstein MJ, Forquer I, Kanazawa A, Kelly JX, Winter RW, Hinrichs DJ, Kramer DM, Riscoe MK. A drug-selected Plasmodium falciparum lacking the need for conventional electron transport. Mol Biochem Parasitol 2008; 159:64-8. [PMID: 18308406 DOI: 10.1016/j.molbiopara.2008.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 01/11/2008] [Accepted: 01/15/2008] [Indexed: 10/22/2022]
Abstract
Mitochondrial electron transport is essential for survival in Plasmodium falciparum, making the cytochrome (cyt) bc(1) complex an attractive target for antimalarial drug development. Here we report that P. falciparum cultivated in the presence of a novel cyt bc(1) inhibitor underwent a fundamental transformation in biochemistry to a phenotype lacking a requirement for electron transport through the cyt bc(1) complex. Growth of the drug-selected parasite clone (SB1-A6) is robust in the presence of diverse cyt bc(1) inhibitors, although electron transport is fully inhibited by these same agents. This transformation defies expected molecular-based concepts of drug resistance, has important implications for the study of cyt bc(1) as an antimalarial drug target, and may offer a glimpse into the evolutionary future of Plasmodium.
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Affiliation(s)
- Martin J Smilkstein
- Medical Research Service, Department of Veterans Affairs Medical Center, Portland, OR 97239, USA.
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23
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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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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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25
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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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26
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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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27
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Happi CT, Gbotosho GO, Folarin OA, Milner D, Sarr O, Sowunmi A, Kyle DE, Milhous WK, Wirth DF, Oduola AMJ. Confirmation of emergence of mutations associated with atovaquone-proguanil resistance in unexposed Plasmodium falciparum isolates from Africa. Malar J 2006; 5:82. [PMID: 17020611 PMCID: PMC1594577 DOI: 10.1186/1475-2875-5-82] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Accepted: 10/04/2006] [Indexed: 11/16/2022] Open
Abstract
Background In vitro and in vivo resistance of Plasmodium falciparum to atovaquone or atovaquone-proguanil hydrochloride combination has been associated to two point mutations in the parasite cytochrome b (cytb) gene (Tyr268Ser and Tyr268Asn). However, little is known about the prevalence of codon-268 mutations in natural populations of P. falciparum without previous exposure to the drug in Africa. Methods The prevalence of codon-268 mutations in the cytb gene of African P. falciparum isolates from Nigeria, Malawi and Senegal, where atovaquone-proguanil has not been introduced for treatment of malaria was assessed. Genotyping of the cytb gene in isolates of P. falciparum was performed by PCR-restriction fragment length polymorphism and confirmed by sequencing. Results 295 samples from Nigeria (111), Malawi (91) and Senegal (93) were successfully analyzed for detection of either mutant Tyr268Ser or Tyr268Asn. No case of Ser268 or Asn268 was detected in cytb gene of parasites from Malawi or Senegal. However, Asn268 was detected in five out of 111 (4.5%) unexposed P. falciparum isolates from Nigeria. In addition, one out of these five mutant Asn268 isolates showed an additional cytb mutation leading to a Pro266Thr substitution inside the ubiquinone reduction site. Conclusion No Tyr268Ser mutation is found in cytb of P. falciparum isolates from Nigeria, Malawi or Senegal. This study reports for the first time cytb Tyr268Asn mutation in unexposed P. falciparum isolates from Nigeria. The emergence in Africa of P. falciparum isolates with cytb Tyr268Asn mutation is a matter of serious concern. Continuous monitoring of atovaquone-proguanil resistant P. falciparum in Africa is warranted for the rational use of this new antimalarial drug, especially in non-immune travelers.
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Affiliation(s)
- Christian T Happi
- Malaria Research Laboratories, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Nigeria
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
| | - Grace O Gbotosho
- Malaria Research Laboratories, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Nigeria
| | - Onikepe A Folarin
- Malaria Research Laboratories, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Nigeria
| | - Danny Milner
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
| | - Ousmane Sarr
- Laboratory of Bacteriology and Virology, Dantec Hospital, Dakar, Senegal
| | - Akintunde Sowunmi
- Malaria Research Laboratories, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Nigeria
| | - Dennis E Kyle
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Springs, MD, USA
| | - Wilbur K Milhous
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Springs, MD, USA
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
| | - Ayoade MJ Oduola
- Special Programme for Research and Training in Tropical Diseases (WHO/TDR), Geneva, Switzerland
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28
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Clinical atovaquone-proguanil resistance of Plasmodium falciparum associated with cytochrome b codon 268 mutations. Microbes Infect 2006; 8:2599-604. [PMID: 16962361 DOI: 10.1016/j.micinf.2006.07.011] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Accepted: 07/12/2006] [Indexed: 11/22/2022]
Abstract
Plasmodium falciparum resistance to atovaquone-proguanil has so far been associated with Y268S or Y268N mutations in cytochrome b, although these changes were identified in only seven of the 11 treatment failures. Here, we describe 10 new cases of atovaquone-proguanil treatment failures among which the parasite resistance was confirmed in six cases, either by identifying correct plasma drug concentrations or by observing in vitro atovaquone resistance. Resistance was consistently associated with codon 268 mutations (Y268S or a previously unidentified mutation, Y268C). Notably, mutations were not detected before the treatment but only after the drug exposure.
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29
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Le Bras J, Musset L, Clain J. [Antimalarial drug resistance]. Med Mal Infect 2006; 36:401-5. [PMID: 16854546 DOI: 10.1016/j.medmal.2006.05.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Accepted: 05/19/2006] [Indexed: 11/30/2022]
Abstract
Drug resistant malaria is mostly due to Plasmodium falciparum, the highly prevalent species in tropical Africa, Amazon, and Southeast Asia. P. falciparum is responsible for severe involvement of fever or anemia causing more than a million deaths per year. Rationale for treatment is becoming weak as multiple drug resistance against well-tolerated drugs develops. P. falciparum drug resistant malaria originates from chromosomal mutations. Analyses using molecular, genetic and biochemical approaches showed that: 1) impaired uptake of chloroquine by the parasite vacuole is a common characteristic of resistant strains, this phenotype correlates with pfmdr1 and pfcrt gene mutations; 2) one S108N to four (N51I, C59R, I164L) point mutations of dihydrofolate reductase, the enzyme target of antifolinics (pyrimethamine and proguanil), give moderate to high level of resistance to these drugs; 3) resistance to sulfonamides and sulfones involves mutations of dihydropteroate synthase (A437G, K540E), their enzyme target, impairing their capacity to potentiate antifolinic drugs; 4) resistance to atovaquone plus proguanil involves one single mutation on atovaquone target, cytochrome b (Y268S, C or N); 5) resistance to mefloquine is thought to be linked to the over expression of pfmdr1, a pump expelling toxic waste from eukaryotic cells. P. falciparum resistance levels may differ according to places and time, depending on malaria transmission and drug pressure. Coupling in vivo to in vitro tests, and using molecular tests is essential for the surveillance of replacement drugs. Low cost biochemical tools are urgently needed for a prospective monitoring of resistance.
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Affiliation(s)
- J Le Bras
- Laboratoire de parasitologie, EA 209, université René-Descartes, CNR paludisme, hôpital Bichat-Claude-Bernard, 75018 Paris, France.
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Pradines B, Hovette P, Fusai T, Atanda HL, Baret E, Cheval P, Mosnier J, Callec A, Cren J, Amalvict R, Gardair JP, Rogier C. Prevalence of in vitro resistance to eleven standard or new antimalarial drugs among Plasmodium falciparum isolates from Pointe-Noire, Republic of the Congo. J Clin Microbiol 2006; 44:2404-8. [PMID: 16825356 PMCID: PMC1489504 DOI: 10.1128/jcm.00623-06] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Accepted: 05/11/2006] [Indexed: 11/20/2022] Open
Abstract
We determined the level of in vitro resistance of Plasmodium falciparum parasites to standard antimalarial drugs, such as chloroquine, quinine, amodiaquine, halofantrine, mefloquine, cycloguanil, and pyrimethamine, and to new compounds, such as dihydroartemisinin, doxycycline, atovaquone, and lumefantrine. The in vitro resistance to chloroquine reached 75.5%. Twenty-eight percent of the isolates were intermediate or had reduced susceptibility to quinine. Seventy-six percent and 96% of the tested isolates showed in vitro resistance or intermediate susceptibilities to cycloguanil and pyrimethamine, respectively. Only 2% of the parasites demonstrated in vitro resistance to monodesethylamodiaquine. No resistance was shown with halofantrine, lumefantrine, dihydroartemisinin, or atovaquone. Halofantrine, mefloquine, and lumefantrine demonstrated high correlation. No cross-resistance was identified between responses to monodesethyl-amodiaquine, dihydroartemisinin, atovaquone, and cycloguanil. Since the level of chloroquine resistance in vitro exceed an unacceptable upper limit, high rates of in vitro resistance to pyrimethamine and cycloguanil and diminution of the susceptibility to quinine, antimalarial drugs used in combination, such as amodiaquine, artemisinin derivatives, mefloquine, lumefantrine, or atovaquone, seem to be appropriate alternatives for the first line of treatment of acute, uncomplicated P. falciparum malaria.
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Affiliation(s)
- Bruno Pradines
- IMTSSA, URBEP, Bd. C. Livon, Parc le Pharo, BP 46, 13998 Marseille Armées, France.
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