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Narang G, Jakhan J, Tamang S, Yadav K, Singh V. Characterization of drug resistance genes in Indian Plasmodium falciparum and Plasmodium vivax field isolates. Acta Trop 2024; 255:107218. [PMID: 38636585 DOI: 10.1016/j.actatropica.2024.107218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 03/21/2024] [Accepted: 04/15/2024] [Indexed: 04/20/2024]
Abstract
One of the major challenges for malaria control and elimination is the spread and emergence of antimalarial drug resistance. Mutations in Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) field isolates for five drug resistance genes viz. crt, mdr1, dhps, dhfr and kelch known to confer resistance to choloroquine (CQ), sulfadoxine-pyrimethamine (SP) and artemisinin (ART) and its derivatives were analyzed. A total of 342 symptomatic isolates of P. falciparum (Pf) and P. vivax (Pv) from 1993 to 2014 were retrieved from malaria parasite repository at National Institute of Malaria Research (NIMR). Sample DNA was extracted from dried blood spots and various targeted single nucleotide polymorphisms (SNPs) associated with antimalarial drug resistance were analysed for these isolates. 72S (67.7%) and 76T (83.8%) mutations along with SVMNT haplotype (67.7%) predominated the study population for Pfcrt. The most prevalent SNPs were 108N (73.2%) and 437G (24.8%) and the most prevalent haplotypes were ACNRNI (51.9%) and SAKAA (74.5%) in Pfdhfr and Pfdhps respectively. Only two mutations in Pfmdr1, 86Y (26.31%) and 184F (56.26%), were seen frequently in our study population. No mutations associated with Pfk13 were observed. For Pv, all the studied isolates showed two Pvdhps mutations, 383G and 553G, and two Pfdhfr mutations, 58R and 117N. Similarly, three mutations, viz. 958M, 908L and 1076L were found in Pvmdr1. No variations were observed in Pvcrt-o and Pvk12 genes. Overall, our study demonstrates an increase in mutations associated with SP resistance in both Pf and Pv, however, no single nucleotide polymorphisms (SNPs) associated with ART resistance have been observed for either species. Various SNPs associated with CQ resistance were seen in Pf; whereas only Pvmdr1 associated resistant SNPs were observed in Pv. Therefore, molecular characterization of drug resistance genes is essential for timely monitoring and prevention of malaria by identifying the circulating drug resistant parasites in the country.
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Affiliation(s)
- Geetika Narang
- ICMR-National Institute of Malaria Research (NIMR), Sector-8, Dwarka, New Delhi 110077, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Jahnvi Jakhan
- ICMR-National Institute of Malaria Research (NIMR), Sector-8, Dwarka, New Delhi 110077, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Suman Tamang
- ICMR-National Institute of Malaria Research (NIMR), Sector-8, Dwarka, New Delhi 110077, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Karmveer Yadav
- ICMR-National Institute of Malaria Research (NIMR), Sector-8, Dwarka, New Delhi 110077, India
| | - Vineeta Singh
- ICMR-National Institute of Malaria Research (NIMR), Sector-8, Dwarka, New Delhi 110077, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India.
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Miatmoko A, Octavia RT, Araki T, Annoura T, Sari R. Advancing liposome technology for innovative strategies against malaria. Saudi Pharm J 2024; 32:102085. [PMID: 38690211 PMCID: PMC11059525 DOI: 10.1016/j.jsps.2024.102085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 04/23/2024] [Indexed: 05/02/2024] Open
Abstract
This review discusses the potential of liposomes as drug delivery systems for antimalarial therapies. Malaria continues to be a significant cause of mortality and morbidity, particularly among children and pregnant women. Drug resistance due to patient non-compliance and troublesome side effects remains a significant challenge in antimalarial treatment. Liposomes, as targeted and efficient drug carriers, have garnered attention owing to their ability to address these issues. Liposomes encapsulate hydrophilic and/or hydrophobic drugs, thus providing comprehensive and suitable therapeutic drug delivery. Moreover, the potential of passive and active drug delivery enables drug concentration in specific target tissues while reducing adverse effects. However, successful liposome formulation is influenced by various factors, including drug physicochemical characteristics and physiological barriers encountered during drug delivery. To overcome these challenges, researchers have explored modifications in liposome nanocarriers to achieve efficient drug loading, controlled release, and system stability. Computational approaches have also been adopted to predict liposome system stability, membrane integrity, and drug-liposome interactions, improving formulation development efficiency. By leveraging computational methods, optimizing liposomal drug delivery systems holds promise for enhancing treatment efficacy and minimizing side effects in malaria therapy. This review consolidates the current understanding and highlights the potential of liposome strategies against malaria.
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Affiliation(s)
- Andang Miatmoko
- Department of Pharmaceutical Science, Faculty of Pharmacy, Universitas Airlangga, Campus C UNAIR Mulyorejo, Surabaya 60115, Indonesia
- Stem Cell Research and Development Center, Universitas Airlangga, 2 Floor Institute of Tropical Disease Building, Campus C UNAIR Mulyorejo, Surabaya 60115, Indonesia
- Nanotechnology and Drug Delivery System Research Group, Faculty of Pharmacy, Universitas Airlangga, Campus C UNAIR Mulyorejo, Surabaya 60115, Indonesia
| | - Rifda Tarimi Octavia
- Master Program of Pharmaceutical Sciences, Faculty of Pharmacy, Universitas Airlangga, Campus C UNAIR Mulyorejo, Surabaya 60115, Indonesia
| | - Tamasa Araki
- Department of Parasitology, National Institute of Infectious Diseases (NIID), 1-23-1 Toyama, Shinju-ku, Tokyo 162-8640, Japan
| | - Takeshi Annoura
- Department of Parasitology, National Institute of Infectious Diseases (NIID), 1-23-1 Toyama, Shinju-ku, Tokyo 162-8640, Japan
| | - Retno Sari
- Department of Pharmaceutical Science, Faculty of Pharmacy, Universitas Airlangga, Campus C UNAIR Mulyorejo, Surabaya 60115, Indonesia
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Audibert C, Aspinall A, Tchouatieu AM, Hugo P. Evaluation of Segmentation, Rotation, and Geographic Delivery Approaches for Deployment of Multiple First-Line Treatment (MFT) to Respond to Antimalarial Drug Resistance in Africa: A Qualitative Study in Seven Sub-Sahara Countries. Trop Med Infect Dis 2024; 9:93. [PMID: 38787026 PMCID: PMC11125622 DOI: 10.3390/tropicalmed9050093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/19/2024] [Accepted: 04/20/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Several studies recently confirmed the emergence of resistance to antimalarial drugs in sub-Saharan Africa. Multiple first-line treatment (MFT) is one of the measures envisaged to respond to the emergence and spread of this resistance. The aim of this study was to identify the perceived advantages and disadvantages of several MFT deployment strategies and to better understand potential implementation drivers and barriers. METHODS A qualitative survey was conducted in seven sub-Saharan countries amongst key opinion leaders, national decision makers, and end users. A total of 200 individual interviews were conducted and findings were analyzed following a thematic inductive approach. RESULTS From a policy perspective, the new MFT intervention would require endorsement at the global, national, and regional levels to ensure its inclusion in guidelines. Funding of the MFT intervention could be a bottleneck due to costs associated with additional training of healthcare workers, adaptation of drug delivery mechanisms, and higher costs of drugs. Concerning the MFT deployment strategies, a slight preference for the segmentation strategy was expressed over the rotation and geographic approaches, due to the perception that a segmentation approach is already in place at country level. CONCLUSIONS The findings highlighted the need for a collective approach to MFT deployment through the engagement of stakeholders at all levels of malaria management.
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Affiliation(s)
- Celine Audibert
- Medicines for Malaria Venture (MMV), Route de Pre-Bois 20, 1215 Meyrin, Switzerland; (A.A.)
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Maiga H, Morrison RD, Duffy PE. Sanger sequencing and deconvolution of polyclonal infections: a quantitative approach to monitor drug-resistant Plasmodium falciparum. EBioMedicine 2024; 103:105115. [PMID: 38636200 PMCID: PMC11031737 DOI: 10.1016/j.ebiom.2024.105115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 03/27/2024] [Accepted: 03/29/2024] [Indexed: 04/20/2024] Open
Abstract
BACKGROUND Anti-malarial drug resistance in Plasmodium falciparum is a major public health problem in malaria-endemic regions. Although various technical improvements in sequencing methods have been introduced to identify SNPs, the conventional approach with current tools does not discriminate mixed infections, and thus can be improved for more sensitive surveillance of anti-malarial resistance to better inform control strategies. METHODS We developed a computational approach for deconvolution of chromatograms generated by standard Sanger sequencing of PCR amplicons in order to quantify molecular marker variants of anti-malarial drug resistance genes [Plasmodium falciparum dihydropteorate synthase (Pfdhps) and P. falciparum dihydrofolate reductase (Pfdhfr)]. We validated this computational approach using mixtures of V1/S and FCR3 at varying proportions between 0 and 100%, then applied it to field samples collected in Doneguebougou, Mali in 2018. We determined the mean fraction of resistance alleles in individual samples, as well as the prevalence of infections carrying resistant parasites. FINDINGS We observed a highly significant correlation between the predicted and measured proportions of V1/S and FCR3 alleles in mixed laboratory samples (all p < 0.001). Among field samples, the mean fraction of resistant Pfdhps alleles was 4.7% 431V, 95.9% 436F/A, 49.9% 437G, 0.0% 540E, 1.2% 581G and 1.5% 613S/T; corresponding prevalences were 50.0%, 100%, 72.5%, 0.0%, 25.0%, and 12.5%, respectively. The mean fraction of resistant Pfdhfr alleles was 0.6% 16V, 11.1% 50R, 89.0% 51I, 98.3% 59R, 74.7% 108T/N, 8.6% 140L and 8.7% 164L; corresponding prevalences were 12.5%, 75.0%, 100%, 100%, 100%, 50.0%, and 28.6%, respectively. We identified two new point mutations on the Pfdhps gene at codons D484T and D545N. INTERPRETATION Computational deconvolution of sequencing chromatograms can discriminate varying proportions of antimalarial drug-sensitive versus -resistant alleles. This cost-effective and quantitative variant-sequencing approach will be useful for population-based surveys that characterize mixed infections at the individual level to survey known and unknown mutations in P. falciparum drug-resistance genes. FUNDING This work was supported by the Division of Intramural Research of the National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH). HM was supported by the African Postdoctoral Training Initiative (APTI) Fellowship program jointly managed by the US NIH, The African Academy of Sciences (AAS) and Bill & Melinda Gates Foundation (BMGF); Grant Reference Number: APTI-18-01.
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Affiliation(s)
- Hamma Maiga
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 29 Lincoln Drive, Bethesda, MD, 20892, USA; Institut National de Santé Publique (INSP), Ministère de la Santé et du Développement Social (MSDS), Bamako, BP: 1771, Mali.
| | - Robert D Morrison
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 29 Lincoln Drive, Bethesda, MD, 20892, USA
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 29 Lincoln Drive, Bethesda, MD, 20892, USA
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Rosenthal PJ, Asua V, Bailey JA, Conrad MD, Ishengoma DS, Kamya MR, Rasmussen C, Tadesse FG, Uwimana A, Fidock DA. The emergence of artemisinin partial resistance in Africa: how do we respond? THE LANCET. INFECTIOUS DISEASES 2024:S1473-3099(24)00141-5. [PMID: 38552654 DOI: 10.1016/s1473-3099(24)00141-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/17/2024] [Accepted: 02/19/2024] [Indexed: 04/21/2024]
Abstract
Malaria remains one of the most important infectious diseases in the world, with the greatest burden in sub-Saharan Africa, primarily from Plasmodium falciparum infection. The treatment and control of malaria is challenged by resistance to most available drugs, but partial resistance to artemisinins (ART-R), the most important class for the treatment of malaria, was until recently confined to southeast Asia. This situation has changed, with the emergence of ART-R in multiple countries in eastern Africa. ART-R is mediated primarily by single point mutations in the P falciparum kelch13 protein, with several mutations present in African parasites that are now validated resistance mediators based on clinical and laboratory criteria. Major priorities at present are the expansion of genomic surveillance for ART-R mutations across the continent, more frequent testing of the efficacies of artemisinin-based regimens against uncomplicated and severe malaria in trials, more regular assessment of ex-vivo antimalarial drug susceptibilities, consideration of changes in treatment policy to deter the spread of ART-R, and accelerated development of new antimalarial regimens to overcome the impacts of ART-R. The emergence of ART-R in Africa is an urgent concern, and it is essential that we increase efforts to characterise its spread and mitigate its impact.
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Affiliation(s)
- Philip J Rosenthal
- Department of Medicine, University of California, San Francisco, CA, USA.
| | - Victor Asua
- Infectious Diseases Research Collaboration, Kampala, Uganda; University of Tübingen, Tübingen, Germany
| | - Jeffrey A Bailey
- Center for Computational Molecular Biology, Brown University, Providence, RI, USA; Departments of Pathology and Laboratory Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
| | - Melissa D Conrad
- Department of Medicine, University of California, San Francisco, CA, USA
| | - Deus S Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania; Department of Biochemistry, Kampala International University in Tanzania, Dar es Salaam, Tanzania; School of Public Health, Harvard University, Boston, MA, USA
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda; Department of Medicine, Makerere University, Kampala, Uganda
| | | | - Fitsum G Tadesse
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia; London School of Hygiene and Tropical Medicine, London, UK
| | - Aline Uwimana
- Rwanda Biomedical Center, Kigali, Rwanda; Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - David A Fidock
- Department of Microbiology and Immunology and Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
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Matrevi SA, Adams T, Tandoh KZ, Opoku-Agyeman P, Bruku S, Ennuson NA, Apau-Danso PK, Fiagbedzi E, Avornyo M, Myers CJ, Futagbi J, Hagan OC, Abuaku B, Koram KA, Awandare G, Quashie NB, Duah-Quashie NO. Putative molecular markers of Plasmodium falciparum resistance to antimalarial drugs in malaria parasites from Ghana. FRONTIERS IN EPIDEMIOLOGY 2024; 4:1279835. [PMID: 38456076 PMCID: PMC10910922 DOI: 10.3389/fepid.2024.1279835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 01/29/2024] [Indexed: 03/09/2024]
Abstract
Introduction Antimalarial drugs including artemisinin-based combination therapy (ACT) regimens and sulphadoxine-pyrimethamine (SP) are used in Ghana for malaria therapeutics and prophylaxis respectively. The genetic basis of Plasmodium falciparum development of drug resistance involves single nucleotide polymorphisms in genes encoding proteins for multiple cellular and metabolic processes. The prevalence of single nucleotide polymorphisms in nine P. falciparum genes linked to ACT and SP resistance in the malaria parasite population was determined. Methods Archived filter paper blood blot samples from patients aged 9 years and below with uncomplicated malaria reporting at 10 sentinel sites located in three ecological zones for the Malaria Therapeutic Efficacy Studies were used. The samples used were collected from 2007-2018 malaria transmission seasons and mutations in the genes were detected using PCR and Sanger sequencing. Results In all 1,142 samples were used for the study. For falcipain-2 gene (pffp2), Sanger sequencing was successful for 872 samples and were further analysed. The prevalence of the mutants was 45% (392/872) with pffp2 markers V51I and S59F occurring in 15.0% (128/872) and 3.0% (26/872) of the samples respectively. Prevalence of other P. falciparum gene mutations: coronin (pfcoronin) was 44.8% (37/90); cysteine desulfurase (pfnfs) was 73.9% (68/92); apicoplast ribosomal protein S10 (pfarps10) was 36.8% (35/95); ferredoxin (pffd) was 8.8% (8/91); multidrug resistance protein-1 (pfmrp1) was 95.2.0% (80/84); multidrug resistance protein-2 (pfmrp2) was 91.4% (32/35); dihydrofolate reductase (pfdhfr) was 99.0% (84/85); dihydropteroate synthase (pfdhps) was 72% (68/95). Discussion The observation of numerous mutations in these genes of interest in the Ghanaian isolates, some of which have been implicated in delayed parasite clearance is of great interest. The presence of these genotypes may account for the decline in the efficacies of ACT regimens being used to treat uncomplicated malaria in the country. The need for continuous monitoring of these genetic markers to give first-hand information on parasite susceptibility to antimalarial drugs to inform policy makers and stakeholders in malaria elimination in the country is further discussed.
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Affiliation(s)
- Sena Adzoa Matrevi
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Tryphena Adams
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Kwesi Zandoh Tandoh
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Philip Opoku-Agyeman
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Selassie Bruku
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Nana Aba Ennuson
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Paa Kwesi Apau-Danso
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Emmanuel Fiagbedzi
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Mary Avornyo
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Charles James Myers
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Joy Futagbi
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Oheneba Charles Hagan
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Benjamin Abuaku
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Kwadwo Ansah Koram
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Gordon Awandare
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Neils Ben Quashie
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
- Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, University of Ghana, Accra, Ghana
| | - Nancy Odurowah Duah-Quashie
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
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Chinedu SN, Bella-Omunagbe M, Okafor E, Afolabi R, Adebiyi E. Computational Studies on 6-Pyruvoyl Tetrahydropterin Synthase (6-PTPS) of Plasmodium falciparum. Bioinform Biol Insights 2024; 18:11779322241230214. [PMID: 38333003 PMCID: PMC10851736 DOI: 10.1177/11779322241230214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 01/16/2024] [Indexed: 02/10/2024] Open
Abstract
6-Pyruvoyl tetrahydropterin synthase (6-PTPS) is a lyase involved in the synthesis of tetrahydrobiopterin. In Plasmodium species where dihydroneopterin aldolase (DHNA) is absent, it acts in the folate biosynthetic pathway necessary for the growth and survival of the parasite. The 6-pyruvoyl tetrahydropterin synthase of Plasmodium falciparum (PfPTPS) has been identified as a potential antimalarial drug target. This study identified potential inhibitors of PfPTPS using molecular docking techniques. Molecular docking and virtual screening of 62 compounds including the control to the deposited Protein Data Bank (PDB) structure was carried out using AutoDock Vina in PyRx. Five of the compounds, N,N-dimethyl-N'-[4-oxo-6-(2,2,5-trimethyl-1,3-dioxolan-4-yl)-3H-pteridin-2-yl]methanimidamide (140296439), 2-amino-6-[(1R)-3-cyclohexyl-1-hydroxypropyl]-3H-pteridin-4-one (140296495), 2-(2,3-dihydroxypropyl)-8,9-dihydro-6H-pyrimido[2,1-b]pteridine-7,11-dione (144380406), 2-(dimethylamino)-6-[(2,2-dimethyl-1,3-dioxolan-4-yl)-hydroxymethyl]-3H-pteridin-4-one (135573878), and [1-acetyloxy-1-(2-methyl-4-oxo-3H-pteridin-6-yl)propan-2-yl] acetate (136075207), showed better binding affinity than the control ligand, biopterin (135449517), and were selected and screened. Three conformers of 140296439 with the binding energy of -7.2, -7.1, and -7.0 kcal/mol along with 140296495 were better than the control at -5.7 kcal/mol. In silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) studies predicted good pharmacokinetic properties of all the compounds while reporting a high risk of irritant toxicity in 140296439 and 144380406. The study highlights the five compounds, 140296439, 140296495, 144380406, 135573878 and 136075207, as potential inhibitors of PfPTPS and possible compounds for antimalarial drug development.
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Affiliation(s)
- Shalom N Chinedu
- Department of Biochemistry, Covenant University, Ota, Nigeria
- Covenant University Public Health & Well-being Research Cluster (CUPHWERC), Covenant University, Ota, Nigeria
| | - Mercy Bella-Omunagbe
- Department of Biochemistry, Covenant University, Ota, Nigeria
- Covenant Applied Informatics and Communication—Africa Centre of Excellence (CApIC-ACE), Covenant University, Ota, Nigeria
| | - Esther Okafor
- Department of Biochemistry, Covenant University, Ota, Nigeria
- Covenant University Bioinformatics Research (CUBre), Covenant University, Ota, Nigeria
| | - Rufus Afolabi
- Department of Biochemistry, Covenant University, Ota, Nigeria
- Covenant University Bioinformatics Research (CUBre), Covenant University, Ota, Nigeria
| | - Ezekiel Adebiyi
- Covenant Applied Informatics and Communication—Africa Centre of Excellence (CApIC-ACE), Covenant University, Ota, Nigeria
- Covenant University Bioinformatics Research (CUBre), Covenant University, Ota, Nigeria
- Department of Computer & Information Sciences, Covenant University, Ota, Nigeria
- Division of Applied Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany
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Karthika A, Hemavathy N, Amala M, Rajamanikandan S, Veerapandian M, Prabhu D, Vetrivel U, Jung Chen C, Jeyaraj Pandian C, Jeyakanthan J. Structural and functional characterization of 6-phosphogluconate dehydrogenase in Plasmodium falciparum (3D7) and identification of its potent inhibitors. J Biomol Struct Dyn 2024; 42:2058-2074. [PMID: 37599457 DOI: 10.1080/07391102.2023.2248271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 04/09/2023] [Indexed: 08/22/2023]
Abstract
The malarial parasite Plasmodium falciparum predominantly causes severe malaria and deaths worldwide. Moreover, resistance developed by P. falciparum to frontline drugs in recent years has markedly increased malaria-related deaths in South Asian Countries. Ribulose 5-phosphate and NADPH synthesized by Pentose Phosphate Pathway (PPP) act as a direct precursor for nucleotide synthesis and P. falciparum survival during oxidative challenges in the intra-erythrocytic growth phase . In the present study, we have elucidated the structure and functional characteristics of 6-phosphogluconate dehydrogenase (6PGD) in P. falciparum and have identified potent hits against 6PGD by pharmacophore-based virtual screening with ZINC and ChemBridge databases. Molecular docking and Molecular dynamics simulation, binding free energies (MMGBSA & MMPBSA), and Density Functional Theory (DFT) calculations were integratively employed to validate and prioritize the most potential hits. The 6PGD structure was found to have an open and closed conformation during MD simulation. The apo form of 6PGD was found to be in closed conformation, while a open conformation attributed to facilitating binding of cofactor. It was also inferred from the conformational analysis that the small domain of 6PGD has a high influence in altering the conformation that may aid in open/closed conformation of 6PGD. The top three hits identified using pharmacophore hypotheses were ChemBridge_11084819, ChemBridge_80178394, and ChemBridge_17912340. Though all three hits scored a high glide score, MMGBSA, and favorable ADMET properties, ChemBridge_11084819 and ChemBrdige_17912340 showed higher stability and binding free energy. Moreover, these hits also featured stable H-bond interactions with the active loop of 6PGD with binding free energy comparable to substrate-bound complex. Therefore, the ChemBridge_11084819 and ChemBridge_17912340 moieties demonstrate to have high therapeutic potential against 6PGD in P. falciparum.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Alagesan Karthika
- Structural Biology and Bio-Computing Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India
| | - Nagarajan Hemavathy
- Structural Biology and Bio-Computing Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India
- Centre for Bioinformatics, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Mathimaran Amala
- Structural Biology and Bio-Computing Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India
| | - Sundaraj Rajamanikandan
- Centre for Drug Discovery, Karpagam Academy of Higher Education, Coimbatore, Tamil Nadu, India
| | - Malaisamy Veerapandian
- Structural Biology and Bio-Computing Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India
| | - Dhamodharan Prabhu
- Centre for Drug Discovery, Karpagam Academy of Higher Education, Coimbatore, Tamil Nadu, India
| | - Umashankar Vetrivel
- ICMR-National Institute of Traditional Medicine, Nehru Nagar, Belagavi, Karnataka, India
- ICMR-National Institute for Research in Tuberculosis, Chennai, Tamil Nadu, India
| | - Chun Jung Chen
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Chitra Jeyaraj Pandian
- Department of Biotechnology, Dr. Umayal Ramanathan College for Women, Karaikudi, Tamil Nadu, India
| | - Jeyaraman Jeyakanthan
- Structural Biology and Bio-Computing Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India
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Eccleston RC, Manko E, Campino S, Clark TG, Furnham N. A computational method for predicting the most likely evolutionary trajectories in the stepwise accumulation of resistance mutations. eLife 2023; 12:e84756. [PMID: 38132182 PMCID: PMC10807863 DOI: 10.7554/elife.84756] [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: 11/07/2022] [Accepted: 12/21/2023] [Indexed: 12/23/2023] Open
Abstract
Pathogen evolution of drug resistance often occurs in a stepwise manner via the accumulation of multiple mutations that in combination have a non-additive impact on fitness, a phenomenon known as epistasis. The evolution of resistance via the accumulation of point mutations in the DHFR genes of Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) has been studied extensively and multiple studies have shown epistatic interactions between these mutations determine the accessible evolutionary trajectories to highly resistant multiple mutations. Here, we simulated these evolutionary trajectories using a model of molecular evolution, parameterised using Rosetta Flex ddG predictions, where selection acts to reduce the target-drug binding affinity. We observe strong agreement with pathways determined using experimentally measured IC50 values of pyrimethamine binding, which suggests binding affinity is strongly predictive of resistance and epistasis in binding affinity strongly influences the order of fixation of resistance mutations. We also infer pathways directly from the frequency of mutations found in isolate data, and observe remarkable agreement with the most likely pathways predicted by our mechanistic model, as well as those determined experimentally. This suggests mutation frequency data can be used to intuitively infer evolutionary pathways, provided sufficient sampling of the population.
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Affiliation(s)
- Ruth Charlotte Eccleston
- Department of Infection Biology, London School of Hygiene and Tropical MedicineLondonUnited Kingdom
| | - Emilia Manko
- Department of Infection Biology, London School of Hygiene and Tropical MedicineLondonUnited Kingdom
| | - Susana Campino
- Department of Infection Biology, London School of Hygiene and Tropical MedicineLondonUnited Kingdom
| | - Taane G Clark
- Department of Infection Biology, London School of Hygiene and Tropical MedicineLondonUnited Kingdom
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical MedicineLondonUnited Kingdom
| | - Nicholas Furnham
- Department of Infection Biology, London School of Hygiene and Tropical MedicineLondonUnited Kingdom
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10
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Kajubi R, Ainsworth J, Baker K, Richardson S, Bonnington C, Rassi C, Achan J, Magumba G, Rubahika D, Nabakooza J, Tibenderana J, Nuwa A, Opigo J. A hybrid effectiveness-implementation study protocol to assess the effectiveness and chemoprevention efficacy of implementing seasonal malaria chemoprevention in five districts in Karamoja region, Uganda. Gates Open Res 2023; 7:14. [PMID: 38196920 PMCID: PMC10774186 DOI: 10.12688/gatesopenres.14287.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2024] [Indexed: 01/11/2024] Open
Abstract
Background The World Health Organization (WHO) recommends seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine (SPAQ) for children aged 3 to 59 months, living in areas where malaria transmission is highly seasonal. However, due to widespread prevalence of resistance markers, SMC has not been implemented at scale in East and Southern Africa. An initial study in Uganda showed that SMC with SPAQ was feasible, acceptable, and protective against malaria in eligible children in Karamoja region. Nonetheless, exploration of alternative regimens is warranted since parasite resistance threats persist. Objective The study aims to test the effectiveness of SMC with Dihydroartemisinin-piperaquine (DP) or SPAQ (DP-SMC & SPAQ-SMC), chemoprevention efficacy as well as the safety and tolerability of DP compared to that of SPAQ among 3-59 months old children in Karamoja region, an area of Uganda where malaria transmission is highly seasonal. Methods A Type II hybrid effectiveness-implementation study design consisting of four components: 1) a cluster randomized controlled trial (cRCT) using passive surveillance to establish confirmed malaria cases in children using both SPAQ and DP; 2a) a prospective cohort study to determine the chemoprevention efficacy of SPAQ and DP (if SPAQ or DP clears sub-patent infection and provides 28 days of protection from new infection) and whether drug concentrations and/or resistance influence the ability to clear and prevent infection; 2b) a sub study examining pharmacokinetics of DP in children between 3 to <6 months; 3) a resistance markers study in children 3-59 months in the research districts plus the standard intervention districts to measure changes in resistance marker prevalence over time and finally; 4) a process evaluation. Discussion This study evaluates the effects of SPAQ-SMC versus DP-SMC on clinical malaria in vulnerable children in the context of high parasite SP resistance, whilst informing on the best implementation strategies. Conclusion This study will inform malaria policy in high-burden countries, specifically on utility of SMC outside the sahel, and contribute to progress in malaria control.
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Affiliation(s)
| | | | - Kevin Baker
- Technical, Malaria Consortium, London, UK
- Department of Global Public Health, Karolinska Institute, Stockholm, Sweden
| | | | | | | | - Jane Achan
- Technical, Malaria Consortium, London, UK
| | | | - Denis Rubahika
- National Malaria Control Division, Ministry of Health of Uganda, Kampala, Uganda
| | - Jane Nabakooza
- National Malaria Control Division, Ministry of Health of Uganda, Kampala, Uganda
| | | | | | - Jimmy Opigo
- National Malaria Control Division, Ministry of Health of Uganda, Kampala, Uganda
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11
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Nkemngo FN, Raissa LW, Nguete DN, Ndo C, Fru-Cho J, Njiokou F, Wanji S, Wondji CS. Geographical emergence of sulfadoxine-pyrimethamine drug resistance-associated P. falciparum and P. malariae alleles in co-existing Anopheles mosquito and asymptomatic human populations across Cameroon. Antimicrob Agents Chemother 2023; 67:e0058823. [PMID: 37947766 PMCID: PMC10720508 DOI: 10.1128/aac.00588-23] [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: 05/07/2023] [Accepted: 09/28/2023] [Indexed: 11/12/2023] Open
Abstract
Malaria molecular surveillance remains critical in detecting and tracking emerging parasite resistance to anti-malarial drugs. The current study employed molecular techniques to determine Plasmodium species prevalence and characterize the genetic diversity of Plasmodium falciparum and Plasmodium malariae molecular markers of sulfadoxine-pyrimethamine resistance in humans and wild Anopheles mosquito populations in Cameroon. Anopheles mosquito collections and parasitological survey were conducted in villages to determine Plasmodium species infection, and genomic phenotyping of anti-folate resistance was accomplished by sequencing the dihydrofolate-reductase (dhfr) and dihydropteroate-synthase (dhps) genes of naturally circulating P. falciparum and P. malariae isolates. The malaria prevalence in Elende was 73.5% with the 5-15 years age group harboring significant P. falciparum (27%) and P. falciparum + P. malariae (19%) infections. The polymorphism breadth of the pyrimethamine-associated Pfdhfr marker revealed a near fixation (94%) of the triple-mutant -A16I51R59N108I164. The Pfdhps backbone mediating sulfadoxine resistance reveals a high frequency of the V431A436G437K540A581A613 alleles (20.8%). Similarly, the Pmdhfr N50K55L57R58S59S114F168I170 haplotype (78.4%) was predominantly detected in the asexual blood stage. In contrast, the Pmdhps- S436A437occured at 37.2% frequency. The combined quadruple N50K55L57R58S59S114F168I170_ S436G437K540A581A613 (31.9%) was the major circulating haplotype with similar frequency in humans and mosquitoes. This study highlights the increasing frequency of the P. malariae parasite mostly common in asymptomatic individuals with apparent P. falciparum infection. Interventions directed at reducing malaria transmission such as the scaling-up of SP are favoring the emergence and spread of multiple drug-resistant alleles between the human and mosquito host systems.
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Affiliation(s)
- Francis N. Nkemngo
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Lymen W. Raissa
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Daniel N. Nguete
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Cyrille Ndo
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | - Jerome Fru-Cho
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
- Centre for Infection Biology and Translational Research, Forzi Institute, Buea, Cameroon
| | - Flobert Njiokou
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
| | - Charles S. Wondji
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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12
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Suphakhonchuwong N, Rungsihirunrat K, Kuesap J. Surveillance of drug resistance molecular markers in Plasmodium vivax before and after introduction of dihydroartemisinin and piperaquine in Thailand: 2009-2019. Parasitol Res 2023; 122:2871-2883. [PMID: 37725258 DOI: 10.1007/s00436-023-07977-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 09/12/2023] [Indexed: 09/21/2023]
Abstract
Resistance to antimalarial drugs is a serious issue around the world. Widespread Plasmodium vivax and P. falciparum coinfections are commonly found in Thailand. Dihydroartemisinin and piperaquine (DHA-PPQ) have been used as first-line treatments for P. falciparum since 2015, and chloroquine (CQ) and primaquine (PQ) have remained first-line drugs for P. vivax for more than 60 years. Coinfections may lead parasites to evolve with regard to genetics under selective drug pressure. This study is aimed at investigating genes linked to antimalarial resistance in P. vivax before and after introduction of DHA-PPQ as a new drug regimen in Thailand. A total of 400 P. vivax isolates were collected from samples along the Thai-Myanmar and Thai-Malaysian borders before (2009-2015) and after (2016-2019) introduction of DHA-PPQ. Genomic DNA of P. vivax was obtained and subjected to analysis of five drug resistance-associated genes (Pvdhfr, Pvdhps, Pvmdr1, Pvcrt-o, and PvK12) by nested polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), and nucleotide sequencing. A high prevalence of Pvdhfr was found in both endemic areas over the period. The quadruple (57I/58R/61M/117T) Pvdhfr haplotype was predominant in both periods in both endemic areas. Although the wild-type haplotype of Pvdhps was predominant in Thai-Malaysian isolates in both periods, a single mutant haplotype (383G) was dominant in Thai-Myanmar isolates during both periods. A low prevalence of the Pvmdr1 976F mutation was found in both periods among Thai-Myanmar isolates. A significant decrease in Pvmdr1 976F was identified in Thai-Malaysian isolates from the second period (p < 0.01). Only one nonsynonymous mutation of Pvcrt-o (193E) and one synonymous mutation of PvK12 (R584) were detected in four isolates (4.7%) and one isolate (0.5%) in the first period among Thai-Myanmar isolates, respectively. Thus, with limited clinical efficacy data, the low prevalence of drug-resistance markers may suggest that there is a low prevalence of P. vivax-resistant strains and that the current drug regimen for P. vivax is still effective for treating this P. vivax parasite population. Continued surveillance of antimalarial drug resistance markers and monitoring of clinical drug efficacy should be conducted for epidemiological and policy implications.
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Affiliation(s)
| | | | - Jiraporn Kuesap
- Faculty of Allied Health Sciences, Thammasat University, Pathumthani, 12120, Thailand.
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13
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Roh ME, Zongo I, Haro A, Huang L, Somé AF, Yerbanga RS, Conrad MD, Wallender E, Legac J, Aweeka F, Ouédraogo JB, Rosenthal PJ. Seasonal Malaria Chemoprevention Drug Levels and Drug Resistance Markers in Children With or Without Malaria in Burkina Faso: A Case-Control Study. J Infect Dis 2023; 228:926-935. [PMID: 37221018 PMCID: PMC10547452 DOI: 10.1093/infdis/jiad172] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 04/04/2023] [Accepted: 05/20/2023] [Indexed: 05/25/2023] Open
Abstract
BACKGROUND Despite scale-up of seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine (SP-AQ) in children 3-59 months of age in Burkina Faso, malaria incidence remains high, raising concerns regarding SMC effectiveness and selection of drug resistance. Using a case-control design, we determined associations between SMC drug levels, drug resistance markers, and presentation with malaria. METHODS We enrolled 310 children presenting at health facilities in Bobo-Dioulasso. Cases were SMC-eligible children 6-59 months of age diagnosed with malaria. Two controls were enrolled per case: SMC-eligible children without malaria; and older (5-10 years old), SMC-ineligible children with malaria. We measured SP-AQ drug levels among SMC-eligible children and SP-AQ resistance markers among parasitemic children. Conditional logistic regression was used to compute odds ratios (ORs) comparing drug levels between cases and controls. RESULTS Compared to SMC-eligible controls, children with malaria were less likely to have any detectable SP or AQ (OR, 0.33 [95% confidence interval, .16-.67]; P = .002) and have lower drug levels (P < .05). Prevalences of mutations mediating high-level SP resistance were rare (0%-1%) and similar between cases and SMC-ineligible controls (P > .05). CONCLUSIONS Incident malaria among SMC-eligible children was likely due to suboptimal levels of SP-AQ, resulting from missed cycles rather than increased antimalarial resistance to SP-AQ.
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Affiliation(s)
- Michelle E Roh
- Institute for Global Health Sciences, Malaria Elimination Initiative, University of California, San Francisco
| | - Issaka Zongo
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Alassane Haro
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Liusheng Huang
- Department of Clinical Pharmacy, University of California, San Francisco
| | | | | | | | - Erika Wallender
- Department of Clinical Pharmacy, University of California, San Francisco
| | - Jennifer Legac
- Department of Medicine, University of California, San Francisco
| | - Francesca Aweeka
- Department of Clinical Pharmacy, University of California, San Francisco
| | - Jean-Bosco Ouédraogo
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
- Institut des Sciences et Techniques, Bobo-Dioulasso, Burkina Faso
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14
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Tarama CW, Soré H, Siribié M, Débé S, Kinda R, Ganou A, Nonkani WG, Tiendrebeogo F, Bantango W, Yira K, Sagnon A, Ilboudo S, Hien EY, Guelbéogo MW, Sagnon NF, Traoré Y, Ménard D, Gansané A. Plasmodium falciparum drug resistance-associated mutations in isolates from children living in endemic areas of Burkina Faso. Malar J 2023; 22:213. [PMID: 37474966 PMCID: PMC10360335 DOI: 10.1186/s12936-023-04645-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 07/11/2023] [Indexed: 07/22/2023] Open
Abstract
BACKGROUND Artemisinin-based combinations therapy (ACT) is the current frontline curative therapy for uncomplicated malaria in Burkina Faso. Sulfadoxine-pyrimethamine (SP) is used for the preventive treatment of pregnant women (IPTp), while SP plus amodiaquine (SP-AQ) is recommended for children under five in seasonal malaria chemoprevention (SMC). This study aimed to assess the proportions of mutations in the P. falciparum multidrug-resistance 1 (Pfmdr1), P. falciparum chloroquine resistance transporter (Pfcrt), P. falciparum dihydrofolate reductase (pfdhfr), and P. falciparum dihydropteroate synthase (pfdhps), genes from isolates collected during household surveys in Burkina Faso. METHODS Dried blood spots from Plasmodium falciparum-positive cases at three sites (Orodara, Gaoua, and Banfora) collected during the peak of transmission were analysed for mutations in Pfcrt (codons 72-76, 93, 97, 145, 218, 343, 350 and 353), Pfmdr-1 (codons 86, 184, 1034, 1042 and 1246) dhfr (codons 51, 59, 108, 164) and dhps (at codons 431, 436, 437, 540, 581, 613) genes using deep sequencing of multiplexed Polymerase chaine reaction (PCR) amplicons. RESULTS Of the 377 samples analysed, 346 (91.7%), 369 (97.9%), 368 (97.6%), and 374 (99.2%) were successfully sequenced for Pfcrt, Pfmdr-1, dhfr, and dhps, respectively. Most of the samples had a Pfcrt wild-type allele (89.3%). The 76T mutation was below 10%. The most frequent Pfmdr-1 mutation was detected at codon 184 (Y > F, 30.9%). The single mutant genotype (NFSND) predominated (66.7%), followed by the wild-type genotype (NYSND, 30.4%). The highest dhfr mutations were observed at codon 59R (69.8%), followed by codons 51I (66.6%) and 108 N (14.7%). The double mutant genotype (ACIRSI) predominated (52.4%). For mutation in the dhps gene, the highest frequency was observed at codon 437 K (89.3%), followed by codons 436 A (61.2%), and 613 S (14.4%). The double mutant genotype (IAKKAA) and the single mutant genotype (ISKKAA) were predominant (37.7% and 37.2%, respectively). The most frequent dhfr/dhps haplotypes were the triple mutant ACIRSI/IAKKAA (23%), the wild-type ACNCSI/ISKKAA (19%) and the double mutant ACIRSI/ISKKAA (14%). A septuple mutant ACIRNI/VAKKGA was observed in 2 isolates from Gaoua (0.5%). CONCLUSION The efficacy of ACT partner drugs and drugs used in IPTp and SMC does not appear to be affected by the low proportion of highly resistant mutants observed in this study. Continued monitoring, including molecular surveillance, is critical for decision-making on effective treatment policy in Burkina Faso.
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Affiliation(s)
| | - Harouna Soré
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | - Mafama Siribié
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | - Siaka Débé
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | - Réné Kinda
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | - Adama Ganou
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | - Wendyam Gérard Nonkani
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | - Farida Tiendrebeogo
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | - Winnie Bantango
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | - Kassoum Yira
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | - Aladari Sagnon
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | - Sonia Ilboudo
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | | | | | - NFale Sagnon
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso
| | - Yves Traoré
- Université Joseph KI-ZERBO, Ouagadougou, Burkina Faso
| | - Didier Ménard
- Malaria Genetic and Resistance Unit, Institut Pasteur, Université Paris Cité, INSERM U1201, 75015, Paris, France
- Malaria Parasite Biology and Vaccines, Institut Pasteur, Université Paris Cité, 75015, Paris, France
- Institute of Parasitology and Tropical Diseases, Université de Strasbourg, UR7292 Dynamics of Host-Pathogen Interactions, 67000, Strasbourg, France
- Laboratory of Parasitology and Medical Mycology, CHU Strasbourg, 67000, Strasbourg, France
| | - Adama Gansané
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso.
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15
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Holzschuh A, Lerch A, Gerlovina I, Fakih BS, Al-Mafazy AWH, Reaves EJ, Ali A, Abbas F, Ali MH, Ali MA, Hetzel MW, Yukich J, Koepfli C. Multiplexed ddPCR-amplicon sequencing reveals isolated Plasmodium falciparum populations amenable to local elimination in Zanzibar, Tanzania. Nat Commun 2023; 14:3699. [PMID: 37349311 PMCID: PMC10287761 DOI: 10.1038/s41467-023-39417-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 06/13/2023] [Indexed: 06/24/2023] Open
Abstract
Zanzibar has made significant progress toward malaria elimination, but recent stagnation requires novel approaches. We developed a highly multiplexed droplet digital PCR (ddPCR)-based amplicon sequencing method targeting 35 microhaplotypes and drug-resistance loci, and successfully sequenced 290 samples from five districts covering both main islands. Here, we elucidate fine-scale Plasmodium falciparum population structure and infer relatedness and connectivity of infections using an identity-by-descent (IBD) approach. Despite high genetic diversity, we observe pronounced fine-scale spatial and temporal parasite genetic structure. Clusters of near-clonal infections on Pemba indicate persistent local transmission with limited parasite importation, presenting an opportunity for local elimination efforts. Furthermore, we observe an admixed parasite population on Unguja and detect a substantial fraction (2.9%) of significantly related infection pairs between Zanzibar and the mainland, suggesting recent importation. Our study provides a high-resolution view of parasite genetic structure across the Zanzibar archipelago and provides actionable insights for prioritizing malaria elimination efforts.
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Affiliation(s)
- Aurel Holzschuh
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Indiana, IN, USA.
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.
| | - Anita Lerch
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Indiana, IN, USA
| | - Inna Gerlovina
- EPPIcenter Research Program, Division of HIV, ID and Global Medicine, Department of Medicine, University of California, San Francisco, CA, USA
| | - Bakar S Fakih
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | | | - Erik J Reaves
- U.S. Centers for Disease Control and Prevention, President's Malaria Initiative, Dar es Salaam, United Republic of Tanzania
| | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Faiza Abbas
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Mohamed Haji Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Mohamed Ali Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Joshua Yukich
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
| | - Cristian Koepfli
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Indiana, IN, USA.
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16
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Guijarro MV, Kellish PC, Dib PE, Paciaroni NG, Nawab A, Andring J, Kulemina L, Borrero NV, Modenutti C, Feely M, Nasri E, Seifert RP, Luo X, Bennett RL, Shabashvili D, Licht JD, McKenna R, Roitberg A, Huigens RW, Kaye FJ, Zajac-Kaye M. First-in-class multifunctional TYMS nonclassical antifolate inhibitor with potent in vivo activity that prolongs survival. JCI Insight 2023; 8:e158798. [PMID: 37097751 PMCID: PMC10386886 DOI: 10.1172/jci.insight.158798] [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: 01/31/2022] [Accepted: 04/18/2023] [Indexed: 04/26/2023] Open
Abstract
Although thymidylate synthase (TYMS) inhibitors have served as components of chemotherapy regimens, the currently available inhibitors induce TYMS overexpression or alter folate transport/metabolism feedback pathways that tumor cells exploit for drug resistance, limiting overall benefit. Here we report a small molecule TYMS inhibitor that i) exhibited enhanced antitumor activity as compared with current fluoropyrimidines and antifolates without inducing TYMS overexpression, ii) is structurally distinct from classical antifolates, iii) extended survival in both pancreatic xenograft tumor models and an hTS/Ink4a/Arf null genetically engineered mouse tumor model, and iv) is well tolerated with equal efficacy using either intraperitoneal or oral administration. Mechanistically, we verify the compound is a multifunctional nonclassical antifolate, and using a series of analogs, we identify structural features allowing direct TYMS inhibition while maintaining the ability to inhibit dihydrofolate reductase. Collectively, this work identifies nonclassical antifolate inhibitors that optimize inhibition of thymidylate biosynthesis with a favorable safety profile, highlighting the potential for enhanced cancer therapy.
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Affiliation(s)
| | | | | | | | | | - Jacob Andring
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
| | | | | | - Carlos Modenutti
- Department of Biological Chemistry, Faculty of Exact and Natural Sciences, University of Buenos Aires, and
- Institute of Biological Chemistry of the Faculty of Exact and Natural Sciences (IQUIBICEN) CONICET, University City, Pab. II (CE1428EHA), Buenos Aires, Argentina
| | - Michael Feely
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Elham Nasri
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Robert P. Seifert
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, Florida, USA
| | | | - Richard L. Bennett
- Department of Medicine, University of Florida Health Cancer Center, Gainesville, Florida, USA
| | | | - Jonathan D. Licht
- Department of Medicine, University of Florida Health Cancer Center, Gainesville, Florida, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
| | - Adrian Roitberg
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | | | - Frederic J. Kaye
- Department of Medicine, University of Florida Health Cancer Center, Gainesville, Florida, USA
| | - Maria Zajac-Kaye
- Department of Anatomy and Cell Biology
- Department of Medicine, University of Florida Health Cancer Center, Gainesville, Florida, USA
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17
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Insight into molecular diagnosis for antimalarial drug resistance of Plasmodium falciparum parasites: A review. Acta Trop 2023; 241:106870. [PMID: 36849091 DOI: 10.1016/j.actatropica.2023.106870] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/20/2023] [Accepted: 02/22/2023] [Indexed: 02/27/2023]
Abstract
Malaria is an infectious disease transmitted by the female Anopheles mosquito and poses a severe threat to human health. At present, antimalarial drugs are the primary treatment for malaria. The widespread use of artemisinin-based combination therapies (ACTs) has dramatically reduced the number of malaria-related deaths; however, the emergence of resistance has the potential to reverse this progress. Accurate and timely diagnosis of drug-resistant strains of Plasmodium parasites via detecting molecular markers (such as Pfnhe1, Pfmrp, Pfcrt, Pfmdr1, Pfdhps, Pfdhfr, and Pfk13) is essential for malaria control and elimination. Here, we review the current techniques which commonly used for molecular diagnosis of antimalarial resistance in P. falciparum and discuss their sensitivities and specificities for different drug resistance-associated molecular markers, with the aim of providing insights into possible directions for future precise point-of-care testing (POCT) of antimalarial drug resistance of malaria parasites.
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Kajubi R, Ainsworth J, Baker K, Richardson S, Bonnington C, Rassi C, Achan J, Magumba G, Rubahika D, Nabakooza J, Tibenderana J, Nuwa A, Opigo J. A hybrid effectiveness-implementation study protocol to assess the effectiveness and chemoprevention efficacy of implementing seasonal malaria chemoprevention in five districts in Karamoja region, Uganda. Gates Open Res 2023. [DOI: 10.12688/gatesopenres.14287.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Background: The World Health Organization (WHO) recommends seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine for children aged 3 to 59 months, living in areas where malaria transmission is highly seasonal. However, due to widespread prevalence of resistance markers, SMC has not been implemented at scale in East and Southern Africa. An initial study in Uganda showed that SMC with SPAQ was feasible, acceptable, and protective against malaria in eligible children in Karamoja region. Nonetheless, exploration of alternative regimens is warranted since parasite resistance threats persist. Objective: The study aims to test the effectiveness of SMC with DP or SPAQ (DP-SMC & SPAQ-SMC), chemoprevention efficacy as well as the safety and tolerability of DP compared to that of SPAQ among 3-59 months old children in Karamoja region, an area of Uganda where malaria transmission is highly seasonal. Methods: A Type II hybrid effectiveness-implementation study design consisting of four components: 1) a cluster randomized controlled trial (cRCT) using passive surveillance to establish confirmed malaria cases in children using both SPAQ and DP; 2a) a prospective cohort study to determine the chemoprevention efficacy of SPAQ and DP (if SPAQ or DP clears sub-patent infection and provides 28 days of protection from new infection) and whether drug concentrations and/or resistance influence the ability to clear and prevent infection; 2b) a sub study examining pharmacokinetics of DP in children between 3 to <6 months; 3) a resistance markers study in children 3–59 months in the research districts plus the standard intervention districts to measure changes in resistance marker prevalence over time and finally; 4) a process evaluation. Discussion: This study evaluates the effects of a clinical intervention on relevant outcomes whilst collecting information on implementation. Conclusion: This study will inform malaria policy in high-burden countries and contribute to progress in malaria control.
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Oladejo DO, duselu GO, Dokunmu TM, Isewon I, Oyelade J, Okafor E, Iweala EEJ, Adebiyi E. In silico Structure Prediction, Molecular Docking, and Dynamic Simulation of Plasmodium falciparum AP2-I Transcription Factor. Bioinform Biol Insights 2023; 17:11779322221149616. [PMID: 36704725 PMCID: PMC9871981 DOI: 10.1177/11779322221149616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 12/18/2022] [Indexed: 01/22/2023] Open
Abstract
Plasmodium falciparum Apicomplexan Apetala 2 Invasion (PfAP2-I) transcription factor (TF) is a protein that regulates the expression of a subset of gene families involved in P. falciparum red blood cell (RBC) invasion. Inhibiting PfAP2-I TF with small molecules represents a potential new antimalarial therapeutic target to combat drug resistance, which this study aims to achieve. The 3D model structure of PfAP2-I was predicted ab initio using ROBETTA prediction tool and was validated using Save server 6.0 and MolProbity. Computed Atlas of Surface Topography of proteins (CASTp) 3.0 was used to predict the active sites of the PfAP2-I modeled structure. Pharmacophore modeling of the control ligand and PfAP2-I modeled structure was carried out using the Pharmit server to obtain several compounds used for molecular docking analysis. Molecular docking and postdocking studies were conducted using AutoDock vina and Discovery studio. The designed ligands' toxicity predictions and in silico drug-likeness were performed using the SwissADME predictor and OSIRIS Property Explorer. The modeled protein structure from the ROBETTA showed a validation result of 96.827 for ERRAT, 90.2% of the amino acid residues in the most favored region for the Ramachandran plot, and MolProbity score of 1.30 in the 98th percentile. Five (5) best hit compounds from molecular docking analysis were selected based on their binding affinity (between -8.9 and -11.7 Kcal/mol) to the active site of PfAP2-I and were considered for postdocking studies. For the absorption, distribution, metabolism, elimination, and toxicity (ADMET) properties, compound MCULE-7146940834 had the highest drug score (0.63) and drug-likeness (6.76). MCULE-7146940834 maintained a stable conformation within the flexible protein's active site during simulation. The good, estimated binding energies, drug-likeness, drug score, and molecular dynamics simulation interaction observed for MCULE-7146940834 against PfAP2-I show that MCULE-7146940834 can be considered a lead candidate for PfAP2-I inhibition. Experimental validations should be carried out to ascertain the efficacy of these predicted best hit compounds.
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Affiliation(s)
- David O Oladejo
- Covenant Applied Informatics and
Communication Africa Centre of Excellence (CApIC-ACE), Covenant University, Ota,
Nigeria
- Department of Biochemistry, College of
Science and Technology, Covenant University, Ota, Nigeria
| | - Gbolahan O duselu
- Department of Chemistry, College of
Science and Technology, Covenant University, Ota, Nigeria
| | - Titilope M Dokunmu
- Covenant Applied Informatics and
Communication Africa Centre of Excellence (CApIC-ACE), Covenant University, Ota,
Nigeria
- Department of Biochemistry, College of
Science and Technology, Covenant University, Ota, Nigeria
| | - Itunuoluwa Isewon
- Covenant Applied Informatics and
Communication Africa Centre of Excellence (CApIC-ACE), Covenant University, Ota,
Nigeria
- Department of Computer and Information
Science, College of Science and Technology, Covenant University, Ota, Nigeria
| | - Jelili Oyelade
- Covenant Applied Informatics and
Communication Africa Centre of Excellence (CApIC-ACE), Covenant University, Ota,
Nigeria
- Department of Computer and Information
Science, College of Science and Technology, Covenant University, Ota, Nigeria
| | - Esther Okafor
- Department of Biochemistry, College of
Science and Technology, Covenant University, Ota, Nigeria
| | - Emeka EJ Iweala
- Covenant Applied Informatics and
Communication Africa Centre of Excellence (CApIC-ACE), Covenant University, Ota,
Nigeria
- Department of Biochemistry, College of
Science and Technology, Covenant University, Ota, Nigeria
| | - Ezekiel Adebiyi
- Covenant Applied Informatics and
Communication Africa Centre of Excellence (CApIC-ACE), Covenant University, Ota,
Nigeria
- Department of Computer and Information
Science, College of Science and Technology, Covenant University, Ota, Nigeria
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Nwonuma CO, Balogun EA, Gyebi GA. Evaluation of Antimalarial Activity of Ethanolic Extract of Annona muricata L.: An in vivo and an in silico Approach. J Evid Based Integr Med 2023; 28:2515690X231165104. [PMID: 37019435 PMCID: PMC10084581 DOI: 10.1177/2515690x231165104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
Abstract
In Nigeria, Annona muricata L. has been used to treat a variety of ailments. The mechanism of the antimalarial activity of ethanolic leaf extract of Annona muricata (EEAML) was investigated using both an in vivo and an in silico approach. The experimental mice were divided into five groups: A-F. The mice in groups B-F were inoculated with Plasmodium berghei NK-65 and treated accordingly. Groups A and B are the negative and positive controls (infected and untreated), respectively. Group C received 10 mg/kg chloroquine (standard drug), whereas groups D-F received 100, 200, and 300 mg/kg body weight of the extract orally respectively. The mice were euthanized eight days after infection, and their liver and blood were collected and used in biochemical tests. Molecular docking was performed using the extract's HPLC compounds and Plasmodium falciparum proteins. In the suppressive, prophylactic, and curative tests, there was a significant decrease (p < 0.05) in parasitemia levels in groups treated with the extract compared to the positive control and standard drug. When compared to the positive control, there was a significant (p < 0.05) reduction in liver MDA, total cholesterol, and total triglyceride levels. The binding energies of luteolin and apigenin-pfprotein complexes were significantly (p < 0.05) higher compared to their respective references. The anti-plasmodial activity of the extract may result from its hypolipidemic effect, which deprives the parasite of essential lipid molecules needed for parasite growth, as well as from the inhibitory effects of apigenin and luteolin on specific proteins required for the Plasmodium metabolic pathway.
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Affiliation(s)
- Charles Obiora Nwonuma
- Department of Biochemistry, College of Pure and Applied Science, Landmark University, Omu-Aran, Kwara State, Nigeria
| | | | - Gideon Ampoma Gyebi
- Department of Biochemistry, Faculty of Science and Technology, Bingham University, Karu, Nigeria
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Boni MF. Breaking the cycle of malaria treatment failure. FRONTIERS IN EPIDEMIOLOGY 2022; 2:1041896. [PMID: 38455307 PMCID: PMC10910953 DOI: 10.3389/fepid.2022.1041896] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 11/28/2022] [Indexed: 03/09/2024]
Abstract
Treatment of symptomatic malaria became a routine component of the clinical and public health response to malaria after the second world war. However, all antimalarial drugs deployed against malaria eventually generated enough drug resistance that they had to be removed from use. Chloroquine, sulfadoxine-pyrimethamine, and mefloquine are well known examples of antimalarial drugs to which resistance did and still does ready evolve. Artemisinin-based combination therapies (ACTs) are currently facing the same challenge as artemisinin resistance is widespread in Southeast Asia and emerging in Africa. Here, I review some aspects of drug-resistance management in malaria that influence the strength of selective pressure on drug-resistant malaria parasites, as well as an approach we can take in the future to avoid repeating the common mistake of deploying a new drug and waiting for drug resistance and treatment failure to arrive. A desirable goal of drug-resistance management is to reduce selection pressure without reducing the overall percentage of patients that are treated. This can be achieved by distributing multiple first-line therapies (MFT) simultaneously in the population for the treatment of uncomplicated falciparum malaria, thereby keeping treatment levels high but the overall selection pressure exerted by each individual therapy low. I review the primary reasons that make MFT a preferred resistance management option in many malaria-endemic settings, and I describe two exceptions where caution and additional analyses may be warranted before deploying MFT. MFT has shown to be feasible in practice in many endemic settings. The continual improvement and increased coverage of genomic surveillance in malaria may allow countries to implement custom MFT strategies based on their current drug-resistance profiles.
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Affiliation(s)
- Maciej F. Boni
- Department of Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, United States
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
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Das S, Tripathy S, Das A, Sharma MK, Nag A, Hati AK, Roy S. Genomic characterization of Plasmodium falciparum genes associated with anti-folate drug resistance and treatment outcomes in eastern India: A molecular surveillance study from 2008 to 2017. Front Cell Infect Microbiol 2022; 12:865814. [PMID: 36583107 PMCID: PMC9794033 DOI: 10.3389/fcimb.2022.865814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 11/15/2022] [Indexed: 12/14/2022] Open
Abstract
Introduction After being used vigorously for the previous two decades to treat P. falciparum, chloroquine and sulfadoxine-pyrimethamine were replaced in 2009 with an artemisinin-based combination therapy (artesunate-sulfadoxine-pyrimethamine) in an effort to combat multidrug-resistant parasites. Methods We set out to assess the genetic variants of sulfadoxine-pyrimethamine resistance and the effectiveness of its treatment in eastern India prior to, during, and 6 to 8 years following the introduction of the new pharmacological regime. In 2008-2009, 318 P. falciparum-positive patients got the recommended doses of sulfadoxine-pyrimethamine. We used 379 additional isolates from 2015 to 2017 in addition to the 106 isolates from 2010. All 803 isolates from two study sites underwent in vitro sulfadoxine-pyrimethamine sensitivity testing and genomic characterisation of sulfadoxine-pyrimethamine resistance (pfdhfr and pfdhps). Results In Kolkata and Purulia, we observed early treatment failure in 30.7 and 14.4% of patients, respectively, whereas recrudescence was found in 8.1 and 13.4% of patients, respectively, in 2008-2009. In 2017, the proportion of in vitro pyrimethamine and sulfadoxine resistance steadily grew in Kolkata and Purulia despite a single use of sulfadoxine-pyrimethamine. Treatment failures with sulfadoxine-pyrimethamine were linked to quintuple or quadruple pfdhfr- pfdhps mutations (AICII-AGKAT, AICII-AGKAA, AICII-SGKGT, AICII-AGKAA, AICNI-AGKAA) in 2008-2009 (p < 0.001). The subsequent spread of mutant-haplotypes with higher in vitro sulfadoxine-pyrimethamine resistance (p < 0.001), such as the sextuple (dhfr-AIRNI+dhps-AGEAA, dhfr-ANRNL+dhps-AGEAA) and septuple (dhfr-AIRNI+dhps-AGEAT), mutations were observed in 2015-2017. Discussion This successive spread of mutations with high in vitro sulfadoxine-pyrimethamine resistance confirmed the progressive increase in antifolate resistance even after an 8-year withdrawal of sulfadoxine-pyrimethamine.
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Affiliation(s)
- Sabyasachi Das
- Department of Physiology, Faculty of Medicine, Manipal University College Malaysia, Melaka, Malaysia,Department of Human Physiology, Vidyasagar University, Midnapore, India
| | - Satyajit Tripathy
- Department of Pharmacology, Faculty of Health Sciences, School of Clinical Medicines, University of the Free State, Bloemfontein, South Africa
| | - Ankita Das
- Department of Human Physiology, Raja NL Khan Women’s College, Midnapore, India
| | | | - Ayan Nag
- Department of Physiology, Faculty of Medicine, Manipal University College Malaysia, Melaka, Malaysia
| | - Amiya Kumar Hati
- Department of Medical Entomology, Calcutta School of Tropical Medicine, Kolkata, West Bengal, India
| | - Somenath Roy
- Department of Human Physiology, Vidyasagar University, Midnapore, India,*Correspondence: Somenath Roy, ;
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Guerra AP, Olivera MJ, Cortés LJ, Chenet SM, Macedo de Oliveira A, Lucchi NW. Molecular surveillance for anti-malarial drug resistance and genetic diversity of Plasmodium falciparum after chloroquine and sulfadoxine-pyrimethamine withdrawal in Quibdo, Colombia, 2018. Malar J 2022; 21:306. [PMID: 36307852 PMCID: PMC9617338 DOI: 10.1186/s12936-022-04328-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 08/18/2022] [Indexed: 11/24/2022] Open
Abstract
Background Resistance to anti-malarial drugs is associated with polymorphisms in target genes and surveillance for these molecular markers is important to detect the emergence of mutations associated with drug resistance and signal recovering sensitivity to anti-malarials previously used. Methods The presence of polymorphisms in genes associated with Plasmodium falciparum resistance to chloroquine and sulfadoxine-pyrimethamine was evaluated by Sanger sequencing, in 85 P. falciparum day of enrollment samples from a therapeutic efficacy study of artemether–lumefantrine conducted in 2018–2019 in Quibdo, Colombia. Samples were genotyped to assess mutations in pfcrt (codons 72–76), pfdhfr (codons 51, 59, 108, and 164), and pfdhps genes (codons 436, 437, 540, and 581). Further, the genetic diversity of infections using seven neutral microsatellites (NMSs) (C2M34, C3M69, Poly α, TA1, TA109, 2490, and PfPK2) was assessed. Results All isolates carried mutant alleles for pfcrt (K76T and N75E), and for pfdhfr (N51I and S108N), while for pfdhps, mutations were observed only for codon A437G (32/73, 43.8%). Fifty samples (58.8%) showed a complete neutral microsatellites (NMS) profile. The low mean number of alleles (2 ± 0.57) per locus and mean expected heterozygosity (0.17 ± 0.03) showed a reduced genetic diversity. NMS multilocus genotypes (MMG) were built and nine MMG were identified. Conclusions Overall, these findings confirm the fixation of chloroquine and pyrimethamine-resistant alleles already described in the literature, implying that these drugs are not currently appropriate for use in Colombia. In contrast, mutations in the pfdhps gene were only observed at codon 437, an indication that full resistance to sulfadoxine has not been achieved in Choco. MMGs found matched the clonal lineage E variant 1 previously reported in northwestern Colombia. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04328-x.
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Affiliation(s)
| | | | | | - Stella M Chenet
- Instituto de Investigaciones en Ciencias Biomédicas, Universidad Ricardo Palma, Lima, Perú
| | - Alexandre Macedo de Oliveira
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, GA, Atlanta, USA
| | - Naomi W Lucchi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, GA, Atlanta, USA
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Zhao W, Li X, Yang Q, Zhou L, Duan M, Pan M, Qin Y, Li X, Wang X, Zeng W, Zhao H, Sun K, Zhu W, Afrane Y, Amoah LE, Abuaku B, Duah-Quashie NO, Huang Y, Cui L, Yang Z. In vitro susceptibility profile of Plasmodium falciparum clinical isolates from Ghana to antimalarial drugs and polymorphisms in resistance markers. Front Cell Infect Microbiol 2022; 12:1015957. [PMID: 36310880 PMCID: PMC9614232 DOI: 10.3389/fcimb.2022.1015957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 09/28/2022] [Indexed: 11/21/2022] Open
Abstract
Drug resistance in Plasmodium falciparum compromises the effectiveness of antimalarial therapy. This study aimed to evaluate the extent of drug resistance in parasites obtained from international travelers returning from Ghana to guide the management of malaria cases. Eighty-two clinical parasite isolates were obtained from patients returning from Ghana in 2016–2018, of which 29 were adapted to continuous in vitro culture. Their geometric mean IC50 values to a panel of 11 antimalarial drugs, assessed using the standard SYBR Green-I drug sensitivity assay, were 2.1, 3.8, 1.0, 2.7, 17.2, 4.6, 8.3, 8.3, 19.6, 55.1, and 11,555 nM for artemether, artesunate, dihydroartemisinin, lumefantrine, mefloquine, piperaquine, naphthoquine, pyronaridine, chloroquine, quinine, and pyrimethamine, respectively. Except for chloroquine and pyrimethamine, the IC50 values for other tested drugs were below the resistance threshold. The mean ring-stage survival assay value was 0.8%, with four isolates exceeding 1%. The mean piperaquine survival assay value was 2.1%, all below 10%. Mutations associated with chloroquine resistance (pfcrt K76T and pfmdr1 N86Y) were scarce, consistent with the discontinuation of chloroquine a decade ago. Instead, the pfmdr1 86N-184F-1246D haplotype was predominant, suggesting selection by the extensive use of artemether-lumefantrine. No mutations in the pfk13 propeller domain were detected. The pfdhfr/pfdhps quadruple mutant IRNGK associated with resistance to sulfadoxine-pyrimethamine reached an 82% prevalence. In addition, five isolates had pfgch1 gene amplification but, intriguingly, increased susceptibilities to pyrimethamine. This study showed that parasites originating from Ghana were susceptible to artemisinins and the partner drugs of artemisinin-based combination therapies. Genotyping drug resistance genes identified the signature of selection by artemether-lumefantrine. Parasites showed substantial levels of resistance to the antifolate drugs. Continuous resistance surveillance is necessary to guide timely changes in drug policy.
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Affiliation(s)
- Wei Zhao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Xinxin Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Qi Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Longcan Zhou
- Department of Infectious Diseases, Shanglin County People’s Hospital, Guangxi, China
| | - Mengxi Duan
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Maohua Pan
- Department of Infectious Diseases, Shanglin County People’s Hospital, Guangxi, China
| | - Yucheng Qin
- Department of Infectious Diseases, Shanglin County People’s Hospital, Guangxi, China
| | - Xiaosong Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Xun Wang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Weilin Zeng
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Hui Zhao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Kemin Sun
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Wenya Zhu
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Yaw Afrane
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Linda Eva Amoah
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Benjamin Abuaku
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Nancy Odurowah Duah-Quashie
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Yaming Huang
- Department of Protozoan Diseases, Guangxi Zhuang Autonomous Region Center for Disease Prevention and Control, Nanning, China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
- *Correspondence: Zhaoqing Yang, ; Liwang Cui,
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
- *Correspondence: Zhaoqing Yang, ; Liwang Cui,
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Temporal trends in molecular markers of drug resistance in Plasmodium falciparum in human blood and profiles of corresponding resistant markers in mosquito oocysts in Asembo, western Kenya. Malar J 2022; 21:265. [PMID: 36100912 PMCID: PMC9472345 DOI: 10.1186/s12936-022-04284-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/30/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Over the last two decades, the scale-up of vector control and changes in the first-line anti-malarial, from chloroquine (CQ) to sulfadoxine-pyrimethamine (SP) and then to artemether-lumefantrine (AL), have resulted in significant decreases in malaria burden in western Kenya. This study evaluated the long-term effects of control interventions on molecular markers of Plasmodium falciparum drug resistance using parasites obtained from humans and mosquitoes at discrete time points. METHODS Dried blood spot samples collected in 2012 and 2017 community surveys in Asembo, Kenya were genotyped by Sanger sequencing for markers associated with resistance to SP (Pfdhfr, Pfdhps), CQ, AQ, lumefantrine (Pfcrt, Pfmdr1) and artemisinin (Pfk13). Temporal trends in the prevalence of these markers, including data from 2012 to 2017 as well as published data from 1996, 2001, 2007 from same area, were analysed. The same markers from mosquito oocysts collected in 2012 were compared with results from human blood samples. RESULTS The prevalence of SP dhfr/dhps quintuple mutant haplotype C50I51R59N108I164/S436G437E540A581A613 increased from 19.7% in 1996 to 86.0% in 2012, while an increase in the sextuple mutant haplotype C50I51R59N108I164/H436G437E540A581A613 containing Pfdhps-436H was found from 10.5% in 2012 to 34.6% in 2017. Resistant Pfcrt-76 T declined from 94.6% in 2007 to 18.3% in 2012 and 0.9% in 2017. Mutant Pfmdr1-86Y decreased across years from 74.8% in 1996 to zero in 2017, mutant Pfmdr1-184F and wild Pfmdr1-D1246 increased from 17.9% to 58.9% in 2007 to 55.9% and 90.1% in 2017, respectively. Pfmdr1 haplotype N86F184S1034N1042D1246 increased from 11.0% in 2007 to 49.6% in 2017. No resistant mutations in Pfk13 were found. Prevalence of Pfdhps-436H was lower while prevalence of Pfcrt-76 T was higher in mosquitoes than in human blood samples. CONCLUSION This study showed an increased prevalence of dhfr/dhps resistant markers over 20 years with the emergence of Pfdhps-436H mutant a decade ago in Asembo. The reversal of Pfcrt from CQ-resistant to CQ-sensitive genotype occurred following 19 years of CQ withdrawal. No Pfk13 markers associated with artemisinin resistance were detected, but the increased haplotype of Pfmdr1 N86F184S1034N1042D1246 was observed. The differences in prevalence of Pfdhps-436H and Pfcrt-76 T SNPs between two hosts and the role of mosquitoes in the transmission of drug resistant parasites require further investigation.
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Kumar S, Li X, McDew-White M, Reyes A, Delgado E, Sayeed A, Haile MT, Abatiyow BA, Kennedy SY, Camargo N, Checkley LA, Brenneman KV, Button-Simons KA, Duraisingh MT, Cheeseman IH, Kappe SHI, Nosten F, Ferdig MT, Vaughan AM, Anderson TJC. A Malaria Parasite Cross Reveals Genetic Determinants of Plasmodium falciparum Growth in Different Culture Media. Front Cell Infect Microbiol 2022; 12:878496. [PMID: 35711667 PMCID: PMC9197316 DOI: 10.3389/fcimb.2022.878496] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/28/2022] [Indexed: 12/21/2022] Open
Abstract
What genes determine in vitro growth and nutrient utilization in asexual blood-stage malaria parasites? Competition experiments between NF54, clone 3D7, a lab-adapted African parasite, and a recently isolated Asian parasite (NHP4026) reveal contrasting outcomes in different media: 3D7 outcompetes NHP4026 in media containing human serum, while NHP4026 outcompetes 3D7 in media containing AlbuMAX, a commercial lipid-rich bovine serum formulation. To determine the basis for this polymorphism, we conducted parasite genetic crosses using humanized mice and compared genome-wide allele frequency changes in three independent progeny populations cultured in media containing human serum or AlbuMAX. This bulk segregant analysis detected three quantitative trait loci (QTL) regions [on chromosome (chr) 2 containing aspartate transaminase AST; chr 13 containing EBA-140; and chr 14 containing cysteine protease ATG4] linked with differential growth in serum or AlbuMAX in each of the three independent progeny pools. Selection driving differential growth was strong (s = 0.10 – 0.23 per 48-hour lifecycle). We conducted validation experiments for the strongest QTL on chr 13: competition experiments between ΔEBA-140 and 3D7 wildtype parasites showed fitness reversals in the two medium types as seen in the parental parasites, validating this locus as the causative gene. These results (i) demonstrate the effectiveness of bulk segregant analysis for dissecting fitness traits in P. falciparum genetic crosses, and (ii) reveal intimate links between red blood cell invasion and nutrient composition of growth media. Use of parasite crosses combined with bulk segregant analysis will allow systematic dissection of key nutrient acquisition/metabolism and red blood cell invasion pathways in P. falciparum.
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Affiliation(s)
- Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Xue Li
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Marina McDew-White
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Ann Reyes
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Elizabeth Delgado
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Abeer Sayeed
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Meseret T. Haile
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Biley A. Abatiyow
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Spencer Y. Kennedy
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Nelly Camargo
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Lisa A. Checkley
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States
| | - Katelyn V. Brenneman
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States
| | - Katrina A. Button-Simons
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States
| | - Manoj T. Duraisingh
- Immunology and Infectious Diseases Department, Harvard T.H. Chan School of Public Health, Boston, MA, United States
| | - Ian H. Cheeseman
- Program in Host Pathogen Interactions, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Stefan H. I. Kappe
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
- Department of Pediatrics, University of Washington, Seattle, WA, United States
| | - François Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research building, University of Oxford, Oxford, United Kingdom
| | - Michael T. Ferdig
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States
| | - Ashley M. Vaughan
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
- Department of Pediatrics, University of Washington, Seattle, WA, United States
- *Correspondence: Ashley M. Vaughan, ; Tim J. C. Anderson,
| | - Tim J. C. Anderson
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
- *Correspondence: Ashley M. Vaughan, ; Tim J. C. Anderson,
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Assessing the Roles of Molecular Markers of Antimalarial Drug Resistance and the Host Pharmacogenetics in Drug-Resistant Malaria. J Trop Med 2022; 2022:3492696. [PMID: 35620049 PMCID: PMC9129956 DOI: 10.1155/2022/3492696] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/17/2022] [Accepted: 04/29/2022] [Indexed: 01/11/2023] Open
Abstract
Malaria caused by the Plasmodium parasites is a major public health concern in malaria-endemic regions with P. falciparum causing the most severe form of the disease. The use of antimalarial drugs for the management of the disease proves to be one of the best methods to manage the disease. Unfortunately, P. falciparum has developed resistance to almost all the current in-use antimalarial drugs. Parasite development of resistance is primarily caused by both parasite and host genetic factors. The parasite genetic factors involve undergoing mutation in the drug target sites or increasing the drug target gene copy number to prevent the intended action of the antimalarial drugs. The host pharmacogenetic factors which determine how a particular antimalarial drug is metabolized could result in variations of drug plasma concentration and consequently contribute to variable treatment outcomes and the emergence or propagation of resistant parasites. Since both host and parasite genomes play a role in antimalarial drug action, a key question often asked is, “which of the two strongly drives or controls antimalarial drug resistance?” A major finding in our recent study published in the Malaria Journal indicates that the parasite's genetic factors rather than the host are likely to energize resistance to an antimalarial drug. However, others have reported contrary findings suggesting that the host genetic factors are the force behind resistance to antimalarial drugs. To bring clarity to these observations, there is the need for deciphering the major driving force behind antimalarial drug resistance through optimized strategies aimed at alleviating the phenomenon. In this direction, literature was systematically reviewed to establish the role and importance of each of the two factors aforementioned in the etiology of drug-resistant malaria. Using Internet search engines such as Pubmed and Google, we looked for terms likely to give the desired information which we herein present. We then went ahead to leverage the obtained information to discuss the globally avid aim of combating antimalarial drug resistance.
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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] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Plowe CV. Malaria chemoprevention and drug resistance: a review of the literature and policy implications. Malar J 2022; 21:104. [PMID: 35331231 PMCID: PMC8943514 DOI: 10.1186/s12936-022-04115-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/03/2022] [Indexed: 01/19/2023] Open
Abstract
Chemoprevention strategies reduce malaria disease and death, but the efficacy of anti-malarial drugs used for chemoprevention is perennially threatened by drug resistance. This review examines the current impact of chemoprevention on the emergence and spread of drug resistant malaria, and the impact of drug resistance on the efficacy of each of the chemoprevention strategies currently recommended by the World Health Organization, namely, intermittent preventive treatment in pregnancy (IPTp); intermittent preventive treatment in infants (IPTi); seasonal malaria chemoprevention (SMC); and mass drug administration (MDA) for the reduction of disease burden in emergency situations. While the use of drugs to prevent malaria often results in increased prevalence of genetic mutations associated with resistance, malaria chemoprevention interventions do not inevitably lead to meaningful increases in resistance, and even high rates of resistance do not necessarily impair chemoprevention efficacy. At the same time, it can reasonably be anticipated that, over time, as drugs are widely used, resistance will generally increase and efficacy will eventually be lost. Decisions about whether, where and when chemoprevention strategies should be deployed or changed will continue to need to be made on the basis of imperfect evidence, but practical considerations such as prevalence patterns of resistance markers can help guide policy recommendations.
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Targeted Amplicon Deep Sequencing for Monitoring Antimalarial Resistance Markers in Western Kenya. Antimicrob Agents Chemother 2022; 66:e0194521. [PMID: 35266823 PMCID: PMC9017353 DOI: 10.1128/aac.01945-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Molecular surveillance of Plasmodium falciparum parasites is important to track emerging and new mutations and trends in established mutations and should serve as an early warning system for antimalarial resistance. Dried blood spots were obtained from a Plasmodium falciparum malaria survey in school children conducted across eight counties in western Kenya in 2019. Real-time PCR identified 500 P. falciparum-positive samples that were amplified at five drug resistance loci for targeted amplicon deep sequencing (TADS). The absence of important kelch 13 mutations was similar to previous findings in Kenya pre-2019, and low-frequency mutations were observed in codons 569 and 578. The chloroquine resistance transporter gene codons 76 and 145 were wild type, indicating that the parasites were chloroquine and piperaquine sensitive, respectively. The multidrug resistance gene 1 haplotypes based on codons 86, 184, and 199 were predominantly present in mixed infections with haplotypes NYT and NFT, driven by the absence of chloroquine pressure and the use of lumefantrine, respectively. The sulfadoxine-pyrimethamine resistance profile was a “superresistant” combination of triple mutations in both Pfdhfr (51I 59R 108N) and Pfdhps (436H 437G 540E), rendering sulfadoxine-pyrimethamine ineffective. TADS highlighted the low-frequency variants, allowing the early identification of new mutations, Pfmdr1 codon 199S and Pfdhfr codon 85I and emerging 164L mutations. The added value of TADS is its accuracy in identifying mixed-genotype infections and for high-throughput monitoring of antimalarial resistance markers.
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Chaniad P, Phuwajaroanpong A, Techarang T, Horata N, Chukaew A, Punsawad C. Evaluation of the antimalarial activity and toxicity of Mahanil-Tang-Thong formulation and its plant ingredients. BMC Complement Med Ther 2022; 22:51. [PMID: 35219319 PMCID: PMC8882293 DOI: 10.1186/s12906-022-03531-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 02/14/2022] [Indexed: 12/22/2022] Open
Abstract
Abstract
Background
Novel potent antimalarial agents are urgently needed to overcome the problem of drug-resistant malaria. Herbal treatments are of interest because plants are the source of many pharmaceutical compounds. The Mahanil-Tang-Thong formulation is a Thai herbal formulation in the national list of essential medicines and is used for the treatment of fever. Therefore, this study aimed to evaluate the antimalarial activity of medicinal plants in the Mahanil-Tang-Thong formulation.
Methods
Nine medicinal plant ingredients of the Mahanil-Tang-Thong formulation were used in this study. Aqueous and ethanolic extracts of all the plants were analyzed for their phytochemical constituents. All the extracts were used to investigate the in vitro antimalarial activity against Plasmodium falciparum K1 (chloroquine-resistant strain) by using the lactate dehydrogenase (pLDH) method and cytotoxicity in Vero cells by using the 3-(4,5-dimethylthiazol2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Additionally, an extract with potent in vitro antimalarial activity and no toxicity was selected to determine the in vivo antimalarial activity with Peters’ 4-day suppressive test against the Plasmodium berghei ANKA strain. Acute toxicity was evaluated in mice for 14 days after the administration of a single oral dose of 2000 mg/kg.
Results
This study revealed that ethanolic extracts of Sapindus rarak DC., Tectona grandis L.f., Myristica fragrans Houtt. and Dracaena loureiri Gagnep. exhibited potent antimalarial activity, with half-maximal inhibitory concentration (IC50) values of 2.46, 3.21, 8.87 and 10.47 μg/ml, respectively, while the ethanolic of the formulation exhibited moderate activity with an IC50 value of 37.63 μg/ml and its aqueous extract had no activity (IC50 = 100.49 μg/ml). According to the in vitro study, the ethanolic wood extract of M. fragrans was selected for further investigation in an in vivo mouse model. M. fragrans extract at doses of 200, 400, and 600 mg/kg body weight produced a dose-dependent reduction in parasitemia by 8.59, 31.00, and 52.58%, respectively. No toxic effects were observed at a single oral dose of 2000 mg/kg body weight.
Conclusion
This study demonstrates that M. fragrans is a potential candidate for the development of antimalarial agents.
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Omedo I, Bartilol B, Kimani D, Gonçalves S, Drury E, Rono MK, Abdi AI, Almagro-Garcia J, Amato R, Pearson RD, Ochola-Oyier LI, Kwiatkowski D, Bejon P. Spatio-temporal distribution of antimalarial drug resistant gene mutations in a Plasmodium falciparum parasite population from Kilifi, Kenya: A 25-year retrospective study. Wellcome Open Res 2022. [DOI: 10.12688/wellcomeopenres.17656.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Antimalarial drug resistance is a major obstacle to sustainable malaria control. Here we use amplicon sequencing to describe molecular markers of drug resistance in Plasmodium falciparum parasites from Kilifi county in the coastal region of Kenya over a 25-year period. Methods: We performed P. falciparum amplicon sequencing on 1162 malaria-infected blood samples collected between 1994 and 2018 to identify markers of antimalarial drug resistance in the Pfcrt, Pfdhfr, Pfdhps, Pfmdr1, Pfexo, Pfkelch13, plasmepsin 2/3, Pfarps10, Pffd, and Pfmdr2 genes. We further interrogated parasite population structure using a genetic barcode of 101 drug resistance-unrelated single nucleotide polymorphisms (SNPs) distributed across the genomes of 1245 P. falciparum parasites. Results: Two major changes occurred in the parasite population over the 25 years studied. In 1994, approximately 75% of parasites carried the marker of chloroquine resistance, CVIET. This increased to 100% in 1999 and then declined steadily, reaching 6.7% in 2018. Conversely, the quintuple mutation form of sulfadoxine-pyrimethamine resistance increased from 16.7% in 1994 to 83.6% in 2018. Several non-synonymous mutations were identified in the Kelch13 gene, although none of them are currently associated with artemisinin resistance. We observed a temporal increase in the Pfmdr1 NFD haplotype associated with lumefantrine resistance, but observed no evidence of piperaquine resistance. SNPs in other parts of the genome showed no significant temporal changes despite the marked changes in drug resistance loci over this period. Conclusions: We identified substantial changes in molecular markers of P. falciparum drug resistance over 25 years in coastal Kenya, but no associated changes in the parasite population structure.
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Nate Z, Gill AA, Chauhan R, Karpoormath R. A review on recent progress in electrochemical detection of antimalarial drugs. RESULTS IN CHEMISTRY 2022. [DOI: 10.1016/j.rechem.2022.100494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Cannabis sativa L. chemical compositions as potential plasmodium falciparum dihydrofolate reductase-thymidinesynthase enzyme inhibitors: An in silico study for drug development. OPEN CHEM 2021. [DOI: 10.1515/chem-2021-0102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
This study contributes to anti-malarial research effort by conducting in silico assessment of 125 compounds originated from Cannabis sativa L. against plasmodium falciparum dihydrofolate reductase-thymidinesynthase (pfDHFR-TS) enzyme for potential inhibition activity. Drug-like and pharmacokinetic criteria were used to assess the drug-like properties of the studied compounds. AutoDock4.2.6 and AutoDock Vina software were used to calculate the possible binding pose of the studied compounds to pfDHFR-TS enzyme. The docking procedure was validated using two known inhibitors cycloguanil and WR99210. 65 out of 125 compounds violated no more than 2 of Lipinski’s rule of five and were sorted out as favorable for drug development. Amongst these 65 compounds, pharmacokinetic properties and toxicity evaluation identified 60 compounds that meet the criteria of drug-like properties and were subjected to further docking studies. Docking outcomes identified 10 compounds including compounds 4, 9, 19, 22, 23, 25, 30, 42, 43, and 59 as potential candidates for inhibiting the function of pfDHFR-TS at the active site through hydrogen bonds with Ile14, Asp54, and Ile 164 residues. Compound 9 is considered as the top “hit” with docking energy far more exceeding those of the standard compounds. High correlation coefficient between the docking energy of AutoDock4.2.6 and AutoDock Vina was recorded with the value of R
2 = 0.74.
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Comparative Analysis of Plasmodium falciparum Genotyping via SNP Detection, Microsatellite Profiling, and Whole-Genome Sequencing. Antimicrob Agents Chemother 2021; 66:e0116321. [PMID: 34694871 PMCID: PMC8765236 DOI: 10.1128/aac.01163-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Research efforts to combat antimalarial drug resistance rely on quick, robust, and sensitive methods to genetically characterize Plasmodium falciparum parasites. We developed a single-nucleotide polymorphism (SNP)-based genotyping method that can assess 33 drug resistance-conferring SNPs in dhfr, dhps, pfmdr1, pfcrt, and k13 in nine PCRs, performed directly from P. falciparum cultures or infected blood. We also optimized multiplexed fragment analysis and gel electrophoresis-based microsatellite typing methods using a set of five markers that can distinguish 12 laboratory strains of diverse geographical and temporal origin. We demonstrate how these methods can be applied to screen for the multidrug-resistant KEL1/PLA1/PfPailin (KelPP) lineage that has been sweeping across the Greater Mekong Subregion, verify parasite in vitro SNP-editing, identify novel recombinant genetic cross progeny, or cluster strains to infer their geographical origins. Results were compared with Illumina-based whole-genome sequence analysis that provides the most detailed sequence information but is cost-prohibitive. These adaptable, simple, and inexpensive methods can be easily implemented into routine genotyping of P. falciparum parasites in both laboratory and field settings.
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Efforts Made to Eliminate Drug-Resistant Malaria and Its Challenges. BIOMED RESEARCH INTERNATIONAL 2021; 2021:5539544. [PMID: 34497848 PMCID: PMC8421183 DOI: 10.1155/2021/5539544] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 08/09/2021] [Indexed: 01/01/2023]
Abstract
Since 2000, a good deal of progress has been made in malaria control. However, there is still an unacceptably high burden of the disease and numerous challenges limiting advancement towards its elimination and ultimate eradication. Among the challenges is the antimalarial drug resistance, which has been documented for almost all antimalarial drugs in current use. As a result, the malaria research community is working on the modification of existing treatments as well as the discovery and development of new drugs to counter the resistance challenges. To this effect, many products are in the pipeline and expected to be marketed soon. In addition to drug and vaccine development, mass drug administration (MDA) is under scientific scrutiny as an important strategy for effective utilization of the developed products. This review discusses the challenges related to malaria elimination, ongoing approaches to tackle the impact of drug-resistant malaria, and upcoming antimalarial drugs.
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Kreutzfeld O, Tumwebaze PK, Byaruhanga O, Katairo T, Okitwi M, Orena S, Rasmussen SA, Legac J, Conrad MD, Nsobya SL, Aydemir O, Bailey JA, Duffey M, Cooper RA, Rosenthal PJ. Decreased Susceptibility to Dihydrofolate Reductase Inhibitors Associated With Genetic Polymorphisms in Ugandan Plasmodium falciparum Isolates. J Infect Dis 2021; 225:696-704. [PMID: 34460932 PMCID: PMC8844592 DOI: 10.1093/infdis/jiab435] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 08/27/2021] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The Plasmodium falciparum dihydrofolate reductase (PfDHFR) inhibitors pyrimethamine and cycloguanil (the active metabolite of proguanil) have important roles in malaria chemoprevention, but drug resistance challenges their efficacies. A new compound, P218, was designed to overcome resistance, but drug-susceptibility data for P falciparum field isolates are limited. METHODS We studied ex vivo PfDHFR inhibitor susceptibilities of 559 isolates from Tororo and Busia districts, Uganda, from 2016 to 2020, sequenced 383 isolates, and assessed associations between genotypes and drug-susceptibility phenotypes. RESULTS Median half-maximal inhibitory concentrations (IC50s) were 42 100 nM for pyrimethamine, 1200 nM for cycloguanil, 13000 nM for proguanil, and 0.6 nM for P218. Among sequenced isolates, 3 PfDHFR mutations, 51I (100%), 59R (93.7%), and 108N (100%), were very common, as previously seen in Uganda, and another mutation, 164L (12.8%), had moderate prevalence. Increasing numbers of mutations were associated with decreasing susceptibility to pyrimethamine, cycloguanil, and P218, but not proguanil, which does not act directly against PfDHFR. Differences in P218 susceptibilities were modest, with median IC50s of 1.4 nM for parasites with mixed genotype at position 164 and 5.7 nM for pure quadruple mutant (51I/59R/108N/164L) parasites. CONCLUSIONS Resistance-mediating PfDHFR mutations were common in Ugandan isolates, but P218 retained excellent activity against mutant parasites.
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Affiliation(s)
| | | | | | - Thomas Katairo
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Martin Okitwi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Stephen Orena
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Jennifer Legac
- University of California, San Francisco, California, USA
| | | | - Sam L Nsobya
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | | | | | - Roland A Cooper
- Dominican University of California, San Rafael, California, USA
| | - Philip J Rosenthal
- Correspondence: Philip J. Rosenthal, MD, Department of Medicine, University of California, Box 0811, San Francisco, CA 94143 USA ()
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Tuedom AGB, Sarah-Matio EM, Moukoko CEE, Feufack-Donfack BL, Maffo CN, Bayibeki AN, Awono-Ambene HP, Ayong L, Berry A, Abate L, Morlais I, Nsango SE. Antimalarial drug resistance in the Central and Adamawa regions of Cameroon: Prevalence of mutations in P. falciparum crt, Pfmdr1, Pfdhfr and Pfdhps genes. PLoS One 2021; 16:e0256343. [PMID: 34411157 PMCID: PMC8376100 DOI: 10.1371/journal.pone.0256343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 08/05/2021] [Indexed: 11/19/2022] Open
Abstract
The spread of Plasmodium falciparum resistant parasites remains one of the major challenges for malaria control and elimination in Sub Saharan Africa. Monitoring of molecular markers conferring resistance to different antimalarials is important to track the spread of resistant parasites and to optimize the therapeutic lifespan of current drugs. This study aimed to evaluate the prevalence of known mutations in the drug resistance genes Pfcrt, Pfmdr1, Pfdhfr and Pfdhps in two different epidemiological settings in Cameroon. Dried blood spots collected in 2018 and 2019 from asymptomatic individuals were used for DNA extraction and then the Plasmodium infection status was determined byPCR. Detection of SNPs was performed by nested PCR followed by allele-specific restriction analysis (ASRA). The prevalence of each genotype was compared between sites using the Chi square and Fisher’s exact tests. A high prevalence of the Pfcrt K76 wild type allele was found in both sites (88.5 and 62.29% respectively; P< 0,0001). The prevalence of Pfmdr1 mutations 86Y and 1246Y was respectively 55.83 and 1.45% in Mfou and 45.87 and 5.97% in Tibati, with significant difference between the studied areas (P<0.0001). Overall, the Pfdhfr triple-mutant genotype (51I/59R/108N) was highly prevalent (> 96%), however no SNP was detected at codon 164. In Pfdhps, the prevalence of the 437G mutation reached (90%) and was at higher frequency in Mfou (P< 0.0001). Overall, the Pfdhps mutations 540E and 581G were less common (0.33 and 3.26%, respectively). The quadruple resistant genotype (Pfdhfr 51I/59R/108N+Pfdhp437G) was found almost 90% of the samples. The wild-type genotype (Pfdhfr N51/C59/S108/164I+Pfdhps A437/K540/A581) was never identified and the sextuple mutant (Pfdhfr 51I/59R/108N+Pfdhp437G/540E/581G), kwon as super resistant appeared in two samples from Tibati. These findings demonstrate declining trends in the prevalence of mutations conferring resistance to 4-aminoquinolines, especially to chloroquine. However, a high level of mutations in P. falciparum genes related to SP resistance was detected and this raises concerns about the future efficacy of IPTp-SP and SMC in Cameroon.
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Affiliation(s)
- Aline Gaelle Bouopda Tuedom
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroun
| | - Elangwe Milo Sarah-Matio
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroun
- UMR MIVEGEC, IRD, CNRS, Institut de Recherche pour le Développement, Université Montpellier, Montpellier Cedex, France
| | - Carole Else Eboumbou Moukoko
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroun
| | - Brice Lionel Feufack-Donfack
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroun
- CNRS UPR9022, INSERM U963, Strasbourg, France
| | - Christelle Ngou Maffo
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroun
- UMR MIVEGEC, IRD, CNRS, Institut de Recherche pour le Développement, Université Montpellier, Montpellier Cedex, France
| | - Albert Ngano Bayibeki
- Université Catholique d’Afrique Centrale, Yaoundé-Campus Messa Cameroun, Yaoundé, Cameroun
| | - Hermann Parfait Awono-Ambene
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroun
| | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroun
| | - Antoine Berry
- Service de Parasitologie-Mycologie, Centre Hospitalier Universitaire de Toulouse et UMR152 UPS-IRD, Université de Toulouse, Toulouse, France
| | - Luc Abate
- UMR MIVEGEC, IRD, CNRS, Institut de Recherche pour le Développement, Université Montpellier, Montpellier Cedex, France
| | - Isabelle Morlais
- UMR MIVEGEC, IRD, CNRS, Institut de Recherche pour le Développement, Université Montpellier, Montpellier Cedex, France
| | - Sandrine Eveline Nsango
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroun
- * E-mail: ,
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Abstract
Although the last two decades have seen a substantial decline in malaria incidence and mortality due to the use of insecticide-treated bed nets and artemisinin combination therapy, the threat of drug resistance is a constant obstacle to sustainable malaria control. Given that patients can die quickly from this disease, public health officials and doctors need to understand whether drug resistance exists in the parasite population, as well as how prevalent it is so they can make informed decisions about treatment. As testing for drug efficacy before providing treatment to malaria patients is impractical, researchers need molecular markers of resistance that can be more readily tracked in parasite populations. To this end, much work has been done to unravel the genetic underpinnings of drug resistance in Plasmodium falciparum. The aim of this review is to provide a broad overview of common genomic approaches that have been used to discover the alleles that drive drug response phenotypes in the most lethal human malaria parasite.
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Affiliation(s)
- Frances Rocamora
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Elizabeth A Winzeler
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
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Rogier E, Herman C, Huber CS, Hamre KES, Pierre B, Mace KE, Présumé J, Mondélus G, Romilus I, Elismé T, Eisele TP, Druetz T, Existe A, Boncy J, Lemoine JF, Udhayakumar V, Chang MA. Nationwide Monitoring for Plasmodium falciparum Drug-Resistance Alleles to Chloroquine, Sulfadoxine, and Pyrimethamine, Haiti, 2016-2017. Emerg Infect Dis 2021; 26:902-909. [PMID: 32310062 PMCID: PMC7181918 DOI: 10.3201/eid2605.190556] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Haiti is striving for zero local malaria transmission by the year 2025. Chloroquine remains the first-line treatment, and sulfadoxine/pyrimethamine (SP) has been used for mass drug-administration pilot programs. In March 2016, nationwide molecular surveillance was initiated to assess molecular resistance signatures for chloroquine and SP. For 778 samples collected through December 2017, we used Sanger sequencing to investigate putative resistance markers to chloroquine (Pfcrt codons 72, 74, 75, and 76), sulfadoxine (Pfdhps codons 436, 437, 540, 581, 613), and pyrimethamine (Pfdhfr codons 50, 51, 59, 108, 164). No parasites harbored Pfcrt point mutations. Prevalence of the Pfdhfr S108N single mutation was 47%, and we found the triple mutant Pfdhfr haplotype (108N, 51I, and 59R) in a single isolate. We observed no Pfdhps variants except in 1 isolate (A437G mutation). These data confirm the lack of highly resistant chloroquine and SP alleles in Haiti and support the continued use of chloroquine and SP.
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Chaturvedi R, Chhibber-Goel J, Verma I, Gopinathan S, Parvez S, Sharma A. Geographical spread and structural basis of sulfadoxine-pyrimethamine drug-resistant malaria parasites. Int J Parasitol 2021; 51:505-525. [PMID: 33775670 DOI: 10.1016/j.ijpara.2020.12.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 11/24/2020] [Accepted: 12/03/2020] [Indexed: 12/22/2022]
Abstract
The global spread of sulfadoxine (Sdx, S) and pyrimethamine (Pyr, P) resistance is attributed to increasing number of mutations in DHPS and DHFR enzymes encoded by malaria parasites. The association between drug resistance mutations and SP efficacy is complex. Here we provide an overview of the geographical spread of SP resistance mutations in Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) encoded dhps and dhfr genes. In addition, we have collated the mutation data and mapped it on to the three-dimensional structures of DHPS and DHFR which have become available. Data from genomic databases and 286 studies were collated to provide a comprehensive landscape of mutational data from 2005 to 2019. Our analyses show that the Pyr-resistant double mutations are widespread in Pf/PvDHFR (P. falciparum ∼61% in Asia and the Middle East, and in the Indian sub-continent; in P. vivax ∼33% globally) with triple mutations prevailing in Africa (∼66%) and South America (∼33%). For PfDHPS, triple mutations dominate South America (∼44%), Asia and the Middle East (∼34%) and the Indian sub-continent (∼27%), while single mutations are widespread in Africa (∼45%). Contrary to the status for P. falciparum, Sdx-resistant single point mutations in PvDHPS dominate globally. Alarmingly, highly resistant quintuple and sextuple mutations are rising in Africa (PfDHFR-DHPS) and Asia (Pf/PvDHFR-DHPS). Structural analyses of DHFR and DHPS proteins in complexes with substrates/drugs have revealed that resistance mutations map proximal to Sdx and Pyr binding sites. Thus new studies can focus on discovery of novel inhibitors that target the non-substrate binding grooves in these two validated malaria parasite drug targets.
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Affiliation(s)
- Rini Chaturvedi
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India; Department of Toxicology, Jamia Hamdard, New Delhi, India
| | - Jyoti Chhibber-Goel
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Ishika Verma
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Sreehari Gopinathan
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Suhel Parvez
- Department of Toxicology, Jamia Hamdard, New Delhi, India
| | - Amit Sharma
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India; National Institute of Malaria Research, Dwarka, New Delhi, India.
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Duffey M, Blasco B, Burrows JN, Wells TNC, Fidock DA, Leroy D. Assessing risks of Plasmodium falciparum resistance to select next-generation antimalarials. Trends Parasitol 2021; 37:709-721. [PMID: 34001441 DOI: 10.1016/j.pt.2021.04.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/01/2021] [Accepted: 04/08/2021] [Indexed: 02/07/2023]
Abstract
Strategies to counteract or prevent emerging drug resistance are crucial for the design of next-generation antimalarials. In the past, resistant parasites were generally identified following treatment failures in patients, and compounds would have to be abandoned late in development. An early understanding of how candidate therapeutics lose efficacy as parasites evolve resistance is important to facilitate drug design and improve resistance detection and monitoring up to the postregistration phase. We describe a new strategy to assess resistance to antimalarial compounds as early as possible in preclinical development by leveraging tools to define the Plasmodium falciparum resistome, predict potential resistance risks of clinical failure for candidate therapeutics, and inform decisions to guide antimalarial drug development.
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Affiliation(s)
| | - Benjamin Blasco
- Medicines for Malaria Venture, Geneva, Switzerland; Global Antibiotic Research and Development Partnership, Geneva, Switzerland
| | | | | | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA; Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland.
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43
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Roberds A, Ferraro E, Luckhart S, Stewart VA. HIV-1 Impact on Malaria Transmission: A Complex and Relevant Global Health Concern. Front Cell Infect Microbiol 2021; 11:656938. [PMID: 33912477 PMCID: PMC8071860 DOI: 10.3389/fcimb.2021.656938] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/18/2021] [Indexed: 02/05/2023] Open
Abstract
Malaria/HIV-1 co-infection has become a significant public health problem in the tropics where there is geographical overlap of the two diseases. It is well described that co-infection impacts clinical progression of both diseases; however, less is known about the impact of co-infection on disease transmission. Malaria transmission is dependent upon multiple critical factors, one of which is the presence and viability of the sexual-stage gametocyte. In this review, we summarize evidence surrounding gametocyte production in Plasmodium falciparum and the development factors and the consequential impact that HIV-1 has on malaria parasite transmission. Epidemiological and clinical evidence surrounding anemia, immune dysregulation, and chemotherapy as it pertains to co-infection and gametocyte transmission are reviewed. We discuss significant gaps in understanding that are often due to the biological complexities of both diseases as well as the lack of entomological data necessary to define transmission success. In particular, we highlight special epidemiological populations, such as co-infected asymptomatic gametocyte carriers, and the unique role these populations have in a future focused on malaria elimination and eradication.
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Affiliation(s)
- Ashleigh Roberds
- Department of Preventive Medicine and Biostatistics, Division of Tropical Public Health, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Emily Ferraro
- Department of Preventive Medicine and Biostatistics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology and Nematology, Department of Biological Sciences, College of Agricultural and Life Sciences, University of Idaho, Moscow, ID, United States
| | - V Ann Stewart
- Department of Preventive Medicine and Biostatistics, Division of Tropical Public Health, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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44
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Ebel ER, Reis F, Petrov DA, Beleza S. Historical trends and new surveillance of Plasmodium falciparum drug resistance markers in Angola. Malar J 2021; 20:175. [PMID: 33827587 PMCID: PMC8028775 DOI: 10.1186/s12936-021-03713-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 03/25/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Plasmodium falciparum resistance to chloroquine (CQ) and sulfadoxine-pyrimethamine (SP) has historically posed a major threat to malaria control throughout the world. The country of Angola officially replaced CQ with artemisinin-based combination therapy (ACT) as a first-line treatment in 2006, but malaria cases and deaths have recently been rising. Many classic resistance mutations are relevant for the efficacy of currently available drugs, making it important to continue monitoring their frequency in Angola. METHODS Plasmodium falciparum DNA was sampled from the blood of 50 hospital patients in Cabinda, Angola from October-December of 2018. Each infection was genotyped for 13 alleles in the genes crt, mdr1, dhps, dhfr, and kelch13, which are collectively involved in resistance to six common anti-malarials. To compare frequency patterns over time, P. falciparum genotype data were also collated from studies published from across Angola in the last two decades. RESULTS The two most important alleles for CQ resistance, crt 76T and mdr1 86Y, were found at respective frequencies of 71.4% and 6.5%. Historical data suggest that mdr1 N86 has been steadily replacing 86Y throughout Angola in the last decade, while the frequency of crt 76T has been more variable across studies. Over a third of new samples from Cabinda were 'quintuple mutants' for SP resistance in dhfr/dhps, with a sixth mutation at dhps A581G present at 9.6% frequency. The markers dhfr 51I, dhfr 108N, and dhps 437G have been nearly fixed in Angola since the early 2000s, whereas dhfr 59R may have risen to high frequency more recently. Finally, no non-synonymous polymorphisms were detected in kelch13, which is involved in artemisinin resistance in Southeast Asia. CONCLUSIONS Genetic markers of P. falciparum resistance to CQ are likely declining in frequency in Angola, consistent with the official discontinuation of CQ in 2006. The high frequency of multiple genetic markers of SP resistance is consistent with the continued public and private use of SP. In the future, more complete haplotype data from mdr1, dhfr, and dhps will be critical for understanding the changing efficacy of multiple anti-malarial drugs. These data can be used to support effective drug policy decisions in Angola.
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Affiliation(s)
- Emily R Ebel
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
- Department of Pediatrics, Infectious Disease, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Fátima Reis
- Hospital Regional de Cabinda, C5QW+XP, Cabinda, Angola
| | - Dmitri A Petrov
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Sandra Beleza
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK.
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45
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Wróbel A, Drozdowska D. Recent Design and Structure-Activity Relationship Studies on the Modifications of DHFR Inhibitors as Anticancer Agents. Curr Med Chem 2021; 28:910-939. [PMID: 31622199 DOI: 10.2174/0929867326666191016151018] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Dihydrofolate reductase (DHFR) has been known for decades as a molecular target for antibacterial, antifungal and anti-malarial treatments. This enzyme is becoming increasingly important in the design of new anticancer drugs, which is confirmed by numerous studies including modelling, synthesis and in vitro biological research. This review aims to present and discuss some remarkable recent advances in the research of new DHFR inhibitors with potential anticancer activity. METHODS The scientific literature of the last decade on the different types of DHFR inhibitors has been searched. The studies on design, synthesis and investigation structure-activity relationships were summarized and divided into several subsections depending on the leading molecule and its structural modification. Various methods of synthesis, potential anticancer activity and possible practical applications as DHFR inhibitors of new chemical compounds were described and discussed. RESULTS This review presents the current state of knowledge on the modification of known DHFR inhibitors and the structures and searches for about eighty new molecules, designed as potential anticancer drugs. In addition, DHFR inhibitors acting on thymidylate synthase (TS), carbon anhydrase (CA) and even DNA-binding are presented in this paper. CONCLUSION Thorough physicochemical characterization and biological investigations highlight the structure-activity relationship of DHFR inhibitors. This will enable even better design and synthesis of active compounds, which would have the expected mechanism of action and the desired activity.
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Affiliation(s)
- Agnieszka Wróbel
- Department of Organic Chemistry, Faculty of Pharmacy, Medical University, Białystok, Poland
| | - Danuta Drozdowska
- Department of Organic Chemistry, Faculty of Pharmacy, Medical University, Białystok, Poland
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46
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Arya A, Kojom Foko LP, Chaudhry S, Sharma A, Singh V. Artemisinin-based combination therapy (ACT) and drug resistance molecular markers: A systematic review of clinical studies from two malaria endemic regions - India and sub-Saharan Africa. Int J Parasitol Drugs Drug Resist 2021; 15:43-56. [PMID: 33556786 PMCID: PMC7887327 DOI: 10.1016/j.ijpddr.2020.11.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 11/23/2022]
Abstract
Artemisinin-based combination therapies (ACT) are currently used as a first-line malaria therapy in endemic countries worldwide. This systematic review aims at presenting the current scenario of drug resistance molecular markers, either selected or involved in treatment failures (TF) during in vivo ACT efficacy studies from sub-Saharan Africa (sSA) and India. Eight electronic databases were comprehensively used to search relevant articles and finally a total of 28 studies were included in the review, 21 from sSA and seven from India. On analysis, Artemether + lumefantrine (AL) and artesunate + sulfadoxine-pyrimethamine (AS + SP) are the main ACT in African and Indian regions with a 28-day efficacy range of 54.3-100% for AL and 63-100% for AS + SP respectively. It was observed that mutations in the Pfcrt (76T), Pfdhfr (51I, 59R, 108N), Pfdhps (437G) and Pfmdr1 (86Y, 184F, 1246Y) genes were involved in TF, which varied with respect to ACTs. Based on studies that have genotyped the Pfk13 gene, the reported TF cases, were mainly linked with mutations in genes associated with resistance to ACT partner drugs; indicating that the protection of the partner drug efficacy is crucial for maintaining the efficacy of ACT. This review reveals that ACT are largely efficacious in India and sSA despite the fact that some clinical efficacy and epidemiological studies have reported some validated mutations (i.e., 476I, 539T and 561H) in circulation in these two regions. Also, the role of PfATPase6 in ART resistance is controversial still, while P. falciparum plasmepsin 2 (Pfpm2) in piperaquine (PPQ) resistance and dihydroartemisinin (DHA) + PPQ failures is well documented in Southeast Asian countries but studied less in sSA. Hence, there is a need for continuous molecular surveillance of Pfk13 mutations for emergence of artemisinin (ART) resistance in these countries.
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Affiliation(s)
- Aditi Arya
- ICMR-National Institute of Malaria Research, New Delhi, India
| | | | - Shewta Chaudhry
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Amit Sharma
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Vineeta Singh
- ICMR-National Institute of Malaria Research, New Delhi, India.
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47
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Sibley CH. Prevalence of Antimalarial Resistance Mediators. J Infect Dis 2021; 223:927-929. [PMID: 33146721 DOI: 10.1093/infdis/jiaa688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 11/02/2020] [Indexed: 11/13/2022] Open
Affiliation(s)
- Carol Hopkins Sibley
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
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48
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Asua V, Conrad MD, Aydemir O, Duvalsaint M, Legac J, Duarte E, Tumwebaze P, Chin DM, Cooper RA, Yeka A, Kamya MR, Dorsey G, Nsobya SL, Bailey J, Rosenthal PJ. Changing Prevalence of Potential Mediators of Aminoquinoline, Antifolate, and Artemisinin Resistance Across Uganda. J Infect Dis 2021; 223:985-994. [PMID: 33146722 PMCID: PMC8006419 DOI: 10.1093/infdis/jiaa687] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/27/2020] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND In Uganda, artemether-lumefantrine is recommended for malaria treatment and sulfadoxine-pyrimethamine for chemoprevention during pregnancy, but drug resistance may limit efficacies. METHODS Genetic polymorphisms associated with sensitivities to key drugs were characterized in samples collected from 16 sites across Uganda in 2018 and 2019 by ligase detection reaction fluorescent microsphere, molecular inversion probe, dideoxy sequencing, and quantitative polymerase chain reaction assays. RESULTS Considering transporter polymorphisms associated with resistance to aminoquinolines, the prevalence of Plasmodium falciparum chloroquine resistance transporter (PfCRT) 76T decreased, but varied markedly between sites (0-46% in 2018; 0-23% in 2019); additional PfCRT polymorphisms and plasmepsin-2/3 amplifications associated elsewhere with resistance to piperaquine were not seen. For P. falciparum multidrug resistance protein 1, in 2019 the 86Y mutation was absent at all sites, the 1246Y mutation had prevalence ≤20% at 14 of 16 sites, and gene amplification was not seen. Considering mutations associated with high-level sulfadoxine-pyrimethamine resistance, prevalences of P. falciparum dihydrofolate reductase 164L (up to 80%) and dihydropteroate synthase 581G (up to 67%) were high at multiple sites. Considering P. falciparum kelch protein propeller domain mutations associated with artemisinin delayed clearance, prevalence of the 469Y and 675V mutations has increased at multiple sites in northern Uganda (up to 23% and 41%, respectively). CONCLUSIONS We demonstrate concerning spread of mutations that may limit efficacies of key antimalarial drugs.
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Affiliation(s)
- Victor Asua
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Melissa D Conrad
- University of California, San Francisco, San Francisco, California, USA
| | | | - Marvin Duvalsaint
- University of California, San Francisco, San Francisco, California, USA
| | - Jennifer Legac
- University of California, San Francisco, San Francisco, California, USA
| | - Elias Duarte
- University of California, San Francisco, San Francisco, California, USA
| | | | | | - Roland A Cooper
- Dominican University of California, San Rafael, California, USA
| | - Adoke Yeka
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Grant Dorsey
- University of California, San Francisco, San Francisco, California, USA
| | - Sam L Nsobya
- Infectious Diseases Research Collaboration, Kampala, Uganda
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Posayapisit N, Pengon J, Prommana P, Shoram M, Yuthavong Y, Uthaipibull C, Kamchonwongpaisan S, Jupatanakul N. Transgenic pyrimethamine-resistant plasmodium falciparum reveals transmission-blocking potency of P218, a novel antifolate candidate drug. Int J Parasitol 2021; 51:635-642. [PMID: 33713651 DOI: 10.1016/j.ijpara.2020.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 11/23/2020] [Accepted: 12/03/2020] [Indexed: 12/20/2022]
Abstract
Antimalarial drugs capable of targeting multiple parasite stages, particularly the transmissible stages, can be valuable tools for advancing the malaria elimination agenda. Current antifolate drugs such as pyrimethamine can inhibit replicative parasite stages in both humans and mosquitoes, but antifolate resistance remains a challenge. The lack of reliable gametocyte-producing, antifolate-resistant Plasmodium falciparum laboratory strain hinders the study of new antifolate compounds that can overcome antifolate resistance including development stages in the mosquito. We used clustered regularly interspaced short palindromic repeats-Cas9 genome editing to develop a transgenic gametocyte-producing strain of P. falciparum with quadruple mutations (N51I, C59R, S108N, I164L) in the dihydrofolate reductase (dhfr) gene, using NF54 as a parental strain. The transgenic parasites exhibited pyrimethamine resistance while maintaining their gametocyte-producing activity. We then demonstrated that pyrimethamine could no longer inhibit male gametocyte exflagellation in the transgenic parasite. In contrast, P218, the novel antifolate, designed to overcome antifolate resistance, potently inhibited exflagellation. The exflagellation IC50 of P218 was five times lower than the asexual stage half maximal inhibitory concentration (IC50), suggesting a strong barrier for transmission of P218-resistant parasites. The transgenic gametocyte-producing, pyrimethamine-resistant parasite is a robust system for evaluating novel antifolate compounds against non-asexual stage development.
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Affiliation(s)
- Navaporn Posayapisit
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani 12120, Thailand
| | - Jutharat Pengon
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani 12120, Thailand
| | - Parichat Prommana
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani 12120, Thailand
| | - Molnipha Shoram
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani 12120, Thailand
| | - Yongyuth Yuthavong
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani 12120, Thailand
| | - Chairat Uthaipibull
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani 12120, Thailand
| | | | - Natapong Jupatanakul
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani 12120, Thailand.
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50
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Svigel SS, Adeothy A, Kpemasse A, Houngbo E, Sianou A, Saliou R, Patton ME, Dagnon F, Halsey ES, Tchevoede A, Udhayakumar V, Lucchi NW. Low prevalence of highly sulfadoxine-resistant dihydropteroate synthase alleles in Plasmodium falciparum isolates in Benin. Malar J 2021; 20:72. [PMID: 33546703 PMCID: PMC7866691 DOI: 10.1186/s12936-021-03605-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/20/2021] [Accepted: 01/22/2021] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND In 2004, in response to high levels of treatment failure associated with sulfadoxine-pyrimethamine (SP) resistance, Benin changed its first-line malaria treatment from SP to artemisinin-based combination therapy for treatment of uncomplicated Plasmodium falciparum malaria. Resistance to SP is conferred by accumulation of single nucleotide polymorphisms (SNPs) in P. falciparum genes involved in folate metabolism, dihydrofolate reductase (Pfdhfr) and dihydropteroate synthase (Pfdhps), targeted by pyrimethamine and sulfadoxine, respectively. Because SP is still used for intermittent preventive treatment in pregnant women (IPTp) and seasonal malaria chemoprevention (SMCP) in Benin, the prevalence of Pfdhfr and Pfdhps SNPs in P. falciparum isolates collected in 2017 were investigated. METHODS This study was carried out in two sites where the transmission of P. falciparum malaria is hyper-endemic: Klouékanmey and Djougou. Blood samples were collected from 178 febrile children 6-59 months old with confirmed uncomplicated P. falciparum malaria and were genotyped for SNPs associated with SP resistance. RESULTS The Pfdhfr triple mutant IRN (N51I, C59R, and S108N) was the most prevalent (84.6%) haplotype and was commonly found with the Pfdhps single mutant A437G (50.5%) or with the Pfdhps double mutant S436A and A437G (33.7%). The quintuple mutant, Pfdhfr IRN/Pfdhps GE (A437G and K540E), was rarely observed (0.8%). The A581G and A613S mutant alleles were found in 2.6 and 3.9% of isolates, respectively. Six isolates (3.9%) were shown to harbour a mutation at codon I431V, recently identified in West African parasites. CONCLUSIONS This study showed that Pfdhfr triple IRN mutants are near fixation in this population and that the highly sulfadoxine-resistant Pfdhps alleles are not widespread in Benin. These data support the continued use of SP for chemoprevention in these study sites, which should be complemented by periodic nationwide molecular surveillance to detect emergence of resistant genotypes.
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Affiliation(s)
- Samaly Souza Svigel
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Adicath Adeothy
- National Malaria Control Programme, Ministry of Health, Cotonou, Benin.,John Snow, Inc. (JSI) , MA, Boston, USA
| | - Augustin Kpemasse
- National Malaria Control Programme, Ministry of Health, Cotonou, Benin
| | - Ernest Houngbo
- National Malaria Control Programme, Ministry of Health, Cotonou, Benin
| | - Antoine Sianou
- National Malaria Control Programme, Ministry of Health, Cotonou, Benin
| | - Ramani Saliou
- Accelerating the Reduction of Malaria Morbidity and Mortality Project (ARM3), Medical Care Development International, Cotonou, Benin
| | - Monica E Patton
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA.,U.S. President's Malaria Initiative, USAID, Cotonou, Benin
| | - Fortune Dagnon
- U.S. President's Malaria Initiative, USAID, Cotonou, Benin
| | - Eric S Halsey
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA.,U.S. President's Malaria Initiative, GA, Atlanta, USA
| | - Alexis Tchevoede
- National Malaria Control Programme, Ministry of Health, Cotonou, Benin
| | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Naomi W Lucchi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
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