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Phelan JE, Turkiewicz A, Manko E, Thorpe J, Vanheer LN, van de Vegte-Bolmer M, Ngoc NTH, Binh NTH, Thieu NQ, Gitaka J, Nolder D, Beshir KB, Dombrowski JG, Di Santi SM, Bousema T, Sutherland CJ, Campino S, Clark TG. Rapid profiling of Plasmodium parasites from genome sequences to assist malaria control. Genome Med 2023; 15:96. [PMID: 37950308 PMCID: PMC10636944 DOI: 10.1186/s13073-023-01247-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 10/13/2023] [Indexed: 11/12/2023] Open
Abstract
BACKGROUND Malaria continues to be a major threat to global public health. Whole genome sequencing (WGS) of the underlying Plasmodium parasites has provided insights into the genomic epidemiology of malaria. Genome sequencing is rapidly gaining traction as a diagnostic and surveillance tool for clinical settings, where the profiling of co-infections, identification of imported malaria parasites, and detection of drug resistance are crucial for infection control and disease elimination. To support this informatically, we have developed the Malaria-Profiler tool, which rapidly (within minutes) predicts Plasmodium species, geographical source, and resistance to antimalarial drugs directly from WGS data. RESULTS The online and command line versions of Malaria-Profiler detect ~ 250 markers from genome sequences covering Plasmodium speciation, likely geographical source, and resistance to chloroquine, sulfadoxine-pyrimethamine (SP), and other anti-malarial drugs for P. falciparum, but also providing mutations for orthologous resistance genes in other species. The predictive performance of the mutation library was assessed using 9321 clinical isolates with WGS and geographical data, with most being single-species infections (P. falciparum 7152/7462, P. vivax 1502/1661, P. knowlesi 143/151, P. malariae 18/18, P. ovale ssp. 5/5), but co-infections were identified (456/9321; 4.8%). The accuracy of the predicted geographical profiles was high to both continental (96.1%) and regional levels (94.6%). For P. falciparum, markers were identified for resistance to chloroquine (49.2%; regional range: 24.5% to 100%), sulfadoxine (83.3%; 35.4- 90.5%), pyrimethamine (85.4%; 80.0-100%) and combined SP (77.4%). Markers associated with the partial resistance of artemisinin were found in WGS from isolates sourced from Southeast Asia (30.6%). CONCLUSIONS Malaria-Profiler is a user-friendly tool that can rapidly and accurately predict the geographical regional source and anti-malarial drug resistance profiles across large numbers of samples with WGS data. The software is flexible with modifiable bioinformatic pipelines. For example, it is possible to select the sequencing platform, display specific variants, and customise the format of outputs. With the increasing application of next-generation sequencing platforms on Plasmodium DNA, Malaria-Profiler has the potential to be integrated into point-of-care and surveillance settings, thereby assisting malaria control. Malaria-Profiler is available online (bioinformatics.lshtm.ac.uk/malaria-profiler) and as standalone software ( https://github.com/jodyphelan/malaria-profiler ).
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Affiliation(s)
- Jody E Phelan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, WC1E 7HT, UK.
| | - Anna Turkiewicz
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, WC1E 7HT, UK
| | - Emilia Manko
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, WC1E 7HT, UK
| | - Joseph Thorpe
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, WC1E 7HT, UK
| | - Leen N Vanheer
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, WC1E 7HT, UK
| | - Marga van de Vegte-Bolmer
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, University of Nijmegen, Nijmegen, The Netherlands
| | - Nguyen Thi Hong Ngoc
- Molecular Biology Department, Parasitology and Entomology, Vietnam National Institute of Malariology, Hanoi, Vietnam
| | - Nguyen Thi Huong Binh
- Molecular Biology Department, Parasitology and Entomology, Vietnam National Institute of Malariology, Hanoi, Vietnam
| | - Nguyen Quang Thieu
- Molecular Biology Department, Parasitology and Entomology, Vietnam National Institute of Malariology, Hanoi, Vietnam
| | - Jesse Gitaka
- Directorate of Research and Innovation, Mount Kenya University, Gen. Kago Rd, Thika, Kenya
| | - Debbie Nolder
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, WC1E 7HT, UK
- UK Health Security Agency Malaria Reference Laboratory, LSHTM, London, WC1E 7HT, UK
| | - Khalid B Beshir
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, WC1E 7HT, UK
| | - Jamille G Dombrowski
- Department of Parasitology, Institute of Biomedical Sciences, Univ. of São Paulo, São Paulo, Brazil
| | - Silvia Maria Di Santi
- School of Medicine, Instituto de Medicina Tropical, University of São Paulo, São Paulo, Brazil
| | - Teun Bousema
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, University of Nijmegen, Nijmegen, The Netherlands
| | - Colin J Sutherland
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, WC1E 7HT, UK
- UK Health Security Agency Malaria Reference Laboratory, LSHTM, London, WC1E 7HT, UK
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, WC1E 7HT, UK.
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, WC1E 7HT, UK.
- Faculty of Epidemiology and Population Health, LSHTM, London, WC1E 7HT, UK.
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Akoniyon OP, Adewumi TS, Maharaj L, Oyegoke OO, Roux A, Adeleke MA, Maharaj R, Okpeku M. Whole Genome Sequencing Contributions and Challenges in Disease Reduction Focused on Malaria. BIOLOGY 2022; 11:587. [PMID: 35453786 PMCID: PMC9027812 DOI: 10.3390/biology11040587] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 12/11/2022]
Abstract
Malaria elimination remains an important goal that requires the adoption of sophisticated science and management strategies in the era of the COVID-19 pandemic. The advent of next generation sequencing (NGS) is making whole genome sequencing (WGS) a standard today in the field of life sciences, as PCR genotyping and targeted sequencing provide insufficient information compared to the whole genome. Thus, adapting WGS approaches to malaria parasites is pertinent to studying the epidemiology of the disease, as different regions are at different phases in their malaria elimination agenda. Therefore, this review highlights the applications of WGS in disease management, challenges of WGS in controlling malaria parasites, and in furtherance, provides the roles of WGS in pursuit of malaria reduction and elimination. WGS has invaluable impacts in malaria research and has helped countries to reach elimination phase rapidly by providing required information needed to thwart transmission, pathology, and drug resistance. However, to eliminate malaria in sub-Saharan Africa (SSA), with high malaria transmission, we recommend that WGS machines should be readily available and affordable in the region.
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Affiliation(s)
- Olusegun Philip Akoniyon
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Taiye Samson Adewumi
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Leah Maharaj
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Olukunle Olugbenle Oyegoke
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Alexandra Roux
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Matthew A. Adeleke
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Rajendra Maharaj
- Office of Malaria Research, South African Medical Research Council, Cape Town 7505, South Africa;
| | - Moses Okpeku
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
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Deelder W, Benavente ED, Phelan J, Manko E, Campino S, Palla L, Clark TG. Using deep learning to identify recent positive selection in malaria parasite sequence data. Malar J 2021; 20:270. [PMID: 34126997 PMCID: PMC8201710 DOI: 10.1186/s12936-021-03788-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/29/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Malaria, caused by Plasmodium parasites, is a major global public health problem. To assist an understanding of malaria pathogenesis, including drug resistance, there is a need for the timely detection of underlying genetic mutations and their spread. With the increasing use of whole-genome sequencing (WGS) of Plasmodium DNA, the potential of deep learning models to detect loci under recent positive selection, historically signals of drug resistance, was evaluated. METHODS A deep learning-based approach (called "DeepSweep") was developed, which can be trained on haplotypic images from genetic regions with known sweeps, to identify loci under positive selection. DeepSweep software is available from https://github.com/WDee/Deepsweep . RESULTS Using simulated genomic data, DeepSweep could detect recent sweeps with high predictive accuracy (areas under ROC curve > 0.95). DeepSweep was applied to Plasmodium falciparum (n = 1125; genome size 23 Mbp) and Plasmodium vivax (n = 368; genome size 29 Mbp) WGS data, and the genes identified overlapped with two established extended haplotype homozygosity methods (within-population iHS, across-population Rsb) (~ 60-75% overlap of hits at P < 0.0001). DeepSweep hits included regions proximal to known drug resistance loci for both P. falciparum (e.g. pfcrt, pfdhps and pfmdr1) and P. vivax (e.g. pvmrp1). CONCLUSION The deep learning approach can detect positive selection signatures in malaria parasite WGS data. Further, as the approach is generalizable, it may be trained to detect other types of selection. With the ability to rapidly generate WGS data at low cost, machine learning approaches (e.g. DeepSweep) have the potential to assist parasite genome-based surveillance and inform malaria control decision-making.
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Affiliation(s)
- Wouter Deelder
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
- Dalberg Advisors, 7 Rue de Chantepoulet, CH-1201, Geneva, Switzerland
| | | | - Jody Phelan
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Emilia Manko
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Susana Campino
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Luigi Palla
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
- Department of Public Health and Infectious Diseases, University of Rome La Sapienza, Rome, Italy
| | - Taane G Clark
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
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Liu S, Huckaby AC, Brown AC, Moore CC, Burbulis I, McConnell MJ, Güler JL. Single-cell sequencing of the small and AT-skewed genome of malaria parasites. Genome Med 2021; 13:75. [PMID: 33947449 PMCID: PMC8094492 DOI: 10.1186/s13073-021-00889-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 04/17/2021] [Indexed: 12/23/2022] Open
Abstract
Single-cell genomics is a rapidly advancing field; however, most techniques are designed for mammalian cells. We present a single-cell sequencing pipeline for an intracellular parasite, Plasmodium falciparum, with a small genome of extreme base content. Through optimization of a quasi-linear amplification method, we target the parasite genome over contaminants and generate coverage levels allowing detection of minor genetic variants. This work, as well as efforts that build on these findings, will enable detection of parasite heterogeneity contributing to P. falciparum adaptation. Furthermore, this study provides a framework for optimizing single-cell amplification and variant analysis in challenging genomes.
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Affiliation(s)
- Shiwei Liu
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Adam C Huckaby
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Audrey C Brown
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Christopher C Moore
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA
| | - Ian Burbulis
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA
- Escuela de Medicina, Universidad San Sebastian, Puerto Montt, Chile
| | - Michael J McConnell
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Current address: Lieber Institute for Brain Development, Baltimore, MD, USA
| | - Jennifer L Güler
- Department of Biology, University of Virginia, Charlottesville, VA, USA.
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA.
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5
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Da Veiga Leal S, Ward D, Campino S, Benavente ED, Ibrahim A, Claret T, Isaías V, Monteiro D, Clark TG, Gonçalves L, Valdez T, da Luz Lima Mendonça M, Silveira H, Nogueira F. Drug resistance profile and clonality of Plasmodium falciparum parasites in Cape Verde: the 2017 malaria outbreak. Malar J 2021; 20:172. [PMID: 33789667 PMCID: PMC8011132 DOI: 10.1186/s12936-021-03708-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/17/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cape Verde is an archipelago located off the West African coast and is in a pre-elimination phase of malaria control. Since 2010, fewer than 20 Plasmodium falciparum malaria cases have been reported annually, except in 2017, when an outbreak in Praia before the rainy season led to 423 autochthonous cases. It is important to understand the genetic diversity of circulating P. falciparum to inform on drug resistance, potential transmission networks and sources of infection, including parasite importation. METHODS Enrolled subjects involved malaria patients admitted to Dr Agostinho Neto Hospital at Praia city, Santiago island, Cape Verde, between July and October 2017. Neighbours and family members of enrolled cases were assessed for the presence of anti-P. falciparum antibodies. Sanger sequencing and real-time PCR was used to identify SNPs in genes associated with drug resistance (e.g., pfdhfr, pfdhps, pfmdr1, pfk13, pfcrt), and whole genome sequencing data were generated to investigate the population structure of P. falciparum parasites. RESULTS The study analysed 190 parasite samples, 187 indigenous and 3 from imported infections. Malaria cases were distributed throughout Praia city. There were no cases of severe malaria and all patients had an adequate clinical and parasitological response after treatment. Anti-P. falciparum antibodies were not detected in the 137 neighbours and family members tested. No mutations were detected in pfdhps. The triple mutation S108N/N51I/C59R in pfdhfr and the chloroquine-resistant CVIET haplotype in the pfcrt gene were detected in almost all samples. Variations in pfk13 were identified in only one sample (R645T, E668K). The haplotype NFD for pfmdr1 was detected in the majority of samples (89.7%). CONCLUSIONS Polymorphisms in pfk13 associated with artemisinin-based combination therapy (ACT) tolerance in Southeast Asia were not detected, but the majority of the tested samples carried the pfmdr1 haplotype NFD and anti-malarial-associated mutations in the the pfcrt and pfdhfr genes. The first whole genome sequencing (WGS) was performed for Cape Verdean parasites that showed that the samples cluster together, have a very high level of similarity and are close to other parasites populations from West Africa.
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Affiliation(s)
- Silvania Da Veiga Leal
- Laboratório de Entomologia Médica, Largo Do Desastre da Assistência, Instituto Nacional de Saúde Pública, Chã de Areia, Praia 719, Cape Verde.
| | - Daniel Ward
- Department of Infection and Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Susana Campino
- Department of Infection and Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Ernest Diez Benavente
- Department of Infection and Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Amy Ibrahim
- Department of Infection and Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Tânia Claret
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Varela Isaías
- Laboratório de Entomologia Médica, Largo Do Desastre da Assistência, Instituto Nacional de Saúde Pública, Chã de Areia, Praia 719, Cape Verde
| | - Davidson Monteiro
- Laboratório de Entomologia Médica, Largo Do Desastre da Assistência, Instituto Nacional de Saúde Pública, Chã de Areia, Praia 719, Cape Verde
| | - Taane G Clark
- Department of Infection and Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene E Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Rua da Junqueira 100, 1349-008, Lisbon, Portugal
| | - Luzia Gonçalves
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene E Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Rua da Junqueira 100, 1349-008, Lisbon, Portugal
- Centro de Estatística E Aplicações da Universidade de Lisboa (CEAUL), Campo Grande, Bloco C6, Piso 4, 1749-016, Lisbon, Portugal
| | - Tomas Valdez
- Ministério da Saúde E da Segurança, Palácio Do Governo, nº47, Praia, Cape Verde
| | - Maria da Luz Lima Mendonça
- Laboratório de Entomologia Médica, Largo Do Desastre da Assistência, Instituto Nacional de Saúde Pública, Chã de Areia, Praia 719, Cape Verde
| | - Henrique Silveira
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene E Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Rua da Junqueira 100, 1349-008, Lisbon, Portugal
| | - Fatima Nogueira
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene E Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Rua da Junqueira 100, 1349-008, Lisbon, Portugal
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Lamb HJ, Hayes BJ, Nguyen LT, Ross EM. The Future of Livestock Management: A Review of Real-Time Portable Sequencing Applied to Livestock. Genes (Basel) 2020; 11:E1478. [PMID: 33317066 PMCID: PMC7763041 DOI: 10.3390/genes11121478] [Citation(s) in RCA: 8] [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] [Received: 08/28/2020] [Revised: 11/10/2020] [Accepted: 12/01/2020] [Indexed: 12/12/2022] Open
Abstract
Oxford Nanopore Technologies' MinION has proven to be a valuable tool within human and microbial genetics. Its capacity to produce long reads in real time has opened up unique applications for portable sequencing. Examples include tracking the recent African swine fever outbreak in China and providing a diagnostic tool for disease in the cassava plant in Eastern Africa. Here we review the current applications of Oxford Nanopore sequencing in livestock, then focus on proposed applications in livestock agriculture for rapid diagnostics, base modification detection, reference genome assembly and genomic prediction. In particular, we propose a future application: 'crush-side genotyping' for real-time on-farm genotyping for extensive industries such as northern Australian beef production. An initial in silico experiment to assess the feasibility of crush-side genotyping demonstrated promising results. SNPs were called from simulated Nanopore data, that included the relatively high base call error rate that is characteristic of the data, and calling parameters were varied to understand the feasibility of SNP calling at low coverages in a heterozygous population. With optimised genotype calling parameters, over 85% of the 10,000 simulated SNPs were able to be correctly called with coverages as low as 6×. These results provide preliminary evidence that Oxford Nanopore sequencing has potential to be used for real-time SNP genotyping in extensive livestock operations.
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Affiliation(s)
- Harrison J. Lamb
- Centre for Animal Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD 4067, Australia; (B.J.H.); (L.T.N.); (E.M.R.)
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7
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Turkiewicz A, Manko E, Sutherland CJ, Diez Benavente E, Campino S, Clark TG. Genetic diversity of the Plasmodium falciparum GTP-cyclohydrolase 1, dihydrofolate reductase and dihydropteroate synthetase genes reveals new insights into sulfadoxine-pyrimethamine antimalarial drug resistance. PLoS Genet 2020; 16:e1009268. [PMID: 33382691 PMCID: PMC7774857 DOI: 10.1371/journal.pgen.1009268] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 11/10/2020] [Indexed: 12/13/2022] Open
Abstract
Plasmodium falciparum parasites resistant to antimalarial treatments have hindered malaria disease control. Sulfadoxine-pyrimethamine (SP) was used globally as a first-line treatment for malaria after wide-spread resistance to chloroquine emerged and, although replaced by artemisinin combinations, is currently used as intermittent preventive treatment of malaria in pregnancy and in young children as part of seasonal malaria chemoprophylaxis in sub-Saharan Africa. The emergence of SP-resistant parasites has been predominantly driven by cumulative build-up of mutations in the dihydrofolate reductase (pfdhfr) and dihydropteroate synthetase (pfdhps) genes, but additional amplifications in the folate pathway rate-limiting pfgch1 gene and promoter, have recently been described. However, the genetic make-up and prevalence of those amplifications is not fully understood. We analyse the whole genome sequence data of 4,134 P. falciparum isolates across 29 malaria endemic countries, and reveal that the pfgch1 gene and promoter amplifications have at least ten different forms, occurring collectively in 23% and 34% in Southeast Asian and African isolates, respectively. Amplifications are more likely to be present in isolates with a greater accumulation of pfdhfr and pfdhps substitutions (median of 1 additional mutations; P<0.00001), and there was evidence that the frequency of pfgch1 variants may be increasing in some African populations, presumably under the pressure of SP for chemoprophylaxis and anti-folate containing antibiotics used for the treatment of bacterial infections. The selection of P. falciparum with pfgch1 amplifications may enhance the fitness of parasites with pfdhfr and pfdhps substitutions, potentially threatening the efficacy of this regimen for prevention of malaria in vulnerable groups. Our work describes new pfgch1 amplifications that can be used to inform the surveillance of SP drug resistance, its prophylactic use, and future experimental work to understand functional mechanisms.
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Affiliation(s)
- Anna Turkiewicz
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Emilia Manko
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Colin J. Sutherland
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ernest Diez Benavente
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Susana Campino
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Taane G. Clark
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
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