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Jones BP, Kozel K, Alonte AJI, Llanes KKR, Juhász A, Chaudhry U, Roose S, Geldhof P, Belizario VY, Nejsum P, Stothard JR, LaCourse EJ, van Vliet AHM, Paller VGV, Betson M. Worldwide absence of canonical benzimidazole resistance-associated mutations within β-tubulin genes from Ascaris. Parasit Vectors 2024; 17:225. [PMID: 38755679 PMCID: PMC11098727 DOI: 10.1186/s13071-024-06306-5] [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: 03/08/2024] [Accepted: 04/24/2024] [Indexed: 05/18/2024] Open
Abstract
BACKGROUND The giant roundworm Ascaris is an intestinal nematode, causing ascariasis by infecting humans and pigs worldwide. Recent estimates suggest that Ascaris infects over half a billion people, with chronic infections leading to reduced growth and cognitive ability. Ascariasis affects innumerable pigs worldwide and is known to reduce production yields via decreased growth and condemnation of livers. The predominant anthelminthic drugs used to treat ascariasis are the benzimidazoles. Benzimidazoles interact with β-tubulins and block their function, and several benzimidazole resistance-associated mutations have been described in the β-tubulins of ruminant nematodes. Recent research on ascarids has shown that these canonical benzimidazole resistance-associated mutations are likely not present in the β-tubulins of Ascaris, Ascaridia or Parascaris, even in phenotypically resistant populations. METHODS To further determine the putative absence of key β-tubulin polymorphisms, we screened two β-tubulin isotypes of Ascaris, highly expressed in adult worms. Using adult and egg samples of Ascaris obtained from pigs and humans worldwide, we performed deep amplicon sequencing to look for canonical resistance-associated mutations in Ascaris β-tubulins. Subsequently, we examined these data in closer detail to study the population dynamics of Ascaris and genetic diversity within the two isotypes and tested whether genotypes appeared to partition across human and pig hosts. RESULTS In the 187 isolates, 69 genotypes were found, made up of eight haplotypes of β-tubulin isotype A and 20 haplotypes of isotype B. Single nucleotide polymorphisms were seen at 14 and 37 positions for β-tubulin isotype A and isotype B, respectively. No evidence of any canonical benzimidazole resistance-associated mutations was found in either human- or pig-derived Ascaris isolates. There was, however, a difference in the genetic diversity of each isotype and distribution of β-tubulin genotypes between human- and pig-derived Ascaris. Statistical tests of population differentiation show significant differences (p < 0.001) between pig- and human-derived worms; however, more diversity was seen between worms from different populations than worms from different hosts. CONCLUSIONS Our work suggests an absence of canonical β-tubulin mutations within Ascaris, but alternative modes of anthelminthic resistance may emerge necessitating continued genetic scrutiny alongside monitoring of drug efficacy.
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Affiliation(s)
- Ben P Jones
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, GU2 7AL, UK
| | - Kezia Kozel
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, GU2 7AL, UK
| | - Allen Jethro I Alonte
- Institute of Biological Sciences, University of the Philippines Los Baños, Laguna, Philippines
| | - Kennesa Klariz R Llanes
- Institute of Biological Sciences, University of the Philippines Los Baños, Laguna, Philippines
| | - Alexandra Juhász
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
- Institute of Medical Microbiology, Semmelweis University, Budapest, Hungary
| | - Umer Chaudhry
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, GU2 7AL, UK
- School of Veterinary Medicine, St. George's University, True Blue, West Indies, Grenada
| | - Sara Roose
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Peter Geldhof
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Vicente Y Belizario
- Department of Parasitology, College of Public Health, University of the Philippines Manila, Manila, Philippines
| | - Peter Nejsum
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - J Russell Stothard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - E James LaCourse
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Arnoud H M van Vliet
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, GU2 7AL, UK
| | - Vachel Gay V Paller
- Institute of Biological Sciences, University of the Philippines Los Baños, Laguna, Philippines
| | - Martha Betson
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, GU2 7AL, UK.
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2
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Wolstenholme AJ, Andersen EC, Choudhary S, Ebner F, Hartmann S, Holden-Dye L, Kashyap SS, Krücken J, Martin RJ, Midha A, Nejsum P, Neveu C, Robertson AP, von Samson-Himmelstjerna G, Walker R, Wang J, Whitehead BJ, Williams PDE. Getting around the roundworms: Identifying knowledge gaps and research priorities for the ascarids. ADVANCES IN PARASITOLOGY 2024; 123:51-123. [PMID: 38448148 PMCID: PMC11143470 DOI: 10.1016/bs.apar.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
The ascarids are a large group of parasitic nematodes that infect a wide range of animal species. In humans, they cause neglected diseases of poverty; many animal parasites also cause zoonotic infections in people. Control measures include hygiene and anthelmintic treatments, but they are not always appropriate or effective and this creates a continuing need to search for better ways to reduce the human, welfare and economic costs of these infections. To this end, Le Studium Institute of Advanced Studies organized a two-day conference to identify major gaps in our understanding of ascarid parasites with a view to setting research priorities that would allow for improved control. The participants identified several key areas for future focus, comprising of advances in genomic analysis and the use of model organisms, especially Caenorhabditis elegans, a more thorough appreciation of the complexity of host-parasite (and parasite-parasite) communications, a search for novel anthelmintic drugs and the development of effective vaccines. The participants agreed to try and maintain informal links in the future that could form the basis for collaborative projects, and to co-operate to organize future meetings and workshops to promote ascarid research.
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Affiliation(s)
- Adrian J Wolstenholme
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Université de Tours, ISP, Nouzilly, France.
| | - Erik C Andersen
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States
| | - Shivani Choudhary
- Department of Biomedical Sciences, Iowa State University, Ames, IA, United States
| | - Friederike Ebner
- Department of Molecular Life Sciences, School of Life Sciences, Technische Universität München, Freising, Germany
| | - Susanne Hartmann
- Institute for Immunology, Freie Universität Berlin, Berlin, Germany
| | - Lindy Holden-Dye
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Sudhanva S Kashyap
- Department of Biomedical Sciences, Iowa State University, Ames, IA, United States
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Richard J Martin
- Department of Biomedical Sciences, Iowa State University, Ames, IA, United States
| | - Ankur Midha
- Institute for Immunology, Freie Universität Berlin, Berlin, Germany
| | - Peter Nejsum
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Cedric Neveu
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Université de Tours, ISP, Nouzilly, France
| | - Alan P Robertson
- Department of Biomedical Sciences, Iowa State University, Ames, IA, United States
| | | | - Robert Walker
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Jianbin Wang
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, United States
| | | | - Paul D E Williams
- Department of Biomedical Sciences, Iowa State University, Ames, IA, United States
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3
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Ng'etich AI, Amoah ID, Bux F, Kumari S. Anthelmintic resistance in soil-transmitted helminths: One-Health considerations. Parasitol Res 2023; 123:62. [PMID: 38114766 PMCID: PMC10730643 DOI: 10.1007/s00436-023-08088-8] [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: 07/03/2023] [Accepted: 12/05/2023] [Indexed: 12/21/2023]
Abstract
The One-Health approach recognizes the intricate connection between human, animal, and environmental health, and that cooperative effort from various professionals provides comprehensive awareness and potential solutions for issues relating to the health of people, animals, and the environment. This approach has increasingly gained appeal as the standard strategy for tackling emerging infectious diseases, most of which are zoonoses. Treatment with anthelmintics (AHs) without a doubt minimizes the severe consequences of soil-transmitted helminths (STHs); however, evidence of anthelmintic resistance (AR) development to different helminths of practically every animal species and the distinct groups of AHs is overwhelming globally. In this regard, the correlation between the application of anthelmintic drugs in both human and animal populations and the consequent development of anthelmintic resistance in STHs within the context of a One-Health framework is explored. This review provides an overview of the major human and animal STHs, treatment of the STHs, AR development and drug-related factors contributing towards AR, One-Health and STHs, and an outline of some One-Health strategies that may be used in combating AR.
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Affiliation(s)
- Annette Imali Ng'etich
- Institute for Water and Wastewater Technology, Durban University of Technology (DUT), Durban, South Africa
| | - Isaac Dennis Amoah
- Institute for Water and Wastewater Technology, Durban University of Technology (DUT), Durban, South Africa
- Department of Environmental Science, University of Arizona, Tucson, AZ, USA
| | - Faizal Bux
- Institute for Water and Wastewater Technology, Durban University of Technology (DUT), Durban, South Africa
| | - Sheena Kumari
- Institute for Water and Wastewater Technology, Durban University of Technology (DUT), Durban, South Africa.
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4
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Collins JB, Andersen EC. The turkey ascarid, Ascaridia dissimilis, as a model genetic system. Int J Parasitol 2023; 53:405-409. [PMID: 36549442 PMCID: PMC10258144 DOI: 10.1016/j.ijpara.2022.10.005] [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: 07/15/2022] [Revised: 10/02/2022] [Accepted: 10/25/2022] [Indexed: 12/23/2022]
Abstract
Parasitic nematodes cause significant effects on humans each year, with the most prevalent being Ascaris lumbricoides. Benzimidazoles (BZ) are the most widely used anthelmintic drug in humans, and although the biology of resistance to this drug class is understood in some species, resistance is poorly characterized in ascarids. Models such as Caenorhabditis elegans were essential in developing our current understanding of BZ resistance, but more closely related model nematodes are needed to understand resistance in ascarids. Here, we propose a new ascarid model species that infects turkeys, Ascaridia dissimilis, to develop a better understanding of BZ resistance.
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Affiliation(s)
- J B Collins
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Erik C Andersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
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Thorn CS, Maness RW, Hulke JM, Delmore KE, Criscione CD. Population genomics of helminth parasites. J Helminthol 2023; 97:e29. [PMID: 36927601 DOI: 10.1017/s0022149x23000123] [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] [Indexed: 03/18/2023]
Abstract
Next generation sequencing technologies have facilitated a shift from a few targeted loci in population genetic studies to whole genome approaches. Here, we review the types of questions and inferences regarding the population biology and evolution of parasitic helminths being addressed within the field of population genomics. Topics include parabiome, hybridization, population structure, loci under selection and linkage mapping. We highlight various advances, and note the current trends in the field, particularly a focus on human-related parasites despite the inherent biodiversity of helminth species. We conclude by advocating for a broader application of population genomics to reflect the taxonomic and life history breadth displayed by helminth parasites. As such, our basic knowledge about helminth population biology and evolution would be enhanced while the diversity of helminths in itself would facilitate population genomic comparative studies to address broader ecological and evolutionary concepts.
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Affiliation(s)
- C S Thorn
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX, 77843, USA
| | - R W Maness
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX, 77843, USA
| | - J M Hulke
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX, 77843, USA
| | - K E Delmore
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX, 77843, USA
| | - C D Criscione
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX, 77843, USA
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6
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Pilotte N, Manuel M, Walson JL, Ajjampur SSR. Community-wide mass drug administration for soil-transmitted helminths – risk of drug resistance and mitigation strategies. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.897155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mass drug administration programs for the control of soil-transmitted helminths (STH) in humans most commonly utilize a single class of drugs; the benzimidazoles. Most such programs focus on the treatment of pre-school and school aged children attending schools, although there is increasing interest in the potential utility of community-wide MDA to reduce infection intensity within communities and possibly to interrupt STH transmission. In animals, mass treatment with benzimidazoles leads to the rapid selection of parasites containing resistance-encoding single nucleotide polymorphisms (SNP) and the potential emergence of resistance in parasite species that infect humans is of major potential public health concern. As programs scale up delivery of anthelmintics and consider expanding treated populations, monitoring of drug efficacy and the potential emergence of anthelmintic resistance with sensitive diagnostic tools is critical to ensure the continued success of STH control programs. In particular, as programs consider the adoption of community-wide deworming, there is concern that such a strategy may increase the risk of drug resistance by limiting the number of untreated individuals which serve as a refugia of unexposed worm populations. We review the literature for evidence of drug resistance in human STH infections and explore risks and mitigation strategies for emergence of drug resistance in the context of community-wide deworming.
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7
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Rinaldi L, Krücken J, Martinez-Valladares M, Pepe P, Maurelli MP, de Queiroz C, Castilla Gómez de Agüero V, Wang T, Cringoli G, Charlier J, Gilleard JS, von Samson-Himmelstjerna G. Advances in diagnosis of gastrointestinal nematodes in livestock and companion animals. ADVANCES IN PARASITOLOGY 2022; 118:85-176. [PMID: 36088084 DOI: 10.1016/bs.apar.2022.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Diagnosis of gastrointestinal nematodes in livestock and companion animals has been neglected for years and there has been an historical underinvestment in the development and improvement of diagnostic tools, undermining the undoubted utility of surveillance and control programmes. However, a new impetus by the scientific community and the quickening pace of technological innovations, are promoting a renaissance of interest in developing diagnostic capacity for nematode infections in veterinary parasitology. A cross-cutting priority for diagnostic tools is the development of pen-side tests and associated decision support tools that rapidly inform on the levels of infection and morbidity. This includes development of scalable, parasite detection using artificial intelligence for automated counting of parasitic elements and research towards establishing biomarkers using innovative molecular and proteomic methods. The aim of this review is to assess the state-of-the-art in the diagnosis of helminth infections in livestock and companion animals and presents the current advances of diagnostic methods for intestinal parasites harnessing (i) automated methods for copromicroscopy based on artificial intelligence, (ii) immunodiagnosis, and (iii) molecular- and proteome-based approaches. Regardless of the method used, multiple factors need to be considered before diagnostics test results can be interpreted in terms of control decisions. Guidelines on how to apply diagnostics and how to interpret test results in different animal species are increasingly requested and some were recently made available in veterinary parasitology for the different domestic species.
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Affiliation(s)
- Laura Rinaldi
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Naples, Italy.
| | - J Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany
| | - M Martinez-Valladares
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de León, León, Spain
| | - P Pepe
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Naples, Italy
| | - M P Maurelli
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Naples, Italy
| | - C de Queiroz
- Faculty of Veterinary Medicine, 3331 Hospital Drive, Host-Parasite Interactions (HPI) Program University of Calgary, Calgary, Alberta, Canada; Faculty of Veterinary Medicine, St Georges University, Grenada
| | - V Castilla Gómez de Agüero
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de León, León, Spain
| | - T Wang
- Kreavet, Kruibeke, Belgium
| | - Giuseppe Cringoli
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Naples, Italy
| | | | - J S Gilleard
- Faculty of Veterinary Medicine, 3331 Hospital Drive, Host-Parasite Interactions (HPI) Program University of Calgary, Calgary, Alberta, Canada
| | - G von Samson-Himmelstjerna
- Institute for Parasitology and Tropical Veterinary Medicine, Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany
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8
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Jones BP, van Vliet AHM, LaCourse EJ, Betson M. Identification of key interactions of benzimidazole resistance-associated amino acid mutations in Ascaris β-tubulins by molecular docking simulations. Sci Rep 2022; 12:13725. [PMID: 35961997 PMCID: PMC9374697 DOI: 10.1038/s41598-022-16765-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 07/14/2022] [Indexed: 11/09/2022] Open
Abstract
Ascaris species are soil-transmitted helminths that infect humans and livestock mainly in low and middle-income countries. Benzimidazole (BZ) class drugs have predominated for many years in the treatment of Ascaris infections, but persistent use of BZs has already led to widespread resistance in other nematodes, and treatment failure is emerging for Ascaris. Benzimidazoles act by binding to β-tubulin proteins and destabilising microtubules. Three mutations in the β-tubulin protein family are associated with BZ resistance. Seven shared β-tubulin isotypes were identified in Ascaris lumbricoides and A. suum genomes. Benzimidazoles were predicted to bind to all β-tubulin isotypes using in silico docking, demonstrating that the selectivity of BZs to interact with one or two β-tubulin isotypes is likely the result of isotype expression levels affecting the frequency of interaction. Ascaris β-tubulin isotype A clusters with helminth β-tubulins previously shown to interact with BZ. Molecular dynamics simulations using β-tubulin isotype A highlighted the key role of amino acid E198 in BZ-β-tubulin interactions. Simulations indicated that mutations at amino acids E198A and F200Y alter binding of BZ, whereas there was no obvious effect of the F167Y mutation. In conclusion, the key interactions vital for BZ binding with β-tubulins have been identified and show how mutations can lead to resistance in nematodes.
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Affiliation(s)
- Ben P Jones
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, UK
| | - Arnoud H M van Vliet
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, UK
| | - E James LaCourse
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Martha Betson
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, UK.
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Jones BP, van Vliet AHM, LaCourse EJ, Betson M. In Silico Docking of Nematode β-Tubulins With Benzimidazoles Points to Gene Expression and Orthologue Variation as Factors in Anthelmintic Resistance. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.898814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The efficacy of benzimidazole anthelmintics can vary depending on the target parasite, with Ascaris nematodes being highly responsive, and whipworms being less responsive. Anthelmintic resistance has become widespread, particularly in strongyle nematodes such as Haemonchus contortus in ruminants, and resistance has recently been detected in hookworms of humans and dogs. Past work has shown that there are multiple β-tubulin isotypes in helminths, yet only a few of these contribute to benzimidazole interactions and resistance. The β-tubulin isotypes of ascarids and soil-transmitted helminths were identified by mining available genome data, and phylogenetic analysis showed that the ascarids share a similar repertoire of seven β-tubulin isotypes. Strongyles also have a consistent pattern of four β-tubulin isotypes. In contrast, the whipworms only have two isotypes, with one of these clustering more basally and distinct from any other group. Key β-tubulin isotypes selected based on previous studies were the focus of in silico molecular docking simulations to look at the interactions with benzimidazoles. These showed that all β-tubulins had similar interactions with benzimidazoles and maintained the key bond with residue E198 in all species, indicating similar mechanisms of action. However, the interaction was stronger and more consistent in the strongyles and whipworms than it was in the ascarids. Alteration of β-tubulin isotypes with the common resistance-associated mutations originally identified in H. contortus resulted in similar interaction modeling for all species. In conclusion, ascarids, strongyles, and whipworms all have their own unique repertoire of β-tubulins, which could explain why benzimidazole resistance and susceptibility varies between these groups of parasites. These data complement recent work that has highlighted the roles of essential residues in benzimidazole drug binding and shows that there is a separation between strongyle parasites that frequently develop resistance and ascarid parasites, which have been much less prone to developing resistance.
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Absence of Polymorphisms in Codons 167, 198 and 200 of All Seven β-tubulin Isotypes of Benzimidazole Susceptible and Resistant Parascaris spp. Specimens from Australia. Pathogens 2022; 11:pathogens11050490. [PMID: 35631011 PMCID: PMC9143322 DOI: 10.3390/pathogens11050490] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/14/2022] [Accepted: 04/19/2022] [Indexed: 11/24/2022] Open
Abstract
Benzimidazoles resistance is widespread in strongyle parasitic nematodes and associated with polym orphisms in the codons 167, 198 and 200 of isotype 1 β-tubulin (tbb-1). In ascarids, benzimidazole (BZ) resistance has rarely been reported and in none of these cases were any of these polymorphisms detected. Here, available genome and transcriptome data from WormBase ParaSite were used to compare the complete β-tubulin reservoirs of Parascaris univalens, Ascaris suum and Ascaris lumbricoides. Adult Parascaris spp. specimens collected in Australia from horses after BZ treatment (susceptible, n = 13) or surviving BZ treatment and collected after ivermectin treatment (resistant, n = 10) were genotyped regarding codons 167, 198 and 200 using Sanger sequencing. Phylogenetic analyses clearly showed that there are no one-to-one ascarid orthologs of strongyle tbb-1 genes. In the reference genomes, as well as phenotypically susceptible and resistant Parascaris spp. from Australia, six out of seven β-tubulin genes showed a BZ-susceptible genotype (F167, E198, F200). The only exception were the testis-specific β-tubulin D genes from all three ascarid species that encode tyrosine at codon 200. This was observed independently of the BZ-susceptibility phenotype of Parascaris spp. These data suggest that different mechanisms lead to BZ resistance in ascarid and strongyle nematodes.
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Papaiakovou M, Littlewood DTJ, Doyle SR, Gasser RB, Cantacessi C. Worms and bugs of the gut: the search for diagnostic signatures using barcoding, and metagenomics-metabolomics. Parasit Vectors 2022; 15:118. [PMID: 35365192 PMCID: PMC8973539 DOI: 10.1186/s13071-022-05225-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/25/2022] [Indexed: 02/07/2023] Open
Abstract
Gastrointestinal (GI) helminth infections cause significant morbidity in both humans and animals worldwide. Specific and sensitive diagnosis is central to the surveillance of such infections and to determine the effectiveness of treatment strategies used to control them. In this article, we: (i) assess the strengths and limitations of existing methods applied to the diagnosis of GI helminth infections of humans and livestock; (ii) examine high-throughput sequencing approaches, such as targeted molecular barcoding and shotgun sequencing, as tools to define the taxonomic composition of helminth infections; and (iii) discuss the current understanding of the interactions between helminths and microbiota in the host gut. Stool-based diagnostics are likely to serve as an important tool well into the future; improved diagnostics of helminths and their environment in the gut may assist the identification of biomarkers with the potential to define the health/disease status of individuals and populations, and to identify existing or emerging anthelmintic resistance.
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Affiliation(s)
- Marina Papaiakovou
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES UK
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD UK
| | | | | | - Robin B. Gasser
- Melbourne Veterinary School, The University of Melbourne, Parkville, VIC 3010 Australia
| | - Cinzia Cantacessi
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES UK
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