1
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Rawson AM, Dempster AW, Humphreys CM, Minton NP. Pathogenicity and virulence of Clostridium botulinum. Virulence 2023; 14:2205251. [PMID: 37157163 PMCID: PMC10171130 DOI: 10.1080/21505594.2023.2205251] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023] Open
Abstract
Clostridium botulinum, a polyphyletic Gram-positive taxon of bacteria, is classified purely by their ability to produce botulinum neurotoxin (BoNT). BoNT is the primary virulence factor and the causative agent of botulism. A potentially fatal disease, botulism is classically characterized by a symmetrical descending flaccid paralysis, which is left untreated can lead to respiratory failure and death. Botulism cases are classified into three main forms dependent on the nature of intoxication; foodborne, wound and infant. The BoNT, regarded as the most potent biological substance known, is a zinc metalloprotease that specifically cleaves SNARE proteins at neuromuscular junctions, preventing exocytosis of neurotransmitters, leading to muscle paralysis. The BoNT is now used to treat numerous medical conditions caused by overactive or spastic muscles and is extensively used in the cosmetic industry due to its high specificity and the exceedingly small doses needed to exert long-lasting pharmacological effects. Additionally, the ability to form endospores is critical to the pathogenicity of the bacteria. Disease transmission is often facilitated via the metabolically dormant spores that are highly resistant to environment stresses, allowing persistence in the environment in unfavourable conditions. Infant and wound botulism infections are initiated upon germination of the spores into neurotoxin producing vegetative cells, whereas foodborne botulism is attributed to ingestion of preformed BoNT. C. botulinum is a saprophytic bacterium, thought to have evolved its potent neurotoxin to establish a source of nutrients by killing its host.
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Affiliation(s)
- Alexander M Rawson
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, The Biodiscovery Institute, The University of Nottingham, Nottingham, UK
| | - Andrew W Dempster
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, The Biodiscovery Institute, The University of Nottingham, Nottingham, UK
| | - Christopher M Humphreys
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, The Biodiscovery Institute, The University of Nottingham, Nottingham, UK
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2
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Poortmans M, Vanoirbeek K, Dorner MB, Michiels CW. Selection and Development of Nontoxic Nonproteolytic Clostridium botulinum Surrogate Strains for Food Challenge Testing. Foods 2022; 11:1577. [PMID: 35681327 PMCID: PMC9180612 DOI: 10.3390/foods11111577] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/18/2022] [Accepted: 05/23/2022] [Indexed: 02/05/2023] Open
Abstract
Clostridium botulinum causes severe foodborne intoxications by producing a potent neurotoxin. Challenge studies with this pathogen are an important tool to ensure the safety of new processing techniques and newly designed or modified foods, but they are hazardous and complicated by the lack of an effective selective counting medium. Therefore, this study aimed to develop selectable nontoxic surrogate strains for group II, or nonproteolytic, C. botulinum, which are psychotropic and hence of particular concern in mildly treated, refrigerated foods. Thirty-one natural nontoxic nonproteolytic strains, 16 of which were isolated in this work, were characterized in detail, revealing that 28 strains were genomically and phenotypically indistinguishable from toxic strains. Five strains, representing the genomic and phenotypic diversity of group II C. botulinum, were selected and successfully equipped with an erythromycin (Em) resistance marker in a defective structural phage gene without altering phenotypic features. Finally, a selective medium containing Em, cycloserine (Cs), gentamicin (Gm), and lysozyme (Ly) was developed, which inhibited the background microbiota of commercial cooked ham, chicken filet, and salami, but supported spore germination and growth of the Em-resistant surrogate strains. The surrogates developed in this work are expected to facilitate food challenge studies with nonproteolytic C. botulinum for the food industry and can also provide a safe alternative for basic C. botulinum research.
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Affiliation(s)
- Marijke Poortmans
- Department of Microbial and Molecular Systems, KU Leuven, 3000 Leuven, Belgium; (M.P.); (K.V.)
| | - Kristof Vanoirbeek
- Department of Microbial and Molecular Systems, KU Leuven, 3000 Leuven, Belgium; (M.P.); (K.V.)
| | - Martin B. Dorner
- Robert Koch Institute, ZBS3-Biological Toxins, Seestr. 10, 13353 Berlin, Germany;
| | - Chris W. Michiels
- Department of Microbial and Molecular Systems, KU Leuven, 3000 Leuven, Belgium; (M.P.); (K.V.)
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3
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Abstract
Botulinum neurotoxins (BoNTs) are the most toxic substances known to humankind and are the causative agents of the neuroparalytic disease botulism. Despite the overall importance of BoNTs in public health and safety, as a bioterrorism concern, and in pharmaceutical development, little is known about the molecular mechanisms mediating BoNT stability and degradation in various environments. Previous studies using Clostridium botulinum strain ATCC 3502 revealed that high levels of arginine (20 g/liter) repressed BoNT production approximately 1,000-fold. In the present study, the mechanisms of toxin reduction in arginine-enriched cultures of C. botulinum strain Hall A-hyper, which we have previously genetically manipulated using ClosTron technology, were explored. Cultures were grown in toxin production medium (TPM) and TPM enriched with arginine. Cultures were analyzed for growth (optical density at 600 nm [OD600]), changes in pH, and BoNT formation and stability. Our data indicate that arginine enrichment of C. botulinum strain Hall A-hyper cultures results in a pH shift that induces pH-dependent posttranslational control mechanisms. We further show that independent of arginine, maintenance of an acidic culture pH during growth of C. botulinum strain Hall A-hyper plays a central role in toxin stability and that an extracellular metalloprotease produced by the culture results in BoNT degradation at pH levels between ⁓6.5 and 8.0. IMPORTANCE Botulinum neurotoxin (BoNT) is a public health and bioterrorism concern as well as an important and widely used pharmaceutical, yet the regulation of its synthesis by BoNT-producing clostridia is not well understood. This paper highlights the role of environmentally controlled posttranslational regulatory mechanisms influencing processing and stability of biologically active BoNTs produced by C. botulinum. The results of this work will help enhance public health and safety measures and our ability to evaluate safety risks of novel BoNTs and improve production and quality of BoNTs for pharmaceutical use.
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4
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Garrigues L, Do TD, Bideaux C, Guillouet SE, Meynial-Salles I. Insights into Clostridium tetani: From genome to bioreactors. Biotechnol Adv 2021; 54:107781. [PMID: 34029623 DOI: 10.1016/j.biotechadv.2021.107781] [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: 11/12/2020] [Revised: 03/17/2021] [Accepted: 05/19/2021] [Indexed: 11/15/2022]
Abstract
Tetanus vaccination is of major importance for public health in most countries in the world. The World Health Organization indicated that 15,000 tetanus cases were reported in 2018 (Organization, World Health, 2019). Currently, vaccine manufacturers use tetanus toxin produced by Clostridium tetani fermentation in complex media. The complex components, commonly derived from animal sources, introduce potential variability in cultures. To achieve replicable fermentation and to avoid toxic or allergic reactions from animal-source compounds, several studies have tried to switch from complex to chemically defined media without affecting toxin titers. The present review introduces the current knowledge on i) C. tetani strain diversity, whole-genome sequences and metabolic networks; ii) toxin regulation and synthesis; and iii) culture media, cultivation processes and growth requirements. We critically reviewed the reported data on metabolism in C. tetani and completed comparative genomic and proteomic analyses with other Clostridia species. We integrated genomic data based on whole-genome sequence annotation, supplemented with cofactor specificities determined by protein sequence identity, in a new map of C. tetani central metabolism. This is the first data review that integrates insights from omics experiments on C. tetani. The overview of C. tetani physiology described here could provide support for the design of new chemically defined media devoid of complex sources for toxin production.
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Affiliation(s)
- Lucile Garrigues
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Thuy Duong Do
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Carine Bideaux
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
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Orellana CA, Zaragoza NE, Licona-Cassani C, Palfreyman RW, Cowie N, Moonen G, Moutafis G, Power J, Nielsen LK, Marcellin E. Time-course transcriptomics reveals that amino acids catabolism plays a key role in toxinogenesis and morphology in Clostridium tetani. ACTA ACUST UNITED AC 2020; 47:1059-1073. [DOI: 10.1007/s10295-020-02330-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 11/02/2020] [Indexed: 10/23/2022]
Abstract
Abstract
Tetanus is a fatal disease caused by Clostridium tetani infections. To prevent infections, a toxoid vaccine, developed almost a century ago, is routinely used in humans and animals. The vaccine is listed in the World Health Organisation list of Essential Medicines and can be produced and administered very cheaply in the developing world for less than one US Dollar per dose. Recent developments in both analytical tools and frameworks for systems biology provide industry with an opportunity to gain a deeper understanding of the parameters that determine C. tetani virulence and physiological behaviour in bioreactors. Here, we compared a traditional fermentation process with a fermentation medium supplemented with five heavily consumed amino acids. The experiment demonstrated that amino acid catabolism plays a key role in the virulence of C. tetani. The addition of the five amino acids favoured growth, decreased toxin production and changed C. tetani morphology. Using time-course transcriptomics, we created a “fermentation map”, which shows that the tetanus toxin transcriptional regulator BotR, P21 and the tetanus toxin gene was downregulated. Moreover, this in-depth analysis revealed potential genes that might be involved in C. tetani virulence regulation. We observed differential expression of genes related to cell separation, surface/cell adhesion, pyrimidine biosynthesis and salvage, flagellar motility, and prophage genes. Overall, the fermentation map shows that, mediated by free amino acid concentrations, virulence in C. tetani is regulated at the transcriptional level and affects a plethora of metabolic functions.
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Affiliation(s)
- Camila A Orellana
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.7870.8 0000 0001 2157 0406 Department of Chemical and Bioprocess Engineering, School of Engineering Pontificia Universidad Católica de Chile Santiago Chile
| | - Nicolas E Zaragoza
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
| | - Cuauhtemoc Licona-Cassani
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.419886.a 0000 0001 2203 4701 Centro de Biotecnología FEMSA Tecnológico de Monterrey Nuevo León Mexico
| | - Robin W Palfreyman
- grid.1003.2 0000 0000 9320 7537 Metabolomics Australia The University of Queensland 4072 Brisbane QLD Australia
| | - Nicholas Cowie
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
| | - Glenn Moonen
- Zoetis. 45 Poplar Road 3052 Parkville VIC Australia
| | | | - John Power
- Zoetis. 45 Poplar Road 3052 Parkville VIC Australia
| | - Lars K Nielsen
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.1003.2 0000 0000 9320 7537 Metabolomics Australia The University of Queensland 4072 Brisbane QLD Australia
- grid.5170.3 0000 0001 2181 8870 The Novo Nordisk Foundation Centre for Biosustainability Technical University of Denmark Kgs. Lyngby Denmark
| | - Esteban Marcellin
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.1003.2 0000 0000 9320 7537 Metabolomics Australia The University of Queensland 4072 Brisbane QLD Australia
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6
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Tetanus Toxin Synthesis is Under the Control of A Complex Network of Regulatory Genes in Clostridium tetani. Toxins (Basel) 2020; 12:toxins12050328. [PMID: 32429286 PMCID: PMC7290440 DOI: 10.3390/toxins12050328] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/06/2020] [Accepted: 05/08/2020] [Indexed: 12/19/2022] Open
Abstract
Clostridium tetani produces a potent neurotoxin, the tetanus toxin (TeNT), which is responsible for an often-fatal neurological disease (tetanus) characterized by spastic paralysis. Prevention is efficiently acquired by vaccination with the TeNT toxoid, which is obtained by C.tetani fermentation and subsequent purification and chemical inactivation. C.tetani synthesizes TeNT in a regulated manner. Indeed, the TeNT gene (tent) is mainly expressed in the late exponential and early stationary growth phases. The gene tetR (tetanus regulatory gene), located immediately upstream of tent, encodes an alternative sigma factor which was previously identified as a positive regulator of tent. In addition, the genome of C.tetani encodes more than 127 putative regulators, including 30 two-component systems (TCSs). Here, we investigated the impact of 12 regulators on TeNT synthesis which were selected based on their homology with related regulatory elements involved in toxin production in other clostridial species. Among nine TCSs tested, three of them impact TeNT production, including two positive regulators that indirectly stimulate tent and tetR transcription. One negative regulator was identified that interacts with both tent and tetR promoters. Two other TCSs showed a moderate effect: one binds to the tent promoter and weakly increases the extracellular TeNT level, and another one has a weak inverse effect. In addition, CodY (control of dciA (decoyinine induced operon) Y) but not Spo0A (sporulation stage 0) or the DNA repair protein Mfd (mutation frequency decline) positively controls TeNT synthesis by interacting with the tent promoter. Moreover, we found that inorganic phosphate and carbonate are among the environmental factors that control TeNT production. Our data show that TeNT synthesis is under the control of a complex network of regulators that are largely distinct from those involved in the control of toxin production in Clostridium botulinum or Clostridium difficile.
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7
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Moreira C, Ferreira MRA, Finger PF, Magalhães CG, Cunha CEP, Rodrigues RR, Otaka DY, Galvão CC, Salvarani FM, Moreira ÂN, Conceição FR. Protective efficacy of recombinant bacterin vaccine against botulism in cattle. Vaccine 2020; 38:2519-2526. [PMID: 32037222 DOI: 10.1016/j.vaccine.2020.01.089] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 12/18/2019] [Accepted: 01/29/2020] [Indexed: 12/11/2022]
Abstract
Botulism is a paralytic disease caused by the intoxication of neurotoxins produced by Clostridium botulinum. Among the seven immunologically distinct serotypes of neurotoxins (BoNTs A - G), serotypes C and D, or a chimeric fusion termed C/D or D/C, are responsible for animal botulism. The most effective way to prevent botulism in cattle is through vaccination; however, the commercially available vaccines produced by detoxification of native neurotoxins are time-consuming and hazardous. To overcome these drawbacks, a non-toxic recombinant vaccine was developed as an alternative. In this study, the recombinant protein vaccine was produced using an Escherichia coli cell-based system. The formaldehyde-inactivated E. coli is able to induce 7.45 ± 1.77 and 6.6 ± 1.28 IU/mL neutralizing mean titers against BoNTs C and D in cattle, respectively, determined by mouse neutralization bioassay, and was deemed protective by the Brazilian legislation. Moreover, when the levels of anti-BoNT/C and D were compared with those achieved by the recombinant purified vaccines, no significant statistical difference was observed. Cattle vaccinated with the commercial vaccine developed 1.33 and 3.33 IU/mL neutralizing mean titers against BoNT serotypes C and D, respectively. To the best of our knowledge, this study is the first report on recombinant E. coli bacterin vaccine against botulism. The vaccine was safe and effective in generating protective antibodies and, thus, represents an industry-friendly alternative for the prevention of cattle botulism.
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Affiliation(s)
- Clóvis Moreira
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, CEP 96160-000, Brazil
| | - Marcos R A Ferreira
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, CEP 96160-000, Brazil
| | - Paula F Finger
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, CEP 96160-000, Brazil
| | - Carolina G Magalhães
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, CEP 96160-000, Brazil
| | - Carlos E P Cunha
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, CEP 96160-000, Brazil
| | - Rafael R Rodrigues
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, CEP 96160-000, Brazil
| | - Denis Y Otaka
- Instituto de Medicina Veterinária, Universidade Federal do Pará, Castanhal, Pará, CEP 68740-970, Brazil
| | - Cleideanny C Galvão
- Instituto de Medicina Veterinária, Universidade Federal do Pará, Castanhal, Pará, CEP 68740-970, Brazil
| | - Felipe M Salvarani
- Instituto de Medicina Veterinária, Universidade Federal do Pará, Castanhal, Pará, CEP 68740-970, Brazil
| | - Ângela N Moreira
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, CEP 96160-000, Brazil
| | - Fabricio R Conceição
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, CEP 96160-000, Brazil.
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8
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Zaragoza NE, Orellana CA, Moonen GA, Moutafis G, Marcellin E. Vaccine Production to Protect Animals Against Pathogenic Clostridia. Toxins (Basel) 2019; 11:E525. [PMID: 31514424 PMCID: PMC6783934 DOI: 10.3390/toxins11090525] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 08/26/2019] [Accepted: 08/28/2019] [Indexed: 12/19/2022] Open
Abstract
Clostridium is a broad genus of anaerobic, spore-forming, rod-shaped, Gram-positive bacteria that can be found in different environments all around the world. The genus includes human and animal pathogens that produce potent exotoxins that cause rapid and potentially fatal diseases responsible for countless human casualties and billion-dollar annual loss to the agricultural sector. Diseases include botulism, tetanus, enterotoxemia, gas gangrene, necrotic enteritis, pseudomembranous colitis, blackleg, and black disease, which are caused by pathogenic Clostridium. Due to their ability to sporulate, they cannot be eradicated from the environment. As such, immunization with toxoid or bacterin-toxoid vaccines is the only protective method against infection. Toxins recovered from Clostridium cultures are inactivated to form toxoids, which are then formulated into multivalent vaccines. This review discusses the toxins, diseases, and toxoid production processes of the most common pathogenic Clostridium species, including Clostridiumbotulinum, Clostridiumtetani, Clostridiumperfringens, Clostridiumchauvoei, Clostridiumsepticum, Clostridiumnovyi and Clostridiumhemolyticum.
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Affiliation(s)
- Nicolas E. Zaragoza
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; (N.E.Z.); (C.A.O.)
| | - Camila A. Orellana
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; (N.E.Z.); (C.A.O.)
| | - Glenn A. Moonen
- Zoetis, 45 Poplar Road, Parkville VIC 3052, Australia; (G.A.M.); (G.M.)
| | - George Moutafis
- Zoetis, 45 Poplar Road, Parkville VIC 3052, Australia; (G.A.M.); (G.M.)
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; (N.E.Z.); (C.A.O.)
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9
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Revitt-Mills SA, Vidor CJ, Watts TD, Lyras D, Rood JI, Adams V. Virulence Plasmids of the Pathogenic Clostridia. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0034-2018. [PMID: 31111816 PMCID: PMC11257192 DOI: 10.1128/microbiolspec.gpp3-0034-2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Indexed: 12/12/2022] Open
Abstract
The clostridia cause a spectrum of diseases in humans and animals ranging from life-threatening tetanus and botulism, uterine infections, histotoxic infections and enteric diseases, including antibiotic-associated diarrhea, and food poisoning. The symptoms of all these diseases are the result of potent protein toxins produced by these organisms. These toxins are diverse, ranging from a multitude of pore-forming toxins to phospholipases, metalloproteases, ADP-ribosyltransferases and large glycosyltransferases. The location of the toxin genes is the unifying theme of this review because with one or two exceptions they are all located on plasmids or on bacteriophage that replicate using a plasmid-like intermediate. Some of these plasmids are distantly related whilst others share little or no similarity. Many of these toxin plasmids have been shown to be conjugative. The mobile nature of these toxin genes gives a ready explanation of how clostridial toxin genes have been so widely disseminated both within the clostridial genera as well as in the wider bacterial community.
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Affiliation(s)
- Sarah A Revitt-Mills
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Callum J Vidor
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Thomas D Watts
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Dena Lyras
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Julian I Rood
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Vicki Adams
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
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10
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Abstract
Tetanus is a vaccine-preventable disease that still commonly occurs in many low-income and middle-income countries, although it is rare in high-income countries. The disease is caused by the toxin of the bacterium Clostridium tetani and is characterised by muscle spasms and autonomic nervous system dysfunction. Global vaccination initiatives have had considerable success but they continue to face many challenges. Treatment for tetanus aims to control spasms and reduce cardiovascular instability, and consists of wound debridement, antitoxin, antibiotics, and supportive care. Recent research has focused on intravenous magnesium sulphate and intrathecal antitoxin administration as methods of spasm control that can avoid the need for ventilatory support. Nevertheless, without access to mechanical ventilation, mortality from tetanus remains high. Even with such care, patients require several weeks of hospitalisation and are vulnerable to secondary problems, such as hospital-acquired infections.
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Affiliation(s)
- Lam Minh Yen
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - C Louise Thwaites
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam; Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK.
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11
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Selby K, Mascher G, Somervuo P, Lindström M, Korkeala H. Heat shock and prolonged heat stress attenuate neurotoxin and sporulation gene expression in group I Clostridium botulinum strain ATCC 3502. PLoS One 2017; 12:e0176944. [PMID: 28464023 PMCID: PMC5413062 DOI: 10.1371/journal.pone.0176944] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 04/19/2017] [Indexed: 12/11/2022] Open
Abstract
Foodborne pathogenic bacteria are exposed to a number of environmental stresses during food processing, storage, and preparation, and in the human body. In order to improve the safety of food, the understanding of molecular stress response mechanisms foodborne pathogens employ is essential. Many response mechanisms that are activated during heat shock may cross-protect bacteria against other environmental stresses. To better understand the molecular mechanisms Clostridium botulinum, the causative agent of botulism, utilizes during acute heat stress and during adaptation to stressfully high temperature, the C. botulinum Group I strain ATCC 3502 was grown in continuous culture at 39°C and exposed to heat shock at 45°C, followed by prolonged heat stress at 45°C to allow adaptation of the culture to the high temperature. Growth in continuous culture was performed to exclude secondary growth phase effects or other environmental impacts on bacterial gene transcription. Changes in global gene expression profiles were studied using DNA microarray hybridization. During acute heat stress, Class I and III heat shock genes as well as members of the SOS regulon were activated. The neurotoxin gene botA and genes encoding the neurotoxin-associated proteins were suppressed throughout the study. Prolonged heat stress led to suppression of the sporulation machinery whereas genes related to chemotaxis and motility were activated. Induced expression of a large proportion of prophage genes was detected, suggesting an important role of acquired genes in the stress resistance of C. botulinum. Finally, changes in the expression of a large number of genes related to carbohydrate and amino acid metabolism indicated remodeling of the cellular metabolism.
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Affiliation(s)
- Katja Selby
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Gerald Mascher
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Panu Somervuo
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Miia Lindström
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
- * E-mail:
| | - Hannu Korkeala
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
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12
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Licona-Cassani C, Steen JA, Zaragoza NE, Moonen G, Moutafis G, Hodson MP, Power J, Nielsen LK, Marcellin E. Tetanus toxin production is triggered by the transition from amino acid consumption to peptides. Anaerobe 2016; 41:113-124. [PMID: 27492724 DOI: 10.1016/j.anaerobe.2016.07.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 07/27/2016] [Accepted: 07/27/2016] [Indexed: 01/21/2023]
Abstract
Bacteria produce some of the most potent biomolecules known, of which many cause serious diseases such as tetanus. For prevention, billions of people and countless animals are immunised with the highly effective vaccine, industrially produced by large-scale fermentation. However, toxin production is often hampered by low yields and batch-to-batch variability. Improved productivity has been constrained by a lack of understanding of the molecular mechanisms controlling toxin production. Here we have developed a reproducible experimental framework for screening phenotypic determinants in Clostridium tetani under a process that mimics an industrial setting. We show that amino acid depletion induces production of the tetanus toxin. Using time-course transcriptomics and extracellular metabolomics to generate a 'fermentation atlas' that ascribe growth behaviour, nutrient consumption and gene expression to the fermentation phases, we found a subset of preferred amino acids. Exponential growth is characterised by the consumption of those amino acids followed by a slower exponential growth phase where peptides are consumed, and toxin is produced. The results aim at assisting in fermentation medium design towards the improvement of vaccine production yields and reproducibility. In conclusion, our work not only provides deep fermentation dynamics but represents the foundation for bioprocess design based on C. tetani physiological behaviour under industrial settings.
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Affiliation(s)
- Cuauhtemoc Licona-Cassani
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; National Laboratory of Genomics for Biodiversity (LANGEBIO), Cinvestav-IPN, Irapuato, Mexico
| | - Jennifer A Steen
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Nicolas E Zaragoza
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Glenn Moonen
- Zoetis, 45 Poplar Road, Parkville, VIC 3052, Australia
| | | | - Mark P Hodson
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; Metabolomics Australia Queensland Node, AIBN, The University of Queensland, Brisbane, QLD 4072, Australia
| | - John Power
- Zoetis, 45 Poplar Road, Parkville, VIC 3052, Australia
| | - Lars K Nielsen
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia.
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13
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Scalfaro C, Iacobino A, Grande L, Morabito S, Franciosa G. Effects of Megaplasmid Loss on Growth of Neurotoxigenic Clostridium butyricum Strains and Botulinum Neurotoxin Type E Expression. Front Microbiol 2016; 7:217. [PMID: 26941734 PMCID: PMC4766289 DOI: 10.3389/fmicb.2016.00217] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/10/2016] [Indexed: 11/13/2022] Open
Abstract
Clostridium butyricum strains that atypically produce the botulinum neurotoxin type E (BoNT/E) possess a megaplasmid of unknown functions in their genome. In this study, we cured two botulinum neurotoxigenic C. butyricum type E strains of their megaplasmids, and compared the obtained megaplasmid-cured strains to their respective wild-type parental strains. Our results showed that the megaplasmids do not confer beta-lactam resistance on the neurotoxigenic C. butyricum type E strains, although they carry several putative beta-lactamase genes. Instead, we found that the megaplasmids are essential for growth of the neurotoxigenic C. butyricum type E strains at the relatively low temperature of 15°C, and are also relevant for growth of strains under limiting pH and salinity conditions, as well as under favorable environmental conditions. Moreover, the presence of the megaplasmids was associated with increased transcript levels of the gene encoding BoNT/E in the C. butyricum type E strains, indicating that the megaplasmids likely contain transcriptional regulators. However, the levels of BoNT/E in the supernatants of the cured and uncured strains were similar after 24 and 48 h culture, suggesting that expression of BoNT/E in the C. butyricum type E strains is not ultimately controlled by the megaplasmids. Together, our results reveal that the C. butyricum type E megaplasmids exert pleiotropic effects on the growth of their microbial hosts under optimal and limiting environmental conditions, and also highlight the possibility of original regulatory mechanisms controlling the expression of BoNT/E.
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Affiliation(s)
- Concetta Scalfaro
- Unit of Foodborne Zoonoses, Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità Rome, Italy
| | - Angelo Iacobino
- Unit of Foodborne Zoonoses, Department of Food Safety and Veterinary Public Health, Istituto Superiore di SanitàRome, Italy; Unit of Systemic Bacterial Infections, Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di SanitàRome, Italy
| | - Laura Grande
- Unit of Foodborne Zoonoses, Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità Rome, Italy
| | - Stefano Morabito
- Unit of Foodborne Zoonoses, Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità Rome, Italy
| | - Giovanna Franciosa
- Unit of Foodborne Zoonoses, Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità Rome, Italy
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14
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Genetic diversity within the botulinum neurotoxin-producing bacteria and their neurotoxins. Toxicon 2015; 107:2-8. [PMID: 26368006 DOI: 10.1016/j.toxicon.2015.09.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 08/27/2015] [Accepted: 09/08/2015] [Indexed: 12/25/2022]
Abstract
The recent availability of multiple Clostridium botulinum genomic sequences has initiated a new genomics era that strengthens our understanding of the bacterial species that produce botulinum neurotoxins (BoNTs). Analysis of the genomes has reinforced the historical Group I-VI designations and provided evidence that the bont genes can be located within the chromosome, phage or plasmids. The sequences provide the opportunity to examine closely the variation among the toxin genes, the composition and organization of the toxin complex, the regions flanking the toxin complex and the location of the toxin within different bacterial strains. These comparisons provide evidence of horizontal gene transfer and site-specific insertion and recombination events that have contributed to the variation observed among the neurotoxins. Here, examples that have contributed to the variation observed in serotypes A-H strains are presented to illustrate the mechanisms that have contributed to their variation.
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15
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Rummel A. The long journey of botulinum neurotoxins into the synapse. Toxicon 2015; 107:9-24. [PMID: 26363288 DOI: 10.1016/j.toxicon.2015.09.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 08/27/2015] [Accepted: 09/08/2015] [Indexed: 01/09/2023]
Abstract
Botulinum neurotoxins (BoNT) cause the disease botulism, a flaccid paralysis of the muscle. They are also very effective, widely used medicines applied locally in sub-nanogram quantities. BoNTs are released together with several non-toxic, associated proteins as progenitor toxin complexes (PCT) by Clostridium botulinum to become highly potent oral poisons ingested via contaminated food. They block the neurotransmission in susceptible animals and humans already in nanogram quantities due to their specific ability to enter motoneurons and to cleave only selected neuronal proteins involved in neuroexocytosis. BoNTs have developed a sophisticated strategy to passage the gastrointestinal tract and to be absorbed in the intestine of the host to finally attack neurons. A non-toxic non-hemagglutinin (NTNHA) forms a binary complex with BoNT to protect it from gastrointestinal degradation. This binary M-PTC is one component of the bi-modular 14-subunit ∼760 kDa large progenitor toxin complex. The other component is the structurally and functionally independent dodecameric hemagglutinin (HA) complex which facilitates the absorption on the intestinal epithelium by glycan binding. Subsequent to its transcytosis the HA complex disrupts the tight junction of the intestinal barrier from the basolateral side by binding to E-cadherin. Now, the L-PTC can also enter the circulation by paracellular routes in much larger quantities. From here, the dissociated BoNTs reach the neuromuscular junction and accumulate via interaction with polysialo gangliosides, complex glycolipids, on motoneurons at the neuromuscular junction. Subsequently, additional specific binding to luminal segments of synaptic vesicles proteins like SV2 and synaptotagmin leads to their uptake. Finally, the neurotoxins shut down the synaptic vesicle cycle, which they had exploited before to enter their target cells, via specific cleavage of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, which constitute the core components of the cellular membrane fusion machinery.
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Affiliation(s)
- Andreas Rummel
- Institut für Toxikologie, Medizinische Hochschule Hannover, 30623 Hannover, Germany.
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16
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Connan C, Popoff MR. Two-component systems and toxinogenesis regulation in Clostridium botulinum. Res Microbiol 2015; 166:332-43. [PMID: 25592073 DOI: 10.1016/j.resmic.2014.12.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 12/22/2014] [Accepted: 12/23/2014] [Indexed: 12/15/2022]
Abstract
Botulinum neurotoxins (BoNTs) are the most potent toxins ever known. They are mostly produced by Clostridium botulinum but also by other clostridia. BoNTs associate with non-toxic proteins (ANTPs) to form complexes of various sizes. Toxin production is highly regulated through complex networks of regulatory systems involving an alternative sigma factor, BotR, and at least 6 recently described two-component systems (TCSs). TCSs allow bacteria to sense environmental changes and to respond to various stimuli by regulating the expression of specific genes at a transcriptional level. Several environmental stimuli have been identified to positively or negatively regulate toxin synthesis; however, the link between environmental stimuli and TCSs is still elusive. This review aims to highlight the role of TCSs as a central point in the regulation of toxin production in C. botulinum.
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Affiliation(s)
- Chloé Connan
- Institut Pasteur, Unité des Bactéries anaérobies et Toxines, Paris, France
| | - Michel R Popoff
- Institut Pasteur, Unité des Bactéries anaérobies et Toxines, Paris, France.
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Abstract
Since the first application of high hydrostatic pressure (HHP) for food preservation more than 100 years ago, a wealth of knowledge has been gained on molecular mechanisms underlying the HHP-mediated destruction of microorganisms. However, one observation made back then is still valid, i.e. that HHP alone is not sufficient for the complete inactivation of bacterial endospores. To achieve "commercial sterility" of low-acid foods, i.e. inactivation of spores capable of growing in a specific product under typical storage conditions, a combination of HHP with other hurdles is required (most effectively with heat (HPT)). Although HPT processes are not yet industrially applied, continuous technical progress and increasing consumer demand for minimally processed, additive-free food with long shelf life, makes HPT sterilization a promising alternative to thermal processing.In recent years, considerable progress has been made in understanding the response of spores of the model organism B. subtilis to HPT treatments and detailed insights into some basic mechanisms in Clostridium species shed new light on differences in the HPT-mediated inactivation of Bacillus and Clostridium spores. In this chapter, current knowledge on sporulation and germination processes, which presents the basis for understanding development and loss of the extreme resistance properties of spores, is summarized highlighting commonalities and differences between Bacillus and Clostridium species. In this context, the effect of HPT treatments on spores, inactivation mechanism and kinetics, the role of population heterogeneity, and influence factors on the results of inactivation studies are discussed.
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Affiliation(s)
- Christian A Lenz
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, 85354, Freising, Germany
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18
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Abstract
Plasmid-encoded virulence factors are important in the pathogenesis of diseases caused by spore-forming bacteria. Unlike many other bacteria, the most common virulence factors encoded by plasmids in Clostridium and Bacillus species are protein toxins. Clostridium perfringens causes several histotoxic and enterotoxin diseases in both humans and animals and produces a broad range of toxins, including many pore-forming toxins such as C. perfringens enterotoxin, epsilon-toxin, beta-toxin, and NetB. Genetic studies have led to the determination of the role of these toxins in disease pathogenesis. The genes for these toxins are generally carried on large conjugative plasmids that have common core replication, maintenance, and conjugation regions. There is considerable functional information available about the unique tcp conjugation locus carried by these plasmids, but less is known about plasmid maintenance. The latter is intriguing because many C. perfringens isolates stably maintain up to four different, but closely related, toxin plasmids. Toxin genes may also be plasmid-encoded in the neurotoxic clostridia. The tetanus toxin gene is located on a plasmid in Clostridium tetani, but the botulinum toxin genes may be chromosomal, plasmid-determined, or located on bacteriophages in Clostridium botulinum. In Bacillus anthracis it is well established that virulence is plasmid determined, with anthrax toxin genes located on pXO1 and capsule genes on a separate plasmid, pXO2. Orthologs of these plasmids are also found in other members of the Bacillus cereus group such as B. cereus and Bacillus thuringiensis. In B. thuringiensis these plasmids may carry genes encoding one or more insecticidal toxins.
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Anniballi F, Lonati D, Fiore A, Auricchio B, De Medici D, Locatelli CA. New targets in the search for preventive and therapeutic agents for botulism. Expert Rev Anti Infect Ther 2014; 12:1075-86. [PMID: 25089560 DOI: 10.1586/14787210.2014.945917] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Botulism is a severe neuroparalytic disease resulting from exposure to one of the most poisonous toxins to humans. Because of this high potency and the use of toxins as biological weapons, botulism is a public health concern and each case represents an emergency. Current therapy involves respiratory supportive care and anti-toxins administration. As a preventive measure, vaccination against toxins represents an effective strategy but is undesirable due the rarity of botulism and the effectiveness of toxins in treating several neuromuscular disorders. This paper summarizes the current issues in botulism treatment and prevention, highlighting the challenge for future researches.
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Affiliation(s)
- Fabrizio Anniballi
- Department of Veterinary Public Health and Food Safety, National Reference Centre for Botulism, Istituto Superiore di Sanità, Viale Regina Elena, 299 - 00161 Rome, Italy
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Production of recombinant botulism antigens: A review of expression systems. Anaerobe 2014; 28:130-6. [DOI: 10.1016/j.anaerobe.2014.06.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 06/03/2014] [Accepted: 06/03/2014] [Indexed: 11/18/2022]
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