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Masquelier J, Segers C, Jacobs B, Van Nieuwenhuysen T, Delbrassinne L, Van Hoeck E. Validation of a Targeted LC-MS/MS Method for Cereulide and Application in Food and Faeces. Toxins (Basel) 2023; 16:13. [PMID: 38251230 PMCID: PMC10819378 DOI: 10.3390/toxins16010013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/11/2023] [Accepted: 12/21/2023] [Indexed: 01/23/2024] Open
Abstract
Cereulide is an emetic toxin produced by some strains of Bacillus cereus. This bacterial toxin, a cyclic 1.2 kDa dodecadepsipeptide, is stable to heat and acids and causes nausea and vomiting when ingested via contaminated food. This work aimed to develop and validate a targeted analytical method applying liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify this toxin in food and human faeces. Samples were extracted with acetonitrile in the presence of 13C6-cereulide, a labelled internal standard, and purified by centrifugation and filtration. The limits of quantification were 0.5 and 0.3 µg kg-1 for food and faeces, respectively. The linearity of the method was very good, with calculated R2 values above 0.995. The mean recovery of the method was within the acceptable range of 70.0%-120.0%, the repeatability was not higher than 7.3%, and the highest intra-laboratory reproducibility was 8.9%. The estimated range for the expanded measurement uncertainty was between 5.1% and 18.0%. The LC-MS/MS method was used to analyse one food sample (rice) from a Belgian foodborne outbreak and five faecal samples from patients with clinical symptoms after consumption of the contaminated rice. The levels of cereulide were 12.22 µg g-1 for food and between 6.32 and 773.37 ng g-1 for faecal samples.
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Affiliation(s)
- Julien Masquelier
- Organic Contaminants and Additives, Sciensano, Scientific Institute of Public Health, 1050 Brussels, Belgium
| | - Céline Segers
- Organic Contaminants and Additives, Sciensano, Scientific Institute of Public Health, 1050 Brussels, Belgium
| | - Bram Jacobs
- Food Pathogens, Sciensano, Scientific Institute of Public Health, 1050 Brussels, Belgium
| | - Tom Van Nieuwenhuysen
- Food Pathogens, Sciensano, Scientific Institute of Public Health, 1050 Brussels, Belgium
| | - Laurence Delbrassinne
- Food Pathogens, Sciensano, Scientific Institute of Public Health, 1050 Brussels, Belgium
| | - Els Van Hoeck
- Organic Contaminants and Additives, Sciensano, Scientific Institute of Public Health, 1050 Brussels, Belgium
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2
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Jenull S, Bauer T, Silbermayr K, Dreer M, Stark TD, Ehling-Schulz M. The toxicological spectrum of the Bacillus cereus toxin cereulide points towards niche-specific specialisation. Environ Microbiol 2023; 25:2231-2249. [PMID: 37354053 DOI: 10.1111/1462-2920.16454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 06/06/2023] [Indexed: 06/26/2023]
Abstract
Most microbes share their environmental niches with very different forms of life thereby engaging in specialised relationships to enable their persistence. The bacterium Bacillus cereus occurs ubiquitously in the environment with certain strain backgrounds causing foodborne and opportunistic infections in humans. The emetic lineage of B. cereus is capable of producing the toxin cereulide, which evokes emetic illnesses. Although food products favouring the accumulation of cereulide are known, the ecological role of cereulide and the environmental niche of emetic B. cereus remain elusive. To better understand the ecology of cereulide-producing B. cereus, we systematically assayed the toxicological spectrum of cereulide on a variety of organisms belonging to different kingdoms. As cereulide is a potassium ionophore, we further tested the effect of environmental potassium levels on the action of cereulide. We found that adverse effects of cereulide exposure are species-specific, which can be exacerbated with increased environmental potassium. Additionally, we demonstrate that cereulide is produced within an insect cadaver indicating its potential ecological function for a saprophytic lifestyle. Collectively, distinct cereulide susceptibilities of other organisms may reflect its role in enabling competitive niche specialization of emetic B. cereus.
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Affiliation(s)
- Sabrina Jenull
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Tobias Bauer
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Katja Silbermayr
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Maximilian Dreer
- Department of Functional and Evolutionary Ecology, Archaea Biology and Ecogenomics Unit, University of Vienna, Vienna, Austria
| | - Timo D Stark
- Food Chemistry and Molecular Sensory Science, Technical University of Munich, Freising, Germany
| | - Monika Ehling-Schulz
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
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3
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Hu R, Hu A, Lu Z, Zhou H, Wei W, Lu F, Zhao H, Bie X. Construction and optimization of a multiplex PMAxx-qPCR assay for viable Bacillus cereus and development of a detection kit. J Microbiol Methods 2023; 207:106705. [PMID: 36914099 DOI: 10.1016/j.mimet.2023.106705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 03/09/2023] [Accepted: 03/09/2023] [Indexed: 03/13/2023]
Abstract
In this study, a PMAxx-qPCR method for the detection and quantification of viable Bacillus cereus (B. cereus) was established based on the cesA gene that is involved in cereulide synthesis, enterotoxin gene bceT and hemolytic enterotoxin gene hblD combined with modified propidium monoazide (PMAxx). The sensitivity detection limit of the method was as follows: the DNA extracted by the kit reached 140 fg/μL, and the bacterial suspension without enrichment reached 2.24 × 101 CFU/mL; 14 nonB. cereus strains of the 17 tested strains all tested as negative, whereas the 2 strains of B. cereus carrying the target virulence gene(s) could be accurately detected. In terms of application, we assembled the constructed PMAxx-qPCR reaction into a detection kit and evaluated its application performance. The results showed that the detection kit has high sensitivity, strong anti-interference capability, and has good application potential. The purpose of this study is to provide a reliable detection method for the prevention and traceability of B. cereus infections.
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Affiliation(s)
- Ruirui Hu
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Xuanwu District, Nanjing, Jiangsu, China
| | - Antuo Hu
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Xuanwu District, Nanjing, Jiangsu, China
| | - Zhaoxin Lu
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Xuanwu District, Nanjing, Jiangsu, China
| | - Haibo Zhou
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Xuanwu District, Nanjing, Jiangsu, China
| | - Wanqing Wei
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Xuanwu District, Nanjing, Jiangsu, China
| | - Fengxia Lu
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Xuanwu District, Nanjing, Jiangsu, China
| | - Haizhen Zhao
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Xuanwu District, Nanjing, Jiangsu, China
| | - Xiaomei Bie
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Xuanwu District, Nanjing, Jiangsu, China.
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Yang S, Wang Y, Liu Y, Jia K, Zhang Z, Dong Q. Cereulide and Emetic Bacillus cereus: Characterizations, Impacts and Public Precautions. Foods 2023; 12:foods12040833. [PMID: 36832907 PMCID: PMC9956921 DOI: 10.3390/foods12040833] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/10/2023] [Accepted: 02/12/2023] [Indexed: 02/18/2023] Open
Abstract
Cereulide, which can be produced by Bacillus cereus, is strongly associated with emetic-type food poisoning outbreaks. It is an extremely stable emetic toxin, which is unlikely to be inactivated by food processing. Considering the high toxicity of cereulide, its related hazards raise public concerns. A better understanding of the impact of B. cereus and cereulide is urgently needed to prevent contamination and toxin production, thereby protecting public health. Over the last decade, a wide range of research has been conducted regarding B. cereus and cereulide. Despite this, summarized information highlighting precautions at the public level involving the food industry, consumers and regulators is lacking. Therefore, the aim of the current review is to summarize the available data describing the characterizations and impacts of emetic B. cereus and cereulide; based on this information, precautions at the public level are proposed.
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Cereulide and Deoxynivalenol Increase LC3 Protein Levels in HepG2 Liver Cells. Toxins (Basel) 2022; 14:toxins14020151. [PMID: 35202179 PMCID: PMC8880806 DOI: 10.3390/toxins14020151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 02/14/2022] [Indexed: 02/05/2023] Open
Abstract
Food contaminants of bacterial or fungal origin frequently contaminate staple foods to various extents. Among others, the bacterial toxin cereulide (CER) and the mycotoxin deoxynivalenol (DON) co-occur in a mixed diet and are absorbed by the human body. Both toxins exert dis-tinctive mitotoxic potential. As damaged mitochondria are removed via autophagy, mitochondrial and lysosomal toxicity were assessed by applying low doses of single and combined toxins (CER 0.1-50 ng/mL; DON 0.01-5 µg/mL) to HepG2 liver cells. In addition to cytotoxicity assays, RT-qPCR was performed to investigate genes involved in lysosomal biogenesis and autophagy. CER and DON caused significant cytotoxicity on HepG2 cells after 5 and 24 h over a broad concentration range. CER, alone and in combination with DON, increased the transcription of the autophagy related genes coding for the microtubule associated protein 1A/1B light chain 3 (LC3) and sequestome 1 (SQSTM1) as well as LC3 protein expression which was determined using immunocytochemistry. DON increased LC3 protein expression without induction of gene transcription, hence it seems plausible that CER and DON act on different pathways. The results support the hypothesis that CER induces autophagy via the LC3 pathway and damaged mitochondria are therefore eliminated.
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Bacillus cereus Toxin Repertoire: Diversity of (Iso)cereulide(s). MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030872. [PMID: 35164132 PMCID: PMC8840689 DOI: 10.3390/molecules27030872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/14/2022] [Accepted: 01/19/2022] [Indexed: 11/17/2022]
Abstract
The emetic Bacillus cereus toxin cereulide (1) poses a significant safety risk in the food industry, causing emesis and nausea after consumption of contaminated foods. Analogously to cereulide, the structures of various isocereulides, namely, isocereulides A–G, have been recently reported and could also be identified in B. cereus-contaminated food samples. The HPLC fractionation of B. cereus extracts allows us to isolate additional isocereulides. By applying MSn sequencing, post-hydrolytic dipeptide, amino acid and α-hydroxy acid analyses using UPLC-ESI-TOF-MS to purify the analytes, seven new isocereulides H–N (2–8) could be elucidated in their chemical structures. The structure elucidation was supported by one-dimensional and two-dimensional NMR spectra of the isocereulides H (2), K (5), L and N (6 + 8) and M (7). The toxicity of 2–8 was investigated in a HEp-2 cell assay to determine their respective 50% effective concentration (EC50). Thus, 2–8 exhibited EC50 values ranging from a 0.4- to 1.4-fold value compared to cereulide (1). Missing structure-activity correlations indicate the necessity to determine the toxic potential of all naturally present isocereulides as single compounds to be able to perform a thorough toxicity evaluation of B. cereus-contaminated foods in the future.
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Zhou H, Zhang J, Shao Y, Wang J, Xu W, Liu Y, Yu S, Ye Q, Pang R, Wu S, Gu Q, Xue L, Zhang J, Li H, Wu Q, Ding Y. Development of a high resolution melting method based on a novel molecular target for discrimination between Bacillus cereus and Bacillus thuringiensis. Food Res Int 2022; 151:110845. [PMID: 34980383 DOI: 10.1016/j.foodres.2021.110845] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 11/03/2021] [Accepted: 11/27/2021] [Indexed: 11/04/2022]
Abstract
Delimitation within the Bacillus cereus group is confusing due to the highly similar genetic background of its constituent bacteria. This study aimed to develop a rapid and efficient method for the identification of Bacillus cereus and Bacillus thuringiensis, two closely related species within the B. cereus group. Using average nucleotide identity analysis (ANI) and ribosomal multilocus sequence typing (rMLST), the authenticity of the genomes of B. cereus and B. thuringiensis was determined. Emetic B. cereus and Bacillus bombysepticus were also included to provide novel genomic insights into the boundaries within the B. cereus group. Using pan-genome analysis, ispD, a novel core and single-copy molecular target, was identified for the differentiation between B. cereus and B. thuringiensis. Based on the single nucleotide polymorphism within ispD, a high resolution melting (HRM) method for the determination of B. cereus and B. thuringiensis was developed. This method can not only distinguish B. cereus and B. thuringiensis, but can also separate B. cereus from other foodborne pathogenic bacteria. The detection limit of this method could reach 1 pg of pure genomic DNA and 3.7 × 102 cfu/mL of pure culture. Moreover, this new method could effectively differentiate B. cereus and B. thuringiensis in spiked, mixed, and real food samples. Collectively, the established HRM method can provide a new reference paradigm for the sensitive and specific nucleic acid detection of pathogens with identical genomes.
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Affiliation(s)
- Huan Zhou
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Junhui Zhang
- Department of Food Science & Technology, Institute of Food Safety & Nutrition, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Yanna Shao
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China; Department of Food Science & Technology, Institute of Food Safety & Nutrition, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Juan Wang
- College of Food Science, South China Agricultural University, Guangzhou 510432, China
| | - Wenxing Xu
- Department of Food Science & Technology, Institute of Food Safety & Nutrition, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Yang Liu
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Shubo Yu
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Qinghua Ye
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Rui Pang
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Shi Wu
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Qihui Gu
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Liang Xue
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Jumei Zhang
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Hongye Li
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Qingping Wu
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Yu Ding
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China; Department of Food Science & Technology, Institute of Food Safety & Nutrition, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
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Thery M, Cousin VL, Tissieres P, Enault M, Morin L. Multi-organ failure caused by lasagnas: A case report of Bacillus cereus food poisoning. Front Pediatr 2022; 10:978250. [PMID: 36186625 PMCID: PMC9516094 DOI: 10.3389/fped.2022.978250] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 08/08/2022] [Indexed: 11/17/2022] Open
Abstract
We report a Bacillus cereus, cereulide producing strain, food poisoning of two sisters. After eating a few bites of pasta cooked 3 days earlier, a 13-year-old girl developed mild symptoms. However, her 11-year-old sister suffered, 40 h after ingestion of the entire platter, a multi-organ failure including acute liver failure, rhabdomyolysis, disseminated intravascular coagulation, and acute kidney injury (AKI). She received supportive care in pediatric intensive care using mechanical ventilation, hemofiltration, and high-doses vasopressors. She was specifically treated for toxin-mediated disease using blood purification and further digestive decontamination. This report highlights the potential severity of B. cereus food poisoning but also a successful dual treatment including toxin removal and antimicrobial treatment to prevent toxin production.
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Affiliation(s)
- Marin Thery
- Pediatric and Neonatal Intensive Care Unit, DMU 3 Santé de L'enfant et de l'Adolescent, Assistance Publique-Hôpitaux de Paris Paris Saclay, Bicêtre Hospital, Le Kremlin-Bicêtre, France
| | - Vladimir L Cousin
- Pediatric and Neonatal Intensive Care Unit, DMU 3 Santé de L'enfant et de l'Adolescent, Assistance Publique-Hôpitaux de Paris Paris Saclay, Bicêtre Hospital, Le Kremlin-Bicêtre, France.,Pediatric Intensive Care Unit, Département de la Femme, de l'Enfant et de l'Adolescent, Hôpitaux Universitaires de Genève, Genève, Switzerland
| | - Pierre Tissieres
- Pediatric and Neonatal Intensive Care Unit, DMU 3 Santé de L'enfant et de l'Adolescent, Assistance Publique-Hôpitaux de Paris Paris Saclay, Bicêtre Hospital, Le Kremlin-Bicêtre, France.,Institute of Integrative Biology of the Cell, CNRS, CEA, Paris Saclay University, Gif-sur-Yvette, France
| | - Maxime Enault
- Assistance Publique-Hôpitaux de Paris, Pediatric Emergency Department, Armand Trousseau University Hospital, Sorbonne Université, Paris, France
| | - Luc Morin
- Pediatric and Neonatal Intensive Care Unit, DMU 3 Santé de L'enfant et de l'Adolescent, Assistance Publique-Hôpitaux de Paris Paris Saclay, Bicêtre Hospital, Le Kremlin-Bicêtre, France.,Institute of Integrative Biology of the Cell, CNRS, CEA, Paris Saclay University, Gif-sur-Yvette, France
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9
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Emetic toxin production of Bacillus cereus in a biofilm. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2021.112840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Jovanovic J, Ornelis VFM, Madder A, Rajkovic A. Bacillus cereus food intoxication and toxicoinfection. Compr Rev Food Sci Food Saf 2021; 20:3719-3761. [PMID: 34160120 DOI: 10.1111/1541-4337.12785] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 05/13/2021] [Accepted: 05/15/2021] [Indexed: 12/12/2022]
Abstract
Bacillus cereus is one of the leading etiological agents of toxin-induced foodborne diseases. Its omnipresence in different environments, spore formation, and its ability to adapt to varying conditions and produce harmful toxins make this pathogen a health hazard that should not be underestimated. Food poisoning by B. cereus can manifest itself as an emetic or diarrheal syndrome. The former is caused by the release of the potent peptide toxin cereulide, whereas the latter is the result of proteinaceous enterotoxins (e.g., hemolysin BL, nonhemolytic enterotoxin, and cytotoxin K). The final harmful effect is not only toxin and strain dependent, but is also affected by the stress responses, accessory virulence factors, and phenotypic properties under extrinsic, intrinsic, and explicit food conditions and host-related environment. Infamous portrait of B. cereus as a foodborne pathogen, as well as a causative agent of nongastrointestinal infections and even nosocomial complications, has inspired vast volumes of multidisciplinary research in food and clinical domains. As a result, extensive original data became available asking for a new, both broad and deep, multifaceted look into the current state-of-the art regarding the role of B. cereus in food safety. In this review, we first provide an overview of the latest knowledge on B. cereus toxins and accessory virulence factors. Second, we describe the novel taxonomy and some of the most pertinent phenotypic characteristics of B. cereus related to food safety. We link these aspects to toxin production, overall pathogenesis, and interactions with its human host. Then we reflect on the prevalence of different toxinotypes in foods opening the scene for epidemiological aspects of B. cereus foodborne diseases and methods available to prevent food poisoning including overview of the different available methods to detect B. cereus and its toxins.
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Affiliation(s)
- Jelena Jovanovic
- Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Vincent F M Ornelis
- Department of Organic and Macromolecular Chemistry, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Annemieke Madder
- Department of Organic and Macromolecular Chemistry, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Andreja Rajkovic
- Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Zhong W, Shahbaz O, Teskey G, Beever A, Kachour N, Venketaraman V, Darmani NA. Mechanisms of Nausea and Vomiting: Current Knowledge and Recent Advances in Intracellular Emetic Signaling Systems. Int J Mol Sci 2021; 22:5797. [PMID: 34071460 PMCID: PMC8198651 DOI: 10.3390/ijms22115797] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/20/2021] [Accepted: 05/21/2021] [Indexed: 02/07/2023] Open
Abstract
Nausea and vomiting are common gastrointestinal complaints that can be triggered by diverse emetic stimuli through central and/or peripheral nervous systems. Both nausea and vomiting are considered as defense mechanisms when threatening toxins/drugs/bacteria/viruses/fungi enter the body either via the enteral (e.g., the gastrointestinal tract) or parenteral routes, including the blood, skin, and respiratory systems. While vomiting is the act of forceful removal of gastrointestinal contents, nausea is believed to be a subjective sensation that is more difficult to study in nonhuman species. In this review, the authors discuss the anatomical structures, neurotransmitters/mediators, and corresponding receptors, as well as intracellular emetic signaling pathways involved in the processes of nausea and vomiting in diverse animal models as well as humans. While blockade of emetic receptors in the prevention of vomiting is fairly well understood, the potential of new classes of antiemetics altering postreceptor signal transduction mechanisms is currently evolving, which is also reviewed. Finally, future directions within the field will be discussed in terms of important questions that remain to be resolved and advances in technology that may help provide potential answers.
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Affiliation(s)
- Weixia Zhong
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 East Second Street, Pomona, CA 91766, USA; (W.Z.); (G.T.); (V.V.)
| | - Omar Shahbaz
- School of Medicine, Universidad Iberoamericana, Av. Francia 129, Santo Domingo 10203, Dominican Republic;
| | - Garrett Teskey
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 East Second Street, Pomona, CA 91766, USA; (W.Z.); (G.T.); (V.V.)
| | - Abrianna Beever
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA; (A.B.); (N.K.)
| | - Nala Kachour
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA; (A.B.); (N.K.)
| | - Vishwanath Venketaraman
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 East Second Street, Pomona, CA 91766, USA; (W.Z.); (G.T.); (V.V.)
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA; (A.B.); (N.K.)
| | - Nissar A. Darmani
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 East Second Street, Pomona, CA 91766, USA; (W.Z.); (G.T.); (V.V.)
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12
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Assay of Bacillus cereus Emetic toxin produced in orange squash. EUREKA: LIFE SCIENCES 2021. [DOI: 10.21303/2504-5695.2021.001753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The contamination of squash by B. cereus, an enterotoxin producer, was found to range between 7.5×104 and 1.8×104 CFU/g in orange squash (during storage), that is hazardous. Orange squash is widely produced and consumed in India, but has a low rating of 3 on the scale of 10 (on feedback), mostly due to high sugars, not preferred these days. It can be preserved for >9 months due to added sugars and preservatives. During processing squash, if juice is not quickly cooled and/or squash is kept for long at temperatures <48 °C after processing, it can be a source of food poisoning. Reason, a large number of toxins can be produced by B. cereus. B. cereus strains, isolated from squash, produce heat stable toxin. Vacuolar assay confirmed them as emetic toxins, produced in squash. The toxin behaved like an ionophore in assay using mitochondria, extracted from liver cells of chicken with potassium ions in buffer. The toxicity of toxin by assay was 3200 IU/ng (BC IV strain) and 800 IU/ng (BC X strain). By the vacuolar expansions of mitochondria in assay, toxins of B. cereus demonstrated a toxic effect, in the range of 20.93 to 60.94 % by BC IV toxin and 43.28 to 45.02 % by BC X toxin, on the 3rd day growth of B. cereus in squash and toxin extraction for assay. It was also possible to produce antibodies against the B. cereus whole cell and toxin of BC IV, as an attempt to detect B. cereus contaminations in foods, by Ouchterlony’s immune-diffusion test
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The Food Poisoning Toxins of Bacillus cereus. Toxins (Basel) 2021; 13:toxins13020098. [PMID: 33525722 PMCID: PMC7911051 DOI: 10.3390/toxins13020098] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/14/2021] [Accepted: 01/25/2021] [Indexed: 12/13/2022] Open
Abstract
Bacillus cereus is a ubiquitous soil bacterium responsible for two types of food-associated gastrointestinal diseases. While the emetic type, a food intoxication, manifests in nausea and vomiting, food infections with enteropathogenic strains cause diarrhea and abdominal pain. Causative toxins are the cyclic dodecadepsipeptide cereulide, and the proteinaceous enterotoxins hemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe) and cytotoxin K (CytK), respectively. This review covers the current knowledge on distribution and genetic organization of the toxin genes, as well as mechanisms of enterotoxin gene regulation and toxin secretion. In this context, the exceptionally high variability of toxin production between single strains is highlighted. In addition, the mode of action of the pore-forming enterotoxins and their effect on target cells is described in detail. The main focus of this review are the two tripartite enterotoxin complexes Hbl and Nhe, but the latest findings on cereulide and CytK are also presented, as well as methods for toxin detection, and the contribution of further putative virulence factors to the diarrheal disease.
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Jessberger N, Dietrich R, Granum PE, Märtlbauer E. The Bacillus cereus Food Infection as Multifactorial Process. Toxins (Basel) 2020; 12:E701. [PMID: 33167492 PMCID: PMC7694497 DOI: 10.3390/toxins12110701] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 10/30/2020] [Accepted: 11/02/2020] [Indexed: 02/06/2023] Open
Abstract
The ubiquitous soil bacterium Bacillus cereus presents major challenges to food safety. It is responsible for two types of food poisoning, the emetic form due to food intoxication and the diarrheal form emerging from food infections with enteropathogenic strains, also known as toxico-infections, which are the subject of this review. The diarrheal type of food poisoning emerges after production of enterotoxins by viable bacteria in the human intestine. Basically, the manifestation of the disease is, however, the result of a multifactorial process, including B. cereus prevalence and survival in different foods, survival of the stomach passage, spore germination, motility, adhesion, and finally enterotoxin production in the intestine. Moreover, all of these processes are influenced by the consumed foodstuffs as well as the intestinal microbiota which have, therefore, to be considered for a reliable prediction of the hazardous potential of contaminated foods. Current knowledge regarding these single aspects is summarized in this review aiming for risk-oriented diagnostics for enteropathogenic B. cereus.
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Affiliation(s)
- Nadja Jessberger
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany; (R.D.); (E.M.)
| | - Richard Dietrich
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany; (R.D.); (E.M.)
| | - Per Einar Granum
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, P.O. Box 5003 NMBU, 1432 Ås, Norway;
| | - Erwin Märtlbauer
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany; (R.D.); (E.M.)
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15
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Beyond Toxin Transport: Novel Role of ABC Transporter for Enzymatic Machinery of Cereulide NRPS Assembly Line. mBio 2020; 11:mBio.01577-20. [PMID: 32994334 PMCID: PMC7527721 DOI: 10.1128/mbio.01577-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
This study revealed a novel, potentially conserved mechanism involved in the biosynthesis of microbial natural products, exemplified by the mitochondrial active depsipeptide cereulide. Similar to other bioactive substances, such as the last-resort antibiotics vancomycin and daptomycin, the antitumor drug cryptophycin or the cholesterol-lowering agent lovastatin, cereulide is synthesized nonribosomally by multienzyme machinery, requiring the concerted actions of multiple proteins to ensure correct product assembly. Given the importance of microbial secondary metabolites in human and veterinary medicine, it is critical to understand how these processes are orchestrated within the host cells. By revealing that tethering of a biosynthetic enzyme to the cell membrane by an ABC transporter is essential for nonribosomal peptide production, our study provides novel insights into synthesis of microbial secondary metabolites, which could contribute to isolation of novel compounds from cryptic secondary metabolite clusters or improve the yield of produced pharmaceuticals. Nonribosomal peptide synthetases (NRPSs) and polyketide synthetases (PKSs) play a pivotal role in the production of bioactive natural products, such as antibiotics and cytotoxins. Despite biomedical and pharmaceutical importance, the molecular mechanisms and architectures of these multimodular enzyme complexes are not fully understood. Here, we report on an ABC transporter that forms a vital part of the nonribosomal peptide biosynthetic machinery. Emetic Bacillus cereus produces the highly potent, mitochondrial active nonribosomal depsipeptide cereulide, synthesized by the NRPS Ces. The ces gene locus includes, next to the structural cesAB genes, a putative ABC transporter, designated cesCD. Our study demonstrates that tethering of CesAB synthetase to the cell membrane by CesCD is critical for peptide assembly. In vivo studies revealed that CesAB colocalizes with CesCD on the cell membrane, suggesting direct involvement of this ABC transporter in the biosynthesis of a nonribosomal peptide. Mutation of cesCD, disrupting the assembly of the CesCD complex, resulted in decreased interaction with CesAB and, as a consequence, negatively affected cereulide biosynthesis. Specific domains within CesAB synthetase interacting with CesC were identified. Furthermore, we demonstrated that the structurally similar BerAB transporter from Bacillus thuringiensis complements CesCD function in cereulide biosynthesis, suggesting that the direct involvement of ABC transporter in secondary metabolite biosynthesis could be a widespread mechanism. In summary, our study revealed a novel, noncanonical function for ABC transporter, which is essential for megaenzyme functionality of NRPS. The new insights into natural product biosynthesis gained may facilitate the discovery of new metabolites with bioactive potential.
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16
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Heberlig GW, Boddy CN. Thioesterase from Cereulide Biosynthesis Is Responsible for Oligomerization and Macrocyclization of a Linear Tetradepsipeptide. JOURNAL OF NATURAL PRODUCTS 2020; 83:1990-1997. [PMID: 32519859 DOI: 10.1021/acs.jnatprod.0c00333] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cereulide is a toxic cyclic depsidodecapeptide produced in Bacillus cereus by two nonribosomal peptide synthetases, CesA and CesB. While highly similar in structure to valinomycin and with a homologous biosynthetic gene cluster, recent work suggests that cereulide is produced via a different mechanism that relies on a noncanonical coupling of two didepsipeptide-peptidyl carrier protein (PCP) bound intermediates. Ultimately this alternative mechanism generates a tetradepsipeptide-PCP bound intermediate that differs from the tetradepsipeptide-PCP intermediate predicted from canonical activity of CesA and CesB. To differentiate between the mechanisms, both tetradepsipeptides were prepared as N-acetyl cysteamine thioesters (SNAC), and the ability of the purified recombinant terminal CesB thioesterase (CesB TE) to oligomerize and macrocyclize each substrate was probed. Only the canonical substrate is converted to cereulide, ruling out the alternative mechanism. It was demonstrated that CesB TE can use related tetradepsipeptide substrates, such as the valinomycin tetradespipetide and a hybrid cereulide-valinomycin tetradepsipetide in conjunction with its native substrate to generate chimeric natural products. This work clarifies the biosynthetic origins of cereulide and provides a powerful biocatalyst to access analogues of these ionophoric natural products.
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Affiliation(s)
- Graham W Heberlig
- Department of Chemistry and Biomolecular Sciences Centre for Chemical and Synthetic Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Christopher N Boddy
- Department of Chemistry and Biomolecular Sciences Centre for Chemical and Synthetic Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
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17
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Naka T, Takaki Y, Hattori Y, Takenaka H, Ohta Y, Kirihata M, Tanimori S. Chemical structure of hydrolysates of cereulide and their time course profile. Bioorg Med Chem Lett 2020; 30:127050. [DOI: 10.1016/j.bmcl.2020.127050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/10/2020] [Accepted: 02/18/2020] [Indexed: 11/17/2022]
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18
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Combinatory effects of cereulide and deoxynivalenol on in vitro cell viability and inflammation of human Caco-2 cells. Arch Toxicol 2020; 94:833-844. [PMID: 32065293 DOI: 10.1007/s00204-020-02658-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 02/03/2020] [Indexed: 02/06/2023]
Abstract
Deoxynivalenol (DON), one of the most abundant mycotoxins in cereal products, was recently detected with other mycotoxins and the emetic bacterial toxin cereulide (CER) in maize porridge. Within a cereal-based diet, co-exposure to these toxins is likely, hence raising the question of combinatory toxicological effects. While the toxicological evaluation of DON has quite progressed, consequences of chronic, low-dose CER exposure are still insufficiently explored. Information about the combinatory toxicological effects of these toxins is lacking. In the present study, we investigated how CER (0.1-100 ng/mL) and DON (0.01-10 µg/mL) alone and in a constant ratio of 1:100 (CER:DON) affect the cytotoxicity and immune response of differentiated human intestinal Caco-2 cells. While DON alone reduced cell viability only in the highest concentration (10 µg/mL), CER caused severe cytotoxicity upon prolonged incubation (starting from 10 ng/mL after 24 h and 48 h, 2.5 ng/mL and higher after 72 h). After 72 h, synergistic effects were observed at 2.5 ng/mL CER and 0.25 µg/mL DON. Different endpoints of inflammation were investigated in interleukin-1β-stimulated Caco-2 cells. Notably, DON-induced interleukin-8 transcription and secretion were diminished by the presence of 10 and 25 ng/mL CER after short-term (5 h) incubation, indicating immunosuppressive properties. We hypothesise that habitual consumption of cereal-based foods co-contaminated with CER and DON may cause synergistic cytotoxic effects and an altered immune response in the human intestine. Therefore, further research concerning effects of co-occurring bacterial toxins and mycotoxins on the impairment of intestinal barrier integrity, intestinal inflammation and the promotion of malnutrition is needed.
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Abstract
Natural products from microorganisms are important small molecules that play roles in various biological processes like cellular growth, motility, nutrient acquisition, stress response, biofilm formation, and defense. It is hypothesized that pathogens exploit these molecules to regulate virulence and persistence during infections. Here, we present selected examples of signaling natural products from human pathogenic bacteria that use these metabolites to gain a competitive advantage. Targeting these signaling systems provides novel strategies to antimicrobial treatments.
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Affiliation(s)
- Zhijuan Hu
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, 201 Gilman Hall, Berkeley, California 94720, United States
| | - Wenjun Zhang
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, 201 Gilman Hall, Berkeley, California 94720, United States
- Chan Zuckerberg Biohub, San Francisco, California 94158, United States
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20
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Rouzeau-Szynalski K, Stollewerk K, Messelhäusser U, Ehling-Schulz M. Why be serious about emetic Bacillus cereus: Cereulide production and industrial challenges. Food Microbiol 2019; 85:103279. [PMID: 31500702 DOI: 10.1016/j.fm.2019.103279] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 07/18/2019] [Accepted: 07/25/2019] [Indexed: 01/06/2023]
Abstract
Cereulide, a potent toxin produced by Bacillus cereus, is a small, highly heat- and acid-resistant depsipeptide toxin, which confronts food industry with several challenges. Due to the ubiquitous presence of B. cereus in the environment, this opportunistic pathogen can enter food production and processing at almost any stage. Although the bacteria itself might be removed during food processing, the cereulide toxin will most likely not be destroyed or inactivated by these processes. Because of the high toxicity of cereulide and the high incidence rates often observed in connection with foodborne outbreaks, the understanding of the mechanisms of toxin production as well as accurate data on contamination sources and factors promoting toxin formation are urgently needed to prevent contamination and toxin production in food production processes. Over the last decade, considerable progress had been made on the understanding of cereulide toxin biosynthesis in emetic B. cereus, but an overview of current knowledge on this toxin with regards to food industry perspective is lacking. Thus, we aim in this work to summarize data available on extrinsic parameters acting on cereulide toxin synthesis in emetic B. cereus and to discuss the food industry specific challenges related to this toxin. Furthermore, we emphasize how identification of the cardinals in food production processes can lead to novel effective strategies for prevention of toxin formation in the food processing chain and could contribute to the improvement of existing HACCP studies.
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Affiliation(s)
| | - Katharina Stollewerk
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Austria
| | - Ute Messelhäusser
- Bavarian Health and Food Safety Authority, Veterinaerstr. 2, 85764, Oberschleissheim, Germany
| | - Monika Ehling-Schulz
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Austria.
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21
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Cui Y, Märtlbauer E, Dietrich R, Luo H, Ding S, Zhu K. Multifaceted toxin profile, an approach toward a better understanding of probiotic Bacillus cereus. Crit Rev Toxicol 2019; 49:342-356. [PMID: 31116061 DOI: 10.1080/10408444.2019.1609410] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Strains of the Bacillus cereus group have been widely used as probiotics for human beings, food animals, plants, and environmental remediation. Paradoxically, B. cereus is responsible for both gastrointestinal and nongastrointestinal syndromes and represents an important opportunistic food-borne pathogen. Toxicity assessment is a fundamental issue to evaluate safety of probiotics. Here, we summarize the state of our current knowledge about the toxins of B. cereus sensu lato to be considered for safety assessment of probiotic candidates. Surfactin-like emetic toxin (cereulide) and various enterotoxins including nonhemolytic enterotoxin, hemolysin BL, and cytotoxin K are responsible for food poisoning outbreaks characterized by emesis and diarrhea. In addition, other factors, such as hemolysin II, Certhrax, immune inhibitor A1, and sphingomyelinase, contribute to toxicity and overall virulence of B. cereus.
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Affiliation(s)
- Yifang Cui
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University , Beijing , China.,State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University , Beijing , China
| | - Erwin Märtlbauer
- Department of Veterinary Sciences, Ludwig-Maximilians-University Munich , Oberschleißheim , Germany
| | - Richard Dietrich
- Department of Veterinary Sciences, Ludwig-Maximilians-University Munich , Oberschleißheim , Germany
| | - Hailing Luo
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University , Beijing , China
| | - Shuangyang Ding
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University , Beijing , China
| | - Kui Zhu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University , Beijing , China.,National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University , Beijing , China
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22
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Removal of B. cereus cereulide toxin from monoclonal antibody bioprocess feed via two-step Protein A affinity and multimodal chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2019; 1118-1119:194-202. [PMID: 31059926 DOI: 10.1016/j.jchromb.2019.04.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 03/17/2019] [Accepted: 04/06/2019] [Indexed: 12/22/2022]
Abstract
A rapid and sensitive liquid chromatography-mass spectrometry assay was developed and used to quantify emetic cereulide peptide exotoxin, which can be related to possible Bacillus cereus contamination in monoclonal antibody (mAb) bioprocess feeds. The assay limit of detection was 0.05 ng/mL (~1 fmol injected) and limit of quantification 0.16 ng/mL (~3 fmol injected) over a standard curve with >3 orders of magnitude linear dynamic range. The assay allowed quantification of toxin removal in an established two-step mAb purification process consisting of Protein A affinity chromatography followed by multi-modal anion exchange chromatography. Toxin content was ascertained in process stream sample fractions as well as on the Protein A affinity column. An optimized analytical method allowed separation of cereulide toxin from other mAb cell culture components within 6 min. Spiking experiments showed that samples should be collected in high (80% v/v) content acetonitrile to reduce nonspecific losses of the cereulide. The majority of mAb purification process-associated cereulide was detected in the Protein A flow through fraction, whereas only residual amounts were found in wash, strip, and elution fractions. Column cleaning-in-place (CIP) procedures were evaluated to prevent carryover between affinity capture cycles. No carryover was detected between cycles, however trace amounts of cereulide were extracted from the Protein A resin. Increasing the CIP NaOH concentration from 0.1 M to 0.5 M, and contact time from 15 min to 1 h, improved removal of residual cereulide from the resin. Applicability of CIP clearance of cereulide during Protein A chromatography was confirmed with three different mAb feeds. Post Protein A polishing, via target flow through on a multi-modal anion exchange chromatography column, resulted in a product pool with no detectable cereulide. Approximately 5 logs of reduction in cereulide concentration was obtained over the two-step chromatography process. Cereulide contamination is well known and of concern in food processing, however this research may be the first LC-MS quantification of cereulide contamination, and its clearance, in biopharmaceutical mAb processing. The analytical method may also be used to rapidly screen for cereulide contamination in upstream cell culture process streams, prior to downstream product purification. This will allow appropriate measures to be taken to reduce toxin exposure to downstream bioprocess raw materials, consumables and equipment.
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23
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Hoornstra D, Andersson MA, Johansson T, Pirhonen T, Hatakka M, Salkinoja-Salonen MS. Mitochondrial Toxicity Detected in a Health Product with a Boar Spermatozoan Bioassay. Altern Lab Anim 2019; 32:407-16. [PMID: 15651926 DOI: 10.1177/026119290403200413] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Seaweed and organic alfalfa capsules sold as "health promoting" products had repeatedly caused emesis in a consumer. Using the boar spermatozoan bioassay, the capsule contents were found to contain a toxic substance that inhibited boar sperm motility and depolarised mitochondria at low exposure concentrations of 10 microg/ml. The capsule also contained high amounts (10(5)-10(7) cfu/g), of endospore-forming bacteria and Streptomyces-like bacteria. Bacteria from the capsule produced toxic substances when cultured in the laboratory. Three different toxic responses were provoked in the spermatozoa exposed to extracts from the Streptomyces-like isolates: a) hyperpolarisation of the plasma membrane and depolarisation of the mitochondria; b) depolarisation of mitochondria similar to that caused by the capsule content extract; and c) motility inhibition, with no observed change of any cytosolic transmembrane potential. Membrane potential changes in the sperm cells exposed to the bacterial extracts were similar to those provoked by exposure to valinomycin and bafilomycin A1, to nigericin, and to oligomycin and ionomycin, respectively. Extracts prepared from Bacillus isolated from the capsule non-specifically depolarised all the cellular transmembrane potentials. The results demonstrate the potential value of a cell toxicity assay with boar spermatozoa for detecting hazardous substances in products intended for human consumption, without whole-animal exposure or using fetal calf serum for cell cultures.
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Affiliation(s)
- Douwe Hoornstra
- Department of Applied Chemistry and Microbiology, University of Helsinki, Finland
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24
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Nguyen AT, Tallent SM. Screening food for Bacillus cereus toxins using whole genome sequencing. Food Microbiol 2019; 78:164-170. [DOI: 10.1016/j.fm.2018.10.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 08/24/2018] [Accepted: 10/21/2018] [Indexed: 11/24/2022]
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25
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Haddad N, Johnson N, Kathariou S, Métris A, Phister T, Pielaat A, Tassou C, Wells-Bennik MH, Zwietering MH. Next generation microbiological risk assessment—Potential of omics data for hazard characterisation. Int J Food Microbiol 2018; 287:28-39. [DOI: 10.1016/j.ijfoodmicro.2018.04.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 03/31/2018] [Accepted: 04/10/2018] [Indexed: 12/18/2022]
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26
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Bauer T, Sipos W, Stark TD, Käser T, Knecht C, Brunthaler R, Saalmüller A, Hofmann T, Ehling-Schulz M. First Insights Into Within Host Translocation of the Bacillus cereus Toxin Cereulide Using a Porcine Model. Front Microbiol 2018; 9:2652. [PMID: 30464760 PMCID: PMC6234764 DOI: 10.3389/fmicb.2018.02652] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 10/17/2018] [Indexed: 11/13/2022] Open
Abstract
Bacillus cereus is a gram-positive pathogen mainly known to evoke two types of foodborne poisonings. The diarrheal syndrome is caused by enterotoxins produced during growth in the intestine. In contrast, the emetic type is caused by the dodecadepsipeptide cereulide pre-formed in food. Usually, both diseases are self-limiting but occasionally more severe forms, including fatal ones, are reported. Since the mechanisms of cereulide toxin uptake and translocation within the body as well as the mechanism of its toxic action are still unknown, we used a porcine model to investigate the uptake, routes of excretion and distribution of cereulide within the host. Pigs were orally challenged with cereulide using single doses of 10-150 μg cereulide kg-1 body weight to study acute effects or using daily doses of 10 μg cereulide kg-1 body weight administered for 7 days to investigate effects of longtime, chronic exposure. Our study showed that part of cereulide ingested with food is rapidly excreted with feces while part of the cereulide toxin is absorbed, passes through membranes and is distributed within the body. Results from the chronic trial indicate bioaccumulation of cereulide in certain tissues and organs, such as kidney, liver, muscles and fat tissues. Beside its detection in various tissues and organs, our study also demonstrated that cereulide is able to cross the blood-brain-barrier, which may partially explain the cerebral effects reported from human intoxication cases. The neurobehavioral symptoms, such as seizures and lethargy, observed in our porcine model resemble those reported from human food borne intoxications. The rapid onset of these symptoms indicates direct effects of cereulide on the central nervous system (CNS), which warrant further research. The porcine model presented here might be useful to study the specific neurobiological effect in detail. Furthermore, our study revealed that typical diagnostic specimens used in human medicine, such as blood samples and urine, are not suitable for diagnostics of food borne cereulide intoxications. Instead, screening of fecal samples by SIDA-LC-MS may represent a simple and non-invasive method for detection of cereulide intoxications in clinical settings as well as in foodborne outbreak situations.
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Affiliation(s)
- Tobias Bauer
- Department of Pathobiology, Functional Microbiology, Institute of Microbiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Wolfgang Sipos
- University Clinic for Swine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Timo D Stark
- Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München, Freising, Germany
| | - Tobias Käser
- Department of Pathobiology, Institute of Immunology, University of Veterinary Medicine Vienna, Vienna, Austria.,Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University (NCSU), Raleigh, NC, United States
| | - Christian Knecht
- University Clinic for Swine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Rene Brunthaler
- Department of Pathobiology, Institute of Pathology and Forensic Veterinary Medicine, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Armin Saalmüller
- Department of Pathobiology, Institute of Immunology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Thomas Hofmann
- Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München, Freising, Germany
| | - Monika Ehling-Schulz
- Department of Pathobiology, Functional Microbiology, Institute of Microbiology, University of Veterinary Medicine Vienna, Vienna, Austria
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27
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Makarasen A, Reukngam N, Khlaychan P, Chuysinuan P, Isobe M, Techasakul S. Mode of action and synergistic effect of valinomycin and cereulide with amphotericin B against Candida albicans and Cryptococcus albidus. J Mycol Med 2017; 28:112-121. [PMID: 29276078 DOI: 10.1016/j.mycmed.2017.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 11/22/2017] [Accepted: 11/29/2017] [Indexed: 11/16/2022]
Abstract
Both valinomycin and cereulide are cyclic depsipeptides and are known K+ ion-selective ionophores. Valinomycin and cereulide feature low minimum inhibitory concentration (MIC) values against Candida albicans and Cryptococcus albidus. This study aims at investigating the mode of action and verifying the efficacy of valinomycin or cereulide alone and in combination with amphotericin B (AmB) in vitro against both microorganisms. Based on the results from membrane permeability and fluidity assays for detection of plasma membrane permeabilization and membrane dynamics, the present study demonstrated that valinomycin and cereulide exhibit antifungal activity against C. albicans and C. albidus by interrupting membrane-associated function. The mode of action of both valinomycin and cereulide are similar with that of AmB. Time-kill kinetics assay showed that valinomycin and cereulide exhibit fungistatic activity, whereas AmB features fungicidal activity. Additionally, the combination of compounds between each cyclic peptide and AmB reached maximal fungicidal activity more rapidly than AmB alone. This result corresponded with findings of scanning electron microscopy, fractional inhibitory concentration index and minimum fungicidal concentration (MFC)/MIC ratio, indicating that combinations of the drugs show synergistic effects for inhibiting the growth of these fungal strains. Sorbitol and ergosterol assays showed that both cyclic peptides affected cell wall and membrane components due to increases in MIC value, as observed in medium with sorbitol and ergosterol. Valinomycin and cereulide may promote permeability of fungal cell wall and cell membrane when used in combination with AmB.
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Affiliation(s)
- A Makarasen
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand
| | - N Reukngam
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand
| | - P Khlaychan
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand
| | - P Chuysinuan
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand
| | - M Isobe
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand
| | - S Techasakul
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand.
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Guérin A, Rønning HT, Dargaignaratz C, Clavel T, Broussolle V, Mahillon J, Granum PE, Nguyen-The C. Cereulide production by Bacillus weihenstephanensis strains during growth at different pH values and temperatures. Food Microbiol 2017; 65:130-135. [DOI: 10.1016/j.fm.2017.02.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 02/13/2017] [Accepted: 02/15/2017] [Indexed: 11/15/2022]
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Yang Y, Gu H, Yu X, Zhan L, Chen J, Luo Y, Zhang Y, Zhang Y, Lu Y, Jiang J, Mei L. Genotypic heterogeneity of emetic toxin producing Bacillus cereus isolates from China. FEMS Microbiol Lett 2016; 364:fnw237. [PMID: 27744366 DOI: 10.1093/femsle/fnw237] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 06/24/2016] [Accepted: 10/14/2016] [Indexed: 11/14/2022] Open
Abstract
Emetic toxin-producing Bacillus cereus (emetic B. cereus) is the third member of B. cereus group whose toxins are encoded by megaplasmids, beside anthrax and insecticidal toxins of B. anthracis and B. thuringiensis, respectively. A total of 18 emetic isolates collected from food poisoning events, clinical and non-random food samples in Zhejiang province of China, were analyzed by plasmid screening, pulse field gel electrophoresis, multilocus sequence typing, and toxic gene identification to investigate their genotypic diversity. In this study, 13 plasmid profile types, 14 pulse types and 6 different STs from emetic isolates were detected, in which ST 1035,1038,1053,1054 and 1065 were first assigned and reported. The toxic gene ces existed on its own, or coexisted with other toxic genes bceT, cytk, entFM and nhe, but never with hbl in emetic isolates. The results demonstrated that the emetic B. cereus strains from China were heterologous at genotypic level.
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Affiliation(s)
- Yong Yang
- Department of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang Province, China
| | - Hua Gu
- Department of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang Province, China
| | - Xiaofeng Yu
- College of Food Science, Shihezi University, Shihezi 832001, Xinjiang Province, China
| | - Li Zhan
- Department of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang Province, China
| | - Jiancai Chen
- Department of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang Province, China
| | - Yun Luo
- Department of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang Province, China
| | - Yunyi Zhang
- Department of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang Province, China
| | - Yanjun Zhang
- Department of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang Province, China
| | - Yiyu Lu
- Department of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang Province, China
| | - Jianmin Jiang
- Department of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang Province, China
| | - Lingling Mei
- Department of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang Province, China
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Decleer M, Rajkovic A, Sas B, Madder A, De Saeger S. Development and validation of ultra-high-performance liquid chromatography-tandem mass spectrometry methods for the simultaneous determination of beauvericin, enniatins (A, A1, B, B1) and cereulide in maize, wheat, pasta and rice. J Chromatogr A 2016; 1472:35-43. [PMID: 27776774 DOI: 10.1016/j.chroma.2016.10.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/22/2016] [Accepted: 10/04/2016] [Indexed: 01/13/2023]
Abstract
Rapid and accurate UPLC-MS/MS methods for the simultaneous determination of beauvericin and the related enniatins (A, A1, B, B1), together with cereulide were successfully developed and validated in cereal and cereal-based food matrices such as wheat, maize, rice and pasta. Although these emerging foodborne toxins are of different microbial origin, the similar structural, toxicological and food safety features provided rationale for their concurrent detection in relevant food matrices. A Waters Acquity UPLC system coupled to a Waters Quattro Premier XE™ Mass Spectrometer operating in ESI+ mode was employed. Sample pretreatment involved a fast and simple liquid extraction of the target toxins without any further clean-up step. For all toxins the sample preparation resulted in acceptable extraction recoveries with values of 85-105% for wheat, 87-106% for maize, 84-106% for rice and 85-105% for pasta. The efficient extraction protocol, together with a fast chromatographic separation of 7min allowed substantial saving costs and time showing its robustness and performance. The validation of the developed method was performed based on Commission Decision 2002/657/EC. The obtained limits of detection ranged from 0.1 to 1.0μgkg-1 and the limits of quantification from 0.3 to 2.9μgkg-1 for the targeted toxins in the selected matrices. The obtained sensitivities allow detection of relevant toxicological concentrations. All relative standard deviations for repeatability (intra-day) and intermediate precision (inter-day) were lower than 20%. Trueness, expressed as the apparent recovery varied from 80 to 107%. The highly sensitive and repeatable validated method was applied to 57 naturally contaminated samples allowing detection of sub-clinical doses of the toxins.
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Affiliation(s)
- Marlies Decleer
- Department of Bioanalysis, Laboratory of Food Analysis, Ghent University, Ottergemsesteenweg 460, Ghent, Belgium; Department of Food Safety and Food Quality, Laboratory of Food Microbiology and Food Preservation, Ghent University, Coupure Links 653, Ghent, Belgium.
| | - Andreja Rajkovic
- Department of Food Safety and Food Quality, Laboratory of Food Microbiology and Food Preservation, Ghent University, Coupure Links 653, Ghent, Belgium
| | - Benedikt Sas
- Department of Food Safety and Food Quality, Food2Know, Ghent University, Coupure Links 653, Ghent, Belgium
| | - Annemieke Madder
- Department of Organic Chemistry, Organic and Biomimetic Chemistry Research Group, Ghent University, Krijgslaan 281, Ghent, Belgium
| | - Sarah De Saeger
- Department of Bioanalysis, Laboratory of Food Analysis, Ghent University, Ottergemsesteenweg 460, Ghent, Belgium
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31
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Gopal N, Hill C, Ross PR, Beresford TP, Fenelon MA, Cotter PD. The Prevalence and Control of Bacillus and Related Spore-Forming Bacteria in the Dairy Industry. Front Microbiol 2015; 6:1418. [PMID: 26733963 PMCID: PMC4685140 DOI: 10.3389/fmicb.2015.01418] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/30/2015] [Indexed: 01/14/2023] Open
Abstract
Milk produced in udder cells is sterile but due to its high nutrient content, it can be a good growth substrate for contaminating bacteria. The quality of milk is monitored via somatic cell counts and total bacterial counts, with prescribed regulatory limits to ensure quality and safety. Bacterial contaminants can cause disease, or spoilage of milk and its secondary products. Aerobic spore-forming bacteria, such as those from the genera Sporosarcina, Paenisporosarcina, Brevibacillus, Paenibacillus, Geobacillus and Bacillus, are a particular concern in this regard as they are able to survive industrial pasteurization and form biofilms within pipes and stainless steel equipment. These single or multiple-species biofilms become a reservoir of spoilage microorganisms and a cycle of contamination can be initiated. Indeed, previous studies have highlighted that these microorganisms are highly prevalent in dead ends, corners, cracks, crevices, gaskets, valves and the joints of stainless steel equipment used in the dairy manufacturing plants. Hence, adequate monitoring and control measures are essential to prevent spoilage and ensure consumer safety. Common controlling approaches include specific cleaning-in-place processes, chemical and biological biocides and other novel methods. In this review, we highlight the problems caused by these microorganisms, and discuss issues relating to their prevalence, monitoring thereof and control with respect to the dairy industry.
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Affiliation(s)
- Nidhi Gopal
- Teagasc Food Research CentreCork, Ireland
- School of Microbiology, University College CorkCork, Ireland
| | - Colin Hill
- School of Microbiology, University College CorkCork, Ireland
- APC Microbiome InstituteCork, Ireland
| | - Paul R. Ross
- College of Science, Engineering and Food Science, University College CorkCork, Ireland
| | | | | | - Paul D. Cotter
- Teagasc Food Research CentreCork, Ireland
- APC Microbiome InstituteCork, Ireland
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32
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Rønning HT, Madslien EH, Asp TN, Granum PE. Identification and quantification of lichenysin - a possible source of food poisoning. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2015; 32:2120-30. [PMID: 26414385 DOI: 10.1080/19440049.2015.1096967] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Lichenysin produced by 53 different Bacillus licheniformis strains has been structurally examined with a qualitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using quadrupole-time-of-flight mass spectrometry. The same lichenysin isoforms are produced from all strains, indicating that the growth conditions have a stronger influence on the lipopeptide production than the genotype. A rapid method for the quantification of lichenysin from bacterial cell cultures with LC-MS/MS after a simple methanol extraction has been refined. For the first time commercially available lichenysin has been used as calibrant, making quantification more accurate. The trueness for C15-lichenysin has been improved to 94% using matrix-matched calibration with lichenysin compared with 30% using solvent calibration with surfactin. The quantitative method was fully validated based on Commission Decision 2002/657/EC. The LOD of the method was below 1 µg g(-1) and the repeatability ranged from 10% to 16%.
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Affiliation(s)
| | - Elisabeth Henie Madslien
- b Forsvarets forskningsinstitutt FFI , Norwegian Defence Research Establishment , Kjeller , Norway
| | - Tone Normann Asp
- a School of Veterinary Science , Norwegian University of Life Sciences , Oslo , Norway
| | - Per Einar Granum
- a School of Veterinary Science , Norwegian University of Life Sciences , Oslo , Norway
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33
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Marxen S, Stark TD, Rütschle A, Lücking G, Frenzel E, Scherer S, Ehling-Schulz M, Hofmann T. Multiparametric Quantitation of the Bacillus cereus Toxins Cereulide and Isocereulides A-G in Foods. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:8307-8313. [PMID: 26352912 DOI: 10.1021/acs.jafc.5b03705] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Consumption of food products contaminated with cereulide (1), a toxin produced by Bacillus cereus, might cause intoxications with symptoms reported to range from indigestion pain and emesis to death. Recently, a series of structural variants, coined isocereulides A-G (2-8), were identified for the first time to be produced along with cereulide (1). The observation that isocereulide A (2) shows an ∼ 8-fold increased cytotoxicity when compared to 1 urges the development of analytical tools enabling an accurate quantitation of these toxins. Therefore, a rapid, sensitive, and robust stable isotope dilution assay (SIDA) was developed for the combined quantitation of 1-8 by means of UPLC-MS/MS. On average, trueness and precision of the method were 112.5 ± 1.8% RSD, repeatability and reproducibility were 2 and 4% for cereulide and isocereulides A-G, and the LOD and LOQ of 0.1 and 0.5 ng/g, respectively, demonstrated a high sensitivity for the developed SIDA method. Application of this method to food samples revealed elevated levels of 1-8 in two suspicious noodle samples, for example, ranging from 0.59 (7) to 189.08 ng/g (1) in sample 1 and from 5.77 (7) to 6198.17 ng/g (1) in sample 2, whereas the analysis of 25 randomly selected food samples, which have not been the subject to any complaints, did not contain detectable amounts of any of these toxins. As a consequence, this SIDA method could add an important contribution to the knowledge-based risk assessment of B. cereus toxins in foods.
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Affiliation(s)
| | | | | | | | - Elrike Frenzel
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna , 1210 Vienna, Austria
| | - Siegfried Scherer
- Chair of Microbial Ecology, Department of Biosciences, WZW, Technische Universität München , 85350 Freising, Germany
| | - Monika Ehling-Schulz
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna , 1210 Vienna, Austria
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34
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Bamnia M, Kaul G. Cereulide and diarrheal toxin contamination in milk and milk products: a systematic review. TOXIN REV 2015. [DOI: 10.3109/15569543.2015.1063070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Vangoitsenhoven R, Maris M, Overbergh L, Van Loco J, Mathieu C, Van der Schueren B. Cereulide food toxin, beta cell function and diabetes: Facts and hypotheses. Diabetes Res Clin Pract 2015; 109:1-5. [PMID: 25998918 DOI: 10.1016/j.diabres.2015.04.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 04/28/2015] [Indexed: 01/11/2023]
Abstract
The incidence of both type 1 and type 2 diabetes is increasing and although environmental pollutants are believed to be potential culprits, the extent to which they can be held responsible remains uncertain. Some bacterial strains of the Bacillus cereus produce a toxin, cereulide, which is frequently found in starchy meals and which is difficult to eradicate from the food chain as it is highly resistant to heat, acidity and proteolysis. While cereulide is well known to cause acute emetic toxicity when ingested at high doses, several in vitro studies have shown that also extremely low doses of cereulide can be toxic, with beta cells being particularly sensitive. Mechanistically, such low doses impair the mitochondrial activity of the beta cells thereby leading to hampered insulin secretion and cell death, both key traits in the pathophysiology of diabetes. In vivo studies of chronic or repeated low dose exposure to cereulide are currently lacking, but should be performed to further clarify the true relevance of cereulide as a potential environmental contributor to the ongoing diabetes epidemic.
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Affiliation(s)
| | - Michael Maris
- Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium
| | - Lut Overbergh
- Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium
| | - Joris Van Loco
- Scientific Institute of Public Health, Brussels, Belgium
| | - Chantal Mathieu
- Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium
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36
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Castiaux V, Liu X, Delbrassinne L, Mahillon J. Is Cytotoxin K from Bacillus cereus a bona fide enterotoxin? Int J Food Microbiol 2015; 211:79-85. [PMID: 26186121 DOI: 10.1016/j.ijfoodmicro.2015.06.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 06/20/2015] [Accepted: 06/22/2015] [Indexed: 11/19/2022]
Abstract
Cytotoxin K (CytK) produced by Bacillus cereus s.l. has generally been considered to be associated with the foodborne diarrhoeal syndrome. Two distinct variants of CytK have been reported: CytK-1 from Bacillus cytotoxicus and CytK-2 from B. cereus. In order to determine whether CytK plays a significant role in the diarrhoeal disease, the occurrence of cytK genes was assessed among 390 B. cereus isolates with different origins including clinical and food poisoning samples and was found to be 46%. Interestingly, the cytK occurrence was slightly lower in food poisoning and clinical isolates than in environmental samples. Seventy cytK-2 positive strains (including 28 isolates from foodborne outbreaks) were then selected in order to assess their genetic diversity. A genetic dendrogram based on the cytK-2 sequences of these 70 strains and on two cytK-1 sequences from strains NVH 391-98 and 883-00 showed an important diversity. However, no strain clustering according to the origin or source of isolation was observed. These observations were confirmed by Multi-Locus Sequences Typing (MLST) based on five different loci of housekeeping genes (ccpA, recF, sucC, purF and gdpD) for which no grouping of foodborne outbreak strains could be identified. Therefore, the choice of cytK as virulence factor for the diarrhoeal pathotype does not seem to be relevant per se, even though the involvement of CytK in the diarrhoeal syndrome cannot be fully excluded. Potential synergistic effects between CytK and other virulence factors, together with their potential variable expression levels should be further investigated.
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Affiliation(s)
- Virginie Castiaux
- Laboratory of Food and Environmental Microbiology, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Xiaojin Liu
- Laboratory of Food and Environmental Microbiology, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Laurence Delbrassinne
- Laboratory of Food and Environmental Microbiology, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium; Scientific Institute of Public Health, Juliette Wytsman street 14, B-1050 Brussels, Belgium
| | - Jacques Mahillon
- Laboratory of Food and Environmental Microbiology, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
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Alonzo DA, Magarvey NA, Schmeing TM. Characterization of cereulide synthetase, a toxin-producing macromolecular machine. PLoS One 2015; 10:e0128569. [PMID: 26042597 PMCID: PMC4455996 DOI: 10.1371/journal.pone.0128569] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/28/2015] [Indexed: 01/14/2023] Open
Abstract
Cereulide synthetase is a two-protein nonribosomal peptide synthetase system that produces a potent emetic toxin in virulent strains of Bacillus cereus. The toxin cereulide is a depsipeptide, as it consists of alternating aminoacyl and hydroxyacyl residues. The hydroxyacyl residues are derived from keto acid substrates, which cereulide synthetase selects and stereospecifically reduces with imbedded ketoreductase domains before incorporating them into the growing depsipeptide chain. We present an in vitro biochemical characterization of cereulide synthetase. We investigate the kinetics and side chain specificity of α-keto acid selection, evaluate the requirement of an MbtH-like protein for adenylation domain activity, assay the effectiveness of vinylsulfonamide inhibitors on ester-adding modules, perform NADPH turnover experiments and evaluate in vitro depsipeptide biosynthesis. This work also provides biochemical insight into depsipeptide-synthesizing nonribosomal peptide synthetases responsible for other bioactive molecules such as valinomycin, antimycin and kutzneride.
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Affiliation(s)
- Diego A. Alonzo
- Department of Biochemistry, McGill University, Montréal, QC H3G 0B1, Canada
| | - Nathan A. Magarvey
- Department of Chemistry & Chemical Biology, McMaster University, M.G. DeGroote Institute for Infectious Disease Research, 1200 Main St. W, Hamilton, Ontario L8N 3Z5, Canada
| | - T. Martin Schmeing
- Department of Biochemistry, McGill University, Montréal, QC H3G 0B1, Canada
- Groupe de Recherche Axé sur la Structure des Protéines (GRASP), McGill University, Montréal, QC H3G 0B1, Canada
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38
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Rønning HT, Asp TN, Granum PE. Determination and quantification of the emetic toxin cereulide fromBacillus cereusin pasta, rice and cream with liquid chromatography–tandem mass spectrometry. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2015; 32:911-21. [DOI: 10.1080/19440049.2015.1022886] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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39
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The peptide toxin amylosin of Bacillus amyloliquefaciens from moisture-damaged buildings is immunotoxic, induces potassium efflux from mammalian cells, and has antimicrobial activity. Appl Environ Microbiol 2015; 81:2939-49. [PMID: 25681192 DOI: 10.1128/aem.03430-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Amylosin, a heat-stable channel-forming non-ribosomally synthesized peptide toxin produced by strains of Bacillus amyloliquefaciens isolated from moisture-damaged buildings, is shown in this paper to have immunotoxic and cytotoxic effects on human cells as well as antagonistic effects on microbes. Human macrophages exposed to 50 ng of amylosin ml(-1) secreted high levels of cytokines interleukin-1β (IL-1β) and IL-18 within 2 h, indicating activation of the NLRP3 inflammasome, an integral part of the innate immune system. At the same exposure level, expression of IL-1β and IL-18 mRNA increased. Amylosin caused dose-dependent potassium ion efflux from all tested mammalian cells (human monocytes and keratinocytes and porcine sperm cells) at 1 to 2 μM exposure. Amylosin also inhibited the motility of porcine sperm cells and depolarized the mitochondria of human keratinocytes. Amylosin may thus trigger the activation of the NLRP3 inflammasome and subsequently cytokine release by causing potassium efflux from exposed cells. The results of this study indicate that exposure to amylosin activates the innate immune system, which could offer an explanation for the inflammatory symptoms experienced by occupants of moisture-damaged buildings. In addition, the amylosin-producing B. amyloliquefaciens inhibited the growth of both prokaryotic and eukaryotic indoor microbes, and purified amylosin also had an antimicrobial effect. These antimicrobial effects could make amylosin producers dominant and therefore significant causal agents of health problems in some moisture-damaged sites.
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40
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Marxen S, Stark TD, Frenzel E, Rütschle A, Lücking G, Pürstinger G, Pohl EE, Scherer S, Ehling-Schulz M, Hofmann T. Chemodiversity of cereulide, the emetic toxin of Bacillus cereus. Anal Bioanal Chem 2015; 407:2439-53. [PMID: 25665710 DOI: 10.1007/s00216-015-8511-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/17/2015] [Accepted: 01/22/2015] [Indexed: 02/04/2023]
Abstract
Food-borne intoxications are increasingly caused by the dodecadepsipeptide cereulide, the emetic toxin produced by Bacillus cereus. As such intoxications pose a health risk to humans, a more detailed understanding on the chemodiversity of this toxin is mandatory for the reliable risk assessment of B. cereus toxins in foods. Mass spectrometric screening now shows a series of at least 18 cereulide variants, among which the previously unknown isocereulides A-G were determined for the first time by means of UPLC-TOF MS and ion-trap MS(n) sequencing, (13)C-labeling experiments, and post-hydrolytic dipeptide and enantioselective amino acid analysis. The data demonstrate a high microheterogeneity in cereulide and show evidence for a relaxed proof reading function of the non-ribosomal cereulide peptide synthetase complex giving rise to an enhanced cereulide chemodiversity. Most intriguingly, the isocereulides were found to differ widely in their cell toxicity correlating with their ionophoric properties (e.g., purified isocereulide A showed about 8-fold higher cytotoxicity than purified cereulide in the HEp-2 assay and induced an immediate breakdown of bilayer membranes). These findings provide a substantial contribution to the knowledge-based risk assessment of B. cereus toxins in foods, representing a still unsolved challenge in the field of food intoxications.
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Affiliation(s)
- Sandra Marxen
- Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München, Lise-Meitner-Straße 34, 85354, Freising, Germany
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41
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Vicente-Carrillo A, Edebert I, Garside H, Cotgreave I, Rigler R, Loitto V, Magnusson KE, Rodríguez-Martínez H. Boar spermatozoa successfully predict mitochondrial modes of toxicity: implications for drug toxicity testing and the 3R principles. Toxicol In Vitro 2015; 29:582-91. [PMID: 25624015 DOI: 10.1016/j.tiv.2015.01.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 11/01/2014] [Accepted: 01/08/2015] [Indexed: 02/05/2023]
Abstract
Replacement of animal testing by in vitro methods (3-R principles) requires validation of suitable cell models, preferably obtained non-invasively, defying traditional use of explants. Ejaculated spermatozoa are highly dependent on mitochondrial production and consumption of ATP for their metabolism, including motility display, thus becoming a suitable model for capturing multiple modes of action of drugs and other chemicals acting via mitochondrial disturbance. In this study, a hypothesis was tested that the boar spermatozoon is a suitable cell type for toxicity assessment, providing a protocol for 3R-replacement of animals for research and drug-testing. Boar sperm kinetics was challenged with a wide variety of known frank mito-toxic chemicals with previously shown mitochondrial effects, using a semi-automated motility analyser allied with real-time fluorescent probing of mitochondrial potential (MitoTracker & JC-1). Output of this sperm assay (obtained after 30 min) was compared to cell viability (ATP-content, data obtained after 24-48 h) of a hepatome-cell line (HepG2). Results of compound effects significantly correlated (P<0.01) for all sperm variables and for most variables in (HepG2). Dose-dependent decreases of relative ATP content in HepG2 cells correlated to sperm speed (r=0.559) and proportions of motile (r=0.55) or progressively motile (r=0.53) spermatozoa. The significance of the study relies on the objectivity of computerized testing of sperm motility inhibition which is comparable albeit of faster output than somatic cell culture models. Sperm suspensions, easily and painlessly obtained from breeding boars, are confirmed as suitable biosensors for preclinical toxicology screening and ranking of lead compounds in the drug development processes.
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Affiliation(s)
- A Vicente-Carrillo
- Developmental Biology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - I Edebert
- Karlbergsvägen 83 B, Stockholm, Sweden
| | - H Garside
- Drug Safety and Metabolism, AstraZeneca Research and Development, Alderley Park, Macclesfield, Cheshire East SK10 4TG, United Kingdom
| | - I Cotgreave
- Swedish Toxicology Sciences Research Center (Swetox) and Department of Biochemical Toxicology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden
| | - R Rigler
- Department of Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - V Loitto
- Medical Microbiology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - K E Magnusson
- Medical Microbiology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - H Rodríguez-Martínez
- Developmental Biology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
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42
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Mei X, Xu K, Yang L, Yuan Z, Mahillon J, Hu X. The genetic diversity of cereulide biosynthesis gene cluster indicates a composite transposon Tnces in emetic Bacillus weihenstephanensis. BMC Microbiol 2014; 14:149. [PMID: 24906385 PMCID: PMC4057527 DOI: 10.1186/1471-2180-14-149] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Accepted: 05/30/2014] [Indexed: 11/10/2022] Open
Abstract
Background Cereulide is a cyclic dodecadepsipeptide ionophore, produced via non-ribosomal peptide synthetases (NRPS), which in rare cases can lead to human death. Early studies had shown that emetic toxin formation belongs to a homogeneous group of Bacillus cereus sensu stricto and the genetic determinants of cereulide (a 24-kb gene cluster of cesHPTABCD) are located on a 270-kb plasmid related to the Bacillus anthracis virulence plasmid pXO1. Results The whole genome sequences from seven emetic isolates, including two B. cereus sensu stricto and five Bacillus weihenstephanensis strains, were compared, and their inside and adjacent DNA sequences of the cereulide biosynthesis gene clusters were analyzed. The sequence diversity was observed, which classified the seven emetic isolates into three clades. Different genomic locations of the cereulide biosynthesis gene clusters, plasmid-borne and chromosome-borne, were also found. Potential mobile genetic elements (MGEs) were identified in the flanking sequences of the ces gene cluster in all three types. The most striking observation was the identification of a putative composite transposon, Tnces, consisting of two copies of ISces element (belonging to IS6 family) in opposite orientations flanking the ces gene cluster in emetic B. weihenstephanensis. The mobility of this element was tested by replacing the ces gene cluster by a KmR gene marker and performing mating-out transposition assays in Escherichia coli. The results showed that Tnces::km transposes efficiently (1.04 × 10-3 T/R) and produces 8-bp direct repeat (DR) at the insertion sites. Conclusions Cereulide biosynthesis gene clusters display sequence diversity, different genomic locations and association with MGEs, in which the transposition capacity of a resistant derivative of the composite transposon Tnces in E. coli was demonstrated. Further study is needed to look for appropriate genetic tools to analysis the transposition of Tnces in Bacillus spp. and the dynamics of other MGEs flanking the ces gene clusters.
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Affiliation(s)
| | | | | | | | | | - Xiaomin Hu
- Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
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Castiaux V, N'guessan E, Swiecicka I, Delbrassinne L, Dierick K, Mahillon J. Diversity of pulsed-field gel electrophoresis patterns of cereulide-producing isolates of Bacillus cereus and Bacillus weihenstephanensis. FEMS Microbiol Lett 2014; 353:124-31. [PMID: 24627989 DOI: 10.1111/1574-6968.12423] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/06/2014] [Accepted: 03/07/2014] [Indexed: 12/16/2022] Open
Abstract
Bacillus cereus is an important foodborne pathogen causing diarrhoea, emesis and in, rare cases, lethal poisonings. The emetic syndrome is caused by cereulide, a heat-stable toxin. Originally considered as a rather homogenous group, the emetic strains have since been shown to display some diversity, including the existence of two clusters of mesophilic B. cereus and psychrotolerant B. weihenstephanensis. Using pulsed-field gel electrophoresis (PFGE) analysis, this research aimed to better understand the diversity and spatio-temporal occurrence of emetic strains originating from environmental or food niches vs. those isolated from foodborne cases. The diversity was evaluated using a set of 52 B. cereus and B. weihenstephanensis strains isolated between 2000 and 2011 in ten countries. PFGE analysis could discriminate 17 distinct profiles (pulsotypes). The most striking observations were as follows: (1) more than one emetic pulsotype can be observed in a single outbreak; (2) the number of distinct isolates involved in emetic intoxications is limited, and these potentially clonal strains frequently occurred in successive and independent food poisoning cases; (3) isolates from different countries displayed identical profiles; and (4) the cereulide-producing psychrotolerant B. weihenstephanensis were, so far, only isolated from environmental niches.
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Affiliation(s)
- Virginie Castiaux
- Laboratory of Food and Environmental Microbiology, Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
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Kawamura-Sato K, Hirama Y, Agata N, Ito H, Torii K, Takeno A, Hasegawa T, Shimomura Y, Ohta M. Quantitative Analysis of Cereulide, an Emetic Toxin ofBacillus cereus, by Using Rat Liver Mitochondria. Microbiol Immunol 2013; 49:25-30. [PMID: 15665450 DOI: 10.1111/j.1348-0421.2005.tb03636.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
An emetic toxin cereulide, produced by Bacillus cereus, causes emetic food poisonings, but a method for quantitative measurement of cereulide has not been well established. A current detection method is a bioassay method using the HEp-2 cell vacuolation test, but it was unable to measure an accurate concentration. We established a quantitative assay for cereulide based on its mitochondrial respiratory uncoupling activity. The oxygen consumption in a reaction medium containing rat liver mitochondria was rapid in the presence of cereulide. Thus uncoupling effect of cereulide on mitochondrial respiration was similar to those of uncouplers 2,4-dinitrophenol (DNP), carbonylcyanide m-chlorophenylhydrazone (CCCP), and valinomycin. This method gave constant results over a wide range of cereulide concentrations, ranging from 0.05 to 100 microg/ml. The minimum cereulide concentration to detect uncoupled oxygen consumption was 50 ng/ml and increased dose-dependently to the maximum level. Semi-log relationship between the oxygen consumption rate and the cereulide concentration enables this method to quantify cereulide. The results of this method were highly reproducible as compared with the HEp-2 cell vacuolation test and were in good agreement with those of the HEp-2 cell vacuolation test. The enterotoxin of B. cereus or Staphylococcus aureus did not show any effect on the oxygen consumption, indicating this method is specific for the identification of cereulide as a causative agent of emetic food poisonings.
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Affiliation(s)
- Kumiko Kawamura-Sato
- Department of Medical Technology, Nagoya University Graduate School of Health Science, Nagoya, Aichi, Japan
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Madslien EH, Rønning HT, Lindbäck T, Hassel B, Andersson MA, Granum PE. Lichenysin is produced by most Bacillus licheniformis strains. J Appl Microbiol 2013; 115:1068-80. [PMID: 23844764 DOI: 10.1111/jam.12299] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/01/2013] [Accepted: 07/03/2013] [Indexed: 11/28/2022]
Abstract
AIMS The aim of this study was to elucidate the prevalence of lichenysin production in Bacillus licheniformis and to see whether this feature was restricted to certain genotypes. Secondly, we wanted to see whether cytotoxicity reflected the measured levels of lichenysin. METHODS AND RESULTS Fifty-three genotyped strains of B. licheniformis, representing a wide variety of sources, were included. lchAA gene fragments were detected in all strains by polymerase chain reaction (PCR). All 53 strains produced lichenysins with four molecular masses as confirmed by LC-MS/MS (liquid chromatography-tandem mass spectrometry) analysis. The amounts of lichenysin varied more than two orders of magnitude between strains and were irrespective of genotype. Finally, there was a strong association between lichenysin concentrations and toxicity towards boar spermatozoa, erythrocytes and Vero cells. CONCLUSIONS Lichenysin synthesis was universal among the 53 B. licheniformis strains examined. The quantities varied considerably between strains, but were not specifically associated with genotype. Cytotoxicity was evident at lichenysin concentrations above 10 μg ml(-1) , which is in accordance with previous studies. SIGNIFICANCE AND IMPACT OF STUDY This study might be of interest to those working on B. licheniformis for commercial use as well as for authorities who make risk assessments of B. licheniformis when used as a food and feed additive.
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Affiliation(s)
- E H Madslien
- Forsvarets Forskningsinstitutt FFI, Norwegian Defence Research Establishment, Kjeller, Norway; Department of Food Safety and Infection Biology, Section for Food Safety, Norwegian School of Veterinary Science, Oslo, Norway
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Markland SM, Farkas DF, Kniel KE, Hoover DG. Pathogenic psychrotolerant sporeformers: an emerging challenge for low-temperature storage of minimally processed foods. Foodborne Pathog Dis 2013; 10:413-9. [PMID: 23536982 DOI: 10.1089/fpd.2012.1355] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sporeforming bacteria are a significant problem in the food industry as they are ubiquitous in nature and capable of resisting inactivation by heat and chemical treatments designed to inactivate them. Beyond spoilage issues, psychrotolerant sporeformers are becoming increasingly recognized as a potential hazard given the ever-expanding demand for refrigerated processed foods with extended shelf-life. In these products, the sporeforming pathogens of concern are Bacillus cereus, Bacillus weihenstephanensis, and Clostridium botulinum type E. This review article examines the foods, conditions, and organisms responsible for the food safety issue caused by the germination and outgrowth of psychrotolerant sporeforming pathogens in minimally processed refrigerated foods.
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Affiliation(s)
- Sarah M Markland
- Department of Animal and Food Sciences, University of Delaware, Newark, Delaware 19716, USA
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Potato crop as a source of emetic Bacillus cereus and cereulide-induced mammalian cell toxicity. Appl Environ Microbiol 2013; 79:3534-43. [PMID: 23524678 DOI: 10.1128/aem.00201-13] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Bacillus cereus, aseptically isolated from potato tubers, were screened for cereulide production and for toxicity on human and other mammalian cells. The cereulide-producing isolates grew slowly, the colonies remained small (~1 mm), tested negative for starch hydrolysis, and varied in productivity from 1 to 100 ng of cereulide mg (wet weight)(-1) (~0.01 to 1 ng per 10(5) CFU). By DNA-fingerprint analysis, the isolates matched B. cereus F5881/94, connected to human food-borne illness, but were distinct from cereulide-producing endophytes of spruce tree (Picea abies). Exposure to cell extracts (1 to 10 μg of bacterial biomass ml(-1)) and to purified cereulide (0.4 to 7 ng ml(-1)) from the potato isolates caused mitochondrial depolarization (loss of ΔΨm) in human peripheral blood mononuclear cells (PBMC) and keratinocytes (HaCaT), porcine spermatozoa and kidney tubular epithelial cells (PK-15), murine fibroblasts (L-929), and pancreatic insulin-producing cells (MIN-6). Cereulide (10 to 20 ng ml(-1)) exposed pancreatic islets (MIN-6) disintegrated into small pyknotic cells, followed by necrotic death. Necrotic death in other test cells was observed only after a 2-log-higher exposure. Exposure to 30 to 60 ng of cereulide ml(-1) induced K(+) translocation in intact, live PBMC, keratinocytes, and sperm cells within seconds of exposure, depleting 2 to 10% of the cellular K(+) stores within 10 min. The ability of cereulide to transfer K(+) ions across biological membranes may benefit the producer bacterium in K(+)-deficient environments such as extracellular spaces inside plant tissue but is a pathogenic trait when in contact with mammalian cells.
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Duarte A, Poderoso C, Cooke M, Soria G, Cornejo Maciel F, Gottifredi V, Podestá EJ. Mitochondrial fusion is essential for steroid biosynthesis. PLoS One 2012; 7:e45829. [PMID: 23029265 PMCID: PMC3448708 DOI: 10.1371/journal.pone.0045829] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 08/23/2012] [Indexed: 11/19/2022] Open
Abstract
Although the contribution of mitochondrial dynamics (a balance in fusion/fission events and changes in mitochondria subcellular distribution) to key biological process has been reported, the contribution of changes in mitochondrial fusion to achieve efficient steroid production has never been explored. The mitochondria are central during steroid synthesis and different enzymes are localized between the mitochondria and the endoplasmic reticulum to produce the final steroid hormone, thus suggesting that mitochondrial fusion might be relevant for this process. In the present study, we showed that the hormonal stimulation triggers mitochondrial fusion into tubular-shaped structures and we demonstrated that mitochondrial fusion does not only correlate-with but also is an essential step of steroid production, being both events depend on PKA activity. We also demonstrated that the hormone-stimulated relocalization of ERK1/2 in the mitochondrion, a critical step during steroidogenesis, depends on mitochondrial fusion. Additionally, we showed that the SHP2 phosphatase, which is required for full steroidogenesis, simultaneously modulates mitochondrial fusion and ERK1/2 localization in the mitochondrion. Strikingly, we found that mitofusin 2 (Mfn2) expression, a central protein for mitochondrial fusion, is upregulated immediately after hormone stimulation. Moreover, Mfn2 knockdown is sufficient to impair steroid biosynthesis. Together, our findings unveil an essential role for mitochondrial fusion during steroidogenesis. These discoveries highlight the importance of organelles’ reorganization in specialized cells, prompting the exploration of the impact that organelle dynamics has on biological processes that include, but are not limited to, steroid synthesis.
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Affiliation(s)
- Alejandra Duarte
- Instituto de Investigaciones Biomédicas (INBIOMED), Department of Human Biochemistry, School of Medicine, University of Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Cecilia Poderoso
- Instituto de Investigaciones Biomédicas (INBIOMED), Department of Human Biochemistry, School of Medicine, University of Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Mariana Cooke
- Instituto de Investigaciones Biomédicas (INBIOMED), Department of Human Biochemistry, School of Medicine, University of Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Gastón Soria
- Fundación Instituto Leloir-CONICET, University of Buenos Aires, Buenos Aires, Argentina
| | - Fabiana Cornejo Maciel
- Instituto de Investigaciones Biomédicas (INBIOMED), Department of Human Biochemistry, School of Medicine, University of Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Vanesa Gottifredi
- Fundación Instituto Leloir-CONICET, University of Buenos Aires, Buenos Aires, Argentina
| | - Ernesto J. Podestá
- Instituto de Investigaciones Biomédicas (INBIOMED), Department of Human Biochemistry, School of Medicine, University of Buenos Aires-CONICET, Buenos Aires, Argentina
- * E-mail:
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Frenzel E, Doll V, Pauthner M, Lücking G, Scherer S, Ehling-Schulz M. CodY orchestrates the expression of virulence determinants in emetic Bacillus cereus by impacting key regulatory circuits. Mol Microbiol 2012; 85:67-88. [PMID: 22571587 DOI: 10.1111/j.1365-2958.2012.08090.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Bacillus cereus causes gastrointestinal diseases and local and systemic infections elicited by the depsipeptide cereulide, enterotoxins, phospholipases, cytolysins and proteases. The PlcR-PapR quorum sensing system activates the expression of several virulence factors, whereas the Spo0A-AbrB regulatory circuit partially controls the plasmid-borne cereulide synthetase (ces) operon. Here, we show that CodY, a nutrient-responsive regulator of Gram-positive bacteria, has a profound effect on both regulatory systems, which have been assumed to operate independently of each other. Deletion of codY resulted in downregulation of virulence genes belonging to the PlcR regulon and a concomitant upregulation of the ces genes. CodY was found to be a repressor of the ces operon, but did not interact with the promoter regions of PlcR-dependent virulence genes in vitro, suggesting an indirect regulation of the latter. Furthermore, CodY binds to the promoter of the immune inhibitor metalloprotease InhA1, demonstrating that CodY directly links B. cereus metabolism to virulence. In vivo studies using a Galleria mellonella infection model, showed that the codY mutant was substantially attenuated, highlighting the importance of CodY as a key regulator of pathogenicity. Our results demonstrate that CodY profoundly modulates the virulence of B. cereus, possibly controlling the development of pathogenic traits in suitable host environments.
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Affiliation(s)
- Elrike Frenzel
- Institute of Functional Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
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Jiang JH, Tong J, Gabriel K. Hijacking Mitochondria: Bacterial Toxins that Modulate Mitochondrial Function. IUBMB Life 2012; 64:397-401. [DOI: 10.1002/iub.1021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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