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Dos Santos Mascarenhas LR, Vivoni AM, Caetano RG, Rusak LA, Alvarenga VO, Lacerda ICA. Molecular characterization and toxigenic profiles of Bacillus cereus isolates from foodstuff and food poisoning outbreaks in Brazil. Braz J Microbiol 2024; 55:1693-1701. [PMID: 38446406 PMCID: PMC11153380 DOI: 10.1007/s42770-024-01283-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 02/07/2024] [Indexed: 03/07/2024] Open
Abstract
Bacillus cereus sensu stricto (s.s.) is a well-known foodborne pathogen that produces a range of enterotoxins and is able to cause two different types of foodborne illnesses-the emetic and the diarrheal syndromes. In this study, 54 B. cereus s.s. strains isolated from foodstuff and foods involved in food poisoning outbreaks were characterized according to the presence of toxin-encoding genes, virulence-encoding genes, and panC typing. Most isolates were assigned to panC groups IV (61.1%) and III (25.9%), but members of groups II and V could also be found. Investigation of specific alleles revealed high numbers of isolates carrying toxin and other virulence genes including nheA (100%), nheB (100%), hblA (79.6%), hblC (79.6%), hblD (74.1%), cytK-2 (61.1%), clo (100%), pc-plc (75.9%), sph (68.5%), pi-plc (66.6%), hlyIII (62.9%), and hlyII (24.1%). All isolates were negative for ces and cytK-1. In summary, we detected various enterotoxin and other virulence factor genes associated with diarrheal syndrome in strains analyzed, implicated or not with food poisoning. Furthermore, the most isolates analyzed belong to high-risk phylogenetic groups' panC types III and IV. Our study provides a convenient molecular scheme for characterization of B. cereus s.s. strains responsible for food poisoning outbreaks in order to improve the monitoring and investigation and assess emerging clusters and diversity of strains.
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Affiliation(s)
- Luís Renato Dos Santos Mascarenhas
- Food Microbiology Laboratory, Ezequiel Dias Foundation, Belo Horizonte/MG, Brazil.
- Department of Food, Faculty of Pharmacy, Federal University of Minas Gerais, Belo Horizonte/MG, Brazil.
| | | | - Renata Gomes Caetano
- Department of Food, Faculty of Pharmacy, Federal University of Minas Gerais, Belo Horizonte/MG, Brazil
| | - Leonardo Alves Rusak
- Bacterial Physiology Laboratory, Oswaldo Cruz Foundation, Rio de Janeiro/RJ, Brazil
| | - Verônica Ortiz Alvarenga
- Department of Food, Faculty of Pharmacy, Federal University of Minas Gerais, Belo Horizonte/MG, Brazil
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Coburn PS, Miller FC, LaGrow AL, Mursalin H, Gregory A, Parrott A, Astley D, Callegan MC. Virulence-related genotypic differences among Bacillus cereus ocular and gastrointestinal isolates and the relationship to endophthalmitis pathogenesis. Front Cell Infect Microbiol 2023; 13:1304677. [PMID: 38106476 PMCID: PMC10722173 DOI: 10.3389/fcimb.2023.1304677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 11/03/2023] [Indexed: 12/19/2023] Open
Abstract
Background Bacillus cereus (Bc) can cause self-limiting gastrointestinal infections, but when infecting the eye, can cause rapid and irreversible blindness. This study investigated whether clinical ocular and gastrointestinal Bc isolates differed in terms of virulence-related genotypes and endophthalmitis virulence. Methods Twenty-eight Bc ocular, gastrointestinal, and laboratory reference isolates were evaluated. Hemolysis assays were performed to assess potential differences in hemolytic activity. The presence of twenty Bc virulence-related genes was assessed by PCR. A subset of ocular and gastrointestinal isolates differing in PCR positivity for 5 virulence genes was compared to strain ATCC14579 in an experimental murine model of endophthalmitis. At 8 hours post infection, retinal function was evaluated by electroretinography, and intraocular bacterial concentrations were determined by plate counts. Results Gastrointestinal Bc isolates were more hemolytic than the Bc ocular isolates and ATCC14579 (p < 0.0001). Bc ocular isolates were more frequently PCR-positive for capK, cytK, hblA, hblC, and plcR compared to the gastrointestinal isolates (p ≤ 0.0002). In the endophthalmitis model, mean A-wave retention did not differ significantly between eyes infected with ATCC14579 and eyes infected with the selected ocular or gastrointestinal isolates (p ≥ 0.3528). Similar results were observed for mean B-wave retention (p ≥ 0.0640). Only one diarrheal isolate showed significantly greater B-wave retention when compared to ATCC14579 (p = 0.0303). No significant differences in mean A-wave (p ≥ 0.1535) or B-wave (p ≥ 0.0727) retention between the selected ocular and gastrointestinal isolates were observed. Intraocular concentrations of ATCC14579 were significantly higher than the selected ocular isolate and 3 of the gastrointestinal isolates (p ≤ 0.0303). Intraocular concentrations of the selected ocular isolate were not significantly different from the gastrointestinal isolates (p ≥ 0.1923). Conclusions Among the subset of virulence-related genes assessed, 5 were significantly enriched among the ocular isolates compared to gastrointestinal isolates. While hemolytic activity was higher among gastrointestinal isolates, retinal function retention and intraocular growth was not significantly different between the selected ocular and gastrointestinal isolates. These results suggest that Bc strains causing gastrointestinal infections, while differing from ocular isolates in hemolytic activity and virulence-related gene profile, are similarly virulent in endophthalmitis.
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Affiliation(s)
- Phillip S. Coburn
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Frederick C. Miller
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Department of Family and Preventive Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Austin L. LaGrow
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Huzzatul Mursalin
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Anna Gregory
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Aaron Parrott
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Daniel Astley
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Michelle C. Callegan
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Dean McGee Eye Institute, Oklahoma City, OK, United States
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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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Zhao Y, Su L, Li K, Zhao B. Discovery of novel PC‐PLC activity inhibitors. Chem Biol Drug Des 2019; 95:380-387. [DOI: 10.1111/cbdd.13606] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 06/13/2019] [Accepted: 08/03/2019] [Indexed: 12/31/2022]
Affiliation(s)
- YanChun Zhao
- Jinan Hangchen Biotechnology Co., Ltd. Jinan China
| | - Le Su
- State Key Laboratory of Biobased Material and Green Papermaking School of Bioengineering Shandong Academy of Sciences Qilu University of Technology Jinan China
| | - Kunlun Li
- Jinan Hangchen Biotechnology Co., Ltd. Jinan China
| | - BaoXiang Zhao
- Institute of Organic Chemistry School of Chemistry and Chemical Engineering Shandong University Jinan China
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Characterization of Enterotoxigenic Bacillus cereus sensu lato and Staphylococcus aureus Isolates and Associated Enterotoxin Production Dynamics in Milk or Meat-Based Broth. Toxins (Basel) 2017; 9:toxins9070225. [PMID: 28714887 PMCID: PMC5535172 DOI: 10.3390/toxins9070225] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/13/2017] [Accepted: 07/13/2017] [Indexed: 02/05/2023] Open
Abstract
Bacillus cereus sensu lato species, as well as Staphylococcus aureus, are important pathogenic bacteria which can cause foodborne illness through the production of enterotoxins. This study characterised enterotoxin genes of these species and examined growth and enterotoxin production dynamics of isolates when grown in milk or meat-based broth. All B. cereus s. l. isolates harboured nheA, hblA and entFM toxin genes, with lower prevalence of bceT and hlyII. When grown at 16 °C, toxin production by individual B. cereus s. l. isolates varied depending on the food matrix; toxin was detected at cell densities below 5 log10(CFU/mL). At 16 °C no staphylococcal enterotoxin C (SEC) production was detected by S. aureus isolates, although low levels of SED production was noted. At 30 °C all S. aureus isolates produced detectable enterotoxin in the simulated meat matrix, whereas SEC production was significantly reduced in milk. Relative to B. cereus s. l. toxin production, S. aureus typically required reaching higher cell numbers to produce detectable levels of enterotoxin. Phylogenetic analysis of the sec and sel genes suggested population evolution which correlated with animal host adaptation, with subgroups of bovine isolates or caprine/ovine isolates noted, which were distinct from human isolates. Taken together, this study highlights the marked differences in the production of enterotoxins both associated with different growth matrices themselves, but also in the behaviour of individual strains when exposed to different food matrices.
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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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Ehling-Schulz M, Frenzel E, Gohar M. Food-bacteria interplay: pathometabolism of emetic Bacillus cereus. Front Microbiol 2015; 6:704. [PMID: 26236290 PMCID: PMC4500953 DOI: 10.3389/fmicb.2015.00704] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 06/26/2015] [Indexed: 11/25/2022] Open
Abstract
Bacillus cereus is a Gram-positive endospore forming bacterium known for its wide spectrum of phenotypic traits, enabling it to occupy diverse ecological niches. Although the population structure of B. cereus is highly dynamic and rather panmictic, production of the emetic B. cereus toxin cereulide is restricted to strains with specific genotypic traits, associated with distinct environmental habitats. Cereulide is an ionophoric dodecadepsipeptide that is produced non-ribosomally by an enzyme complex with an unusual modular structure, named cereulide synthetase (Ces non-ribosomal peptide synthetase). The ces gene locus is encoded on a mega virulence plasmid related to the B. anthracis toxin plasmid pXO1. Cereulide, a highly thermo- and pH- resistant molecule, is preformed in food, evokes vomiting a few hours after ingestion, and was shown to be the direct cause of gastroenteritis symptoms; occasionally it is implicated in severe clinical manifestations including acute liver failures. Control of toxin gene expression in emetic B. cereus involves central transcriptional regulators, such as CodY and AbrB, thereby inextricably linking toxin gene expression to life cycle phases and specific conditions, such as the nutrient supply encountered in food matrices. While in recent years considerable progress has been made in the molecular and biochemical characterization of cereulide toxin synthesis, far less is known about the embedment of toxin synthesis in the life cycle of B. cereus. Information about signals acting on toxin production in the food environment is lacking. We summarize the data available on the complex regulatory network controlling cereulide toxin synthesis, discuss the role of intrinsic and extrinsic factors acting on toxin biosynthesis in emetic B. cereus and stress how unraveling these processes can lead to the development of novel effective strategies to prevent toxin synthesis in the food production and processing chain.
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Affiliation(s)
- Monika Ehling-Schulz
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine ViennaVienna, Austria
| | - Elrike Frenzel
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine ViennaVienna, Austria
| | - Michel Gohar
- INRA, UMR1319 Micalis, AgroParistech – Domaine de Vilvert, Génétique Microbienne et EnvironnementJouy-en-Josas, France
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