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Cheng LW, Rao S, Poudyal S, Wang PC, Chen SC. Genotype and virulence gene analyses of Bacillus cereus group clinical isolates from the Chinese softshell turtle (Pelodiscus sinensis) in Taiwan. JOURNAL OF FISH DISEASES 2021; 44:1515-1529. [PMID: 34125451 DOI: 10.1111/jfd.13473] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 06/12/2023]
Abstract
Chinese softshell turtles (Pelodiscus sinensis) (CST) are susceptible to infections by bacteria belonging to the Bacillus cereus group (Bcg). Bcg includes several closely related species, two of which, B. cereus and B. thuringiensis, are pathogens of aquatic animals or insects. In the present study, we collected 57 Bcg isolates obtained from diseased CST from 2016 to 2019 in Kaohsiung and Pingtung, the areas with the most CST farms in Taiwan. All isolates were divided into four genotypes with two restriction enzymes, SmaI and NotI, by pulsed-field gel electrophoresis and enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). Representative isolates from each genotype were subjected to phylogenetic tree analysis using 16S rDNA and pyruvate carboxylase genes as phylogenetic markers, and these CST isolates appeared in different clades. PCR was performed targeting six selected virulence genes, four of which were detected in CST isolates, including cytotoxin K (1/57), hblC of the haemolysin BL complex (46/57), nheA of the non-haemolytic enterotoxin complex (52/57) and enterotoxin FM (57/57), whereas cereulide synthetase and cereulide peptide synthase-like genes were not detected in any isolates.
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Affiliation(s)
- Li-Wu Cheng
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- College of Veterinary Medicine, Southern Taiwan Fish Diseases Research Centre, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Shreesha Rao
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Sayuj Poudyal
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Pei-Chi Wang
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- College of Veterinary Medicine, Southern Taiwan Fish Diseases Research Centre, National Pingtung University of Science and Technology, Pingtung, Taiwan
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Research Centre for Fish Vaccine and Diseases, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Shih-Chu Chen
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- College of Veterinary Medicine, Southern Taiwan Fish Diseases Research Centre, National Pingtung University of Science and Technology, Pingtung, Taiwan
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Research Centre for Fish Vaccine and Diseases, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Research Centre for Animal Biologics, National Pingtung University of Science and Technology, Pingtung, Taiwan
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Incidence, toxin gene profiling, antimicrobial susceptibility, and genetic diversity of Bacillus cereus isolated from quick-frozen food in China. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2020.110824] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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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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