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Xiao Z, Cheng M, Hu X, Xue M, Jiang N, Liu W, Fan Y, Meng Y, Xu C, Zhou Y. Pathological changes of highly pathogenic Bacillus cereus on Pelodiscus sinensis. Vet Q 2023; 43:1-10. [PMID: 38010068 PMCID: PMC11003482 DOI: 10.1080/01652176.2023.2287191] [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: 07/27/2023] [Accepted: 11/15/2023] [Indexed: 11/29/2023] Open
Abstract
An outbreak of a disease with a high mortality rate occurred in a Chinese Softshell Turtle (Pelodiscus sinensis) farm in Hubei Province. This study isolated a highly pathogenic Bacillus cereus strain (Y271) from diseased P. sinensis. Y271 has β hemolysis, containing both Hemolysin BL (hblA, hblC, and hblD), Non-hemolytic enterotoxin, NHE (nheA, nheB, and nheC), and Enterotoxin FM (entFM) genes. Y271 is highly pathogenic against P. sinensis with an LD50 = 6.80 × 103 CFU/g weight. B. cereus was detected in multiple tissues of the infected P. sinensis. Among them, spleen tissue showed the highest copy number density (1.54 ± 0.12 × 104 copies/mg). Multiple tissues and organs of diseased P. sinensis exhibited significant pathological damage, especially the spleen, liver, kidney, and intestine. It showed obvious tissue structure destruction, lesions, necrosis, red blood cells, and inflammatory cell infiltration. B. cereus proliferating in the spleen, liver, and other tissues was observed. The intestinal microbiota of the diseased P. sinensis was altered, with a greater abundance of Firmicutes, Fusobacterium, and Actinomyces than in the healthy group. Allobaculum, Rothia, Aeromonas, and Clostridium abundance were higher in the diseased group than in the healthy group. The number of unique microbial taxa (472) in the disease group was lower than that of the healthy group (705). Y271 was sensitive to multiple drugs, including florfenicol, enrofloxacin, neomycin, and doxycycline. B. cereus is the etiological agent responsible for the massive death of P. sinensis and reveals its potential risks during P. sinensis cultivation.
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Affiliation(s)
- Zidong Xiao
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, China
| | - Mengmeng Cheng
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, China
- College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
| | - Xiaowei Hu
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, China
- Department of Fisheries Development, College of Fisheries, Henan Normal University, Xinxiang, China
| | - Mingyang Xue
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, China
| | - Nan Jiang
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, China
| | - Wei Liu
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, China
| | - Yuding Fan
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, China
| | - Yan Meng
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, China
| | - Chen Xu
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, China
| | - Yong Zhou
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, China
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Cheng LW, Byadgi OV, Tsai CE, Wang PC, Chen SC. Pathogenicity and Genomic Characterization of a Novel Genospecies, Bacillus shihchuchen, of the Bacillus cereus Group Isolated from Chinese Softshell Turtle ( Pelodiscus sinensis). Int J Mol Sci 2023; 24:ijms24119636. [PMID: 37298593 DOI: 10.3390/ijms24119636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 05/25/2023] [Accepted: 05/27/2023] [Indexed: 06/12/2023] Open
Abstract
The Chinese softshell turtle (CST; Pelodiscus sinensis) is a freshwater aquaculture species of substantial economic importance that is commercially farmed across Asia, particularly in Taiwan. Although diseases caused by the Bacillus cereus group (Bcg) pose a major threat to commercial CST farming systems, information regarding its pathogenicity and genome remains limited. Here, we investigated the pathogenicity of Bcg strains isolated in a previous study and performed whole-genome sequencing. Pathogenicity analysis indicated that QF108-045 isolated from CSTs caused the highest mortality rate, and whole-genome sequencing revealed that it was an independent group distinct from other known Bcg genospecies. The average nucleotide identity compared to other known Bcg genospecies was below 95%, suggesting that QF108-045 belongs to a new genospecies, which we named Bacillus shihchuchen. Furthermore, genes annotation revealed the presence of anthrax toxins, such as edema factor and protective antigen, in QF108-045. Therefore, the biovar anthracis was assigned, and the full name of QF108-045 was Bacillus shihchuchen biovar anthracis. In addition to possessing multiple drug-resistant genes, QF108-045 demonstrated resistance to various types of antibiotics, including penicillins (amoxicillin and ampicillin), cephalosporins (ceftifour, cephalexin, and cephazolin), and polypeptides, such as vancomycin.
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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 91201, Taiwan
- Southern Taiwan Fish Diseases Research Centre, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
| | - Omkar Vijay Byadgi
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
| | - Chin-En Tsai
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
| | - Pei-Chi Wang
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Southern Taiwan Fish Diseases Research Centre, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Research Centre for Fish Vaccine and Diseases, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
| | - Shih-Chu Chen
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Southern Taiwan Fish Diseases Research Centre, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Research Centre for Fish Vaccine and Diseases, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Research Centre for Animal Biologics, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
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Luo Z, Sun H, Hao S, Ma Y, Zhang Z, Feng S, Bai X. First report of a disease caused by Bacillus cereus in cultured loach Paramisgurnus dabryanus. DISEASES OF AQUATIC ORGANISMS 2021; 147:87-95. [PMID: 34854820 DOI: 10.3354/dao03629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Bacillus cereus is commonly considered a bacterium pathogenic to mammals, but several studies have suggested that it also induces diseases in fish. In 2017 and 2018, 2 strains of B. cereus, NQ-2017-17 and NQ-2018-8, were isolated from diseased large-scale loach Paramisgurnus dabryanus in Tianjin, China, and were considered to be the pathogens responsible for the disease. These stains were identified as B. cereus based on the results of 16S rDNA gene sequence analysis, Vitek biochemical tests, physiological and biochemical tests, and B. cereus group species-specific PCR. Strains NQ-2017-7 and NQ-2018-8 were found to contain virulence genes (e.g. hblA, hblC, hblD, entFM, and bceT) causing pathological damage to the spleen, kidneys, liver, and gills of loach. The median lethal dose (LD50) of NQ-2017-7 and NQ-2018-8 for loach were 1.0 ×106.64 and 1.0 ×106.49 CFU ml-1, respectively. To our knowledge, this is the first report of loach disease caused by a member of the genus Bacillus.
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Affiliation(s)
- Zhang Luo
- Tianjin Fisheries Research Institute, 442 Jiefangnan Road, Tianjin 300221, PR China
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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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