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Heckman TI, Yazdi Z, Pomaranski EK, Sebastião FDA, Mukkatira K, Vuglar BM, Cain KD, Loch TP, Soto E. Atypical flavobacteria recovered from diseased fish in the Western United States. Front Cell Infect Microbiol 2023; 13:1149032. [PMID: 37153143 PMCID: PMC10161732 DOI: 10.3389/fcimb.2023.1149032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/07/2023] [Indexed: 05/09/2023] Open
Abstract
Flavobacterial diseases, caused by bacteria in the order Flavobacteriales, are responsible for devastating losses in farmed and wild fish populations worldwide. The genera Flavobacterium (Family Flavobacteriaceae) and Chryseobacterium (Weeksellaceae) encompass the most well-known agents of fish disease in the order, but the full extent of piscine-pathogenic species within these diverse groups is unresolved, and likely underappreciated. To identify emerging agents of flavobacterial disease in US aquaculture, 183 presumptive Flavobacterium and Chryseobacterium isolates were collected from clinically affected fish representing 19 host types, from across six western states. Isolates were characterized by 16S rRNA gene sequencing and phylogenetic analysis using the gyrB gene. Antimicrobial susceptibility profiles were compared between representatives from each major phylogenetic clade. Of the isolates, 52 were identified as Chryseobacterium species and 131 as Flavobacterium. The majority of Chryseobacterium isolates fell into six clades (A-F) consisting of ≥ 5 fish isolates with ≥ 70% bootstrap support, and Flavobacterium into nine (A-I). Phylogenetic clades showed distinct patterns in antimicrobial susceptibility. Two Chryseobacterium clades (F & G), and four Flavobacterium clades (B, G-I) had comparably high minimal inhibitory concentrations (MICs) for 11/18 antimicrobials tested. Multiple clades in both genera exhibited MICs surpassing the established F. psychrophilum breakpoints for oxytetracycline and florfenicol, indicating potential resistance to two of the three antimicrobials approved for use in finfish aquaculture. Further work to investigate the virulence and antigenic diversity of these genetic groups will improve our understanding of flavobacterial disease, with applications for treatment and vaccination strategies.
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Affiliation(s)
- Taylor I. Heckman
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Zeinab Yazdi
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Eric K. Pomaranski
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Fernanda de Alexandre Sebastião
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- Fisheries, Embrapa Amazônia Ocidental, Manaus, Amazonas, Brazil
| | - Kaveramma Mukkatira
- Fish Health Laboratory, California Department of Fish and Wildlife, Rancho Cordova, CA, United States
| | - Brent M. Vuglar
- Department of Fish and Wildlife Sciences, College of Natural Resources, University of Idaho, Moscow, ID, United States
| | - Kenneth D. Cain
- Department of Fish and Wildlife Sciences, College of Natural Resources, University of Idaho, Moscow, ID, United States
| | - Thomas P. Loch
- Department of Fisheries and Wildlife, College of Agriculture and Natural Resources, Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
| | - Esteban Soto
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- *Correspondence: Esteban Soto,
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Huang X, Li M, Wang J, Ji L, Geng Y, Ou Y, Yang S, Yin L, Li L, Chen D. Effect of Bacterial Infection on the Edibility of Aquatic Products: The Case of Crayfish ( Procambarus clarkii) Infected With Citrobacter freundii. Front Microbiol 2021; 12:722037. [PMID: 34659149 PMCID: PMC8511708 DOI: 10.3389/fmicb.2021.722037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 08/31/2021] [Indexed: 11/13/2022] Open
Abstract
Aquatic products are one of the world's essential protein sources whose quality and safety are threatened by bacterial diseases. This study investigated the possible effects of bacterial infection on the main edible part, the muscle, in the case of crayfish infected with Citrobacter freundii. The histopathological analysis confirmed that crayfish was sensitive to C. freundii and muscle was one of the target organs. The transcriptome results showed impaired intercellular junctions, downregulation of actin expression, and inhibition of metabolic pathways. Furthermore, transcriptomic results suggest that C. freundii mainly affect muscle structure and nutrition. Subsequent validation experiments confirmed structural damage and nutrient loss in C. freundii infected crayfish muscle. Besides, the spoilage tests showed that C. freundii did not accelerate muscle spoilage and the bacteria had a limited impact on food safety. Therefore, although C. freundii may not be a specific spoilage bacterium, it still affects the edible taste and nutritional value of crayfish muscle. The findings of this study might contribute to further research on C. freundii infection and provide a warning about the adverse effects of bacterial infection on aquatic products.
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Affiliation(s)
- Xiaoli Huang
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Minghao Li
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Jincheng Wang
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Lili Ji
- Meat Processing Key Laboratory of Sichuan Province, Chengdu University, Chengdu, China
| | - Yi Geng
- Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yangping Ou
- Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Shiyong Yang
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Lizi Yin
- Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Liangyu Li
- Chengdu Academy of Agriculture and Forestry Sciences, Chengdu, China
| | - Defang Chen
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
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Multifactorial Causes of Chronic Mortality in Juvenile Sturgeon ( Huso huso). Animals (Basel) 2020; 10:ani10101866. [PMID: 33066257 PMCID: PMC7602020 DOI: 10.3390/ani10101866] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/08/2020] [Accepted: 10/09/2020] [Indexed: 01/05/2023] Open
Abstract
This investigation focused on an episode of chronic mortality observed in juvenile Huso huso sturgeons. The examined subjects underwent pathological, microbiological, molecular, and chemical investigations. Grossly severe body shape deformities, epaxial muscle softening, and multifocal ulcerative dermatitis were the main observed findings. The more constant histopathologic findings were moderate to severe rarefaction and disorganization of the lymphohematopoietic lymphoid tissues, myofiber degeneration, atrophy and interstitial edema of skeletal epaxial muscles, and degeneration and atrophy of the gangliar neurons close to the myofibers. Chemical investigations showed a lower selenium concentration in affected animals, suggesting nutritional myopathy. Other manifestations were nephrocalcinosis and splenic vessel wall hyalinosis. Septicemia due to bacteria such as Aeromonas veronii, Shewanella putrefaciens, Citrobacter freundii, Chryseobacterium sp., and pigmented hyphae were found. No major sturgeon viral pathogens were detected by classical methods. Next-generation sequencing (NGS) analysis confirmed the absence of viral pathogens, with the exception of herpesvirus, at the order level; also, the presence of Aeromonas veronii and Shewanella putrefaciens was confirmed at the family level by the metagenomic classification of NGS data. In the absence of a primary yet undetected biological cause, it is supposed that environmental stressors, including nutritional imbalances, may have led to immune system impairment, facilitating the entry of opportunistic bacteria and mycotic hyphae.
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