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LaFrentz BR, Khoo LH, Lawrence ML, Petrie-Hanson L, Hanson LA, Baumgartner WA, Hemstreet WG, Kelly AM, García JC, Shelley JP, Johnston AE, Bruce TJ, Griffin MJ. Flavobacterium covae is the predominant species of columnaris-causing bacteria impacting the Channel Catfish industry in the southeastern United States. JOURNAL OF AQUATIC ANIMAL HEALTH 2024; 36:3-15. [PMID: 37859458 DOI: 10.1002/aah.10207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/21/2023]
Abstract
OBJECTIVE Columnaris disease is a leading cause of disease-related losses in the catfish industry of the southeastern United States. The term "columnaris-causing bacteria" (CCB) has been coined in reference to the four described species that cause columnaris disease: Flavobacterium columnare, F. covae, F. davisii, and F. oreochromis. Historically, F. columnare, F. covae, and F. davisii have been isolated from columnaris disease cases in the catfish industry; however, there is a lack of knowledge of which CCB species are most prevalent in farm-raised catfish. The current research objectives were to (1) sample columnaris disease cases from the U.S. catfish industry and identify the species of CCB involved and (2) determine the virulence of the four CCB species in Channel Catfish Ictalurus punctatus in controlled laboratory challenges. METHODS Bacterial isolates or swabs of external lesions from catfish were collected from 259 columnaris disease cases in Mississippi and Alabama during 2015-2019. The DNA extracted from the samples was analyzed using a CCB-specific multiplex polymerase chain reaction to identify the CCB present in each diagnostic case. Channel Catfish were challenged by immersion with isolates belonging to each CCB species to determine virulence at ~28°C and 20°C. RESULT Flavobacterium covae was identified as the predominant CCB species impacting the U.S. catfish industry, as it was present in 94.2% (n = 244) of diagnostic case submissions. Challenge experiments demonstrated that F. covae and F. oreochromis were highly virulent to Channel Catfish, with most isolates resulting in near 100% mortality. In contrast, F. columnare and F. davisii were less virulent, with most isolates resulting in less than 40% mortality. CONCLUSION Collectively, these results demonstrate that F. covae is the predominant CCB in the U.S. catfish industry, and research aimed at developing new control and prevention strategies should target this bacterial species. The methods described herein can be used to continue monitoring the prevalence of CCB in the catfish industry and can be easily applied to other industries to identify which Flavobacterium species have the greatest impact.
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Affiliation(s)
- Benjamin R LaFrentz
- U.S. Department of Agriculture, Agricultural Research Service, Aquatic Animal Health Research Unit, Auburn, Alabama, USA
| | - Lester H Khoo
- Thad Cochran National Warmwater Aquaculture Center, Aquatic Research and Diagnostic Laboratory, Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Stoneville, Mississippi, USA
| | - Mark L Lawrence
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi, USA
| | - Lora Petrie-Hanson
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi, USA
| | - Larry A Hanson
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi, USA
| | - Wes A Baumgartner
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi, USA
| | - William G Hemstreet
- School of Fisheries, Aquaculture, and Aquatic Sciences, College of Agriculture, Auburn University, Auburn, Alabama, USA
| | - Anita M Kelly
- School of Fisheries, Aquaculture, and Aquatic Sciences, College of Agriculture, Auburn University, Auburn, Alabama, USA
| | - Julio C García
- U.S. Department of Agriculture, Agricultural Research Service, Aquatic Animal Health Research Unit, Auburn, Alabama, USA
| | - John P Shelley
- U.S. Department of Agriculture, Agricultural Research Service, Aquatic Animal Health Research Unit, Auburn, Alabama, USA
| | - Amber E Johnston
- U.S. Department of Agriculture, Agricultural Research Service, Aquatic Animal Health Research Unit, Auburn, Alabama, USA
| | - Timothy J Bruce
- School of Fisheries, Aquaculture, and Aquatic Sciences, College of Agriculture, Auburn University, Auburn, Alabama, USA
| | - Matt J Griffin
- Thad Cochran National Warmwater Aquaculture Center, Aquatic Research and Diagnostic Laboratory, Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Stoneville, Mississippi, USA
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Kong W, Yang P, Ding G, Cheng G, Xu Z. Elucidating the dynamic immune responses within the ocular mucosa of rainbow trout ( Oncorhynchus mykiss) after infection with Flavobacterium columnare. Front Immunol 2023; 14:1288223. [PMID: 38077363 PMCID: PMC10702956 DOI: 10.3389/fimmu.2023.1288223] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 10/26/2023] [Indexed: 12/18/2023] Open
Abstract
The eye of vertebrates is constantly faced with numerous challenges from aquatic or airborne pathogens. As a crucial first line of defense, the ocular mucosa (OM) protects the visual organ from external threats in vertebrates such as birds and mammals. However, the understanding of ocular mucosal immunity in early vertebrates, such as teleost fish, remains limited, particularly concerning their resistance to bacterial infections. To gain insights into the pivotal role of the OM in antibacterial immunity among teleost fish, we developed a bacterial infection model using Flavobacterium columnare in rainbow trout (Oncorhynchus mykiss). Here the qPCR and immunofluorescence results showed that F. columnare could invade trout OM, suggesting that the OM could be a primary target and barrier for the bacteria. Moreover, immune-related genes (il-6, il-8, il-11, cxcl10, nod1, il1-b, igm, igt, etc.) were upregulated in the OM of trout following F. columnare infection, as confirmed by qPCR, which was further proved through RNA-seq. The results of transcriptome analyses showed that bacterial infection critically triggers a robust immune response, including innate, and adaptive immune-related signaling pathways such as Toll-like, NOD-like, and C-type lectin receptor signaling pathway and immune network for IgA production, which underscores the immune role of the OM in bacterial infection. Interestingly, a substantial reduction in the expression of genes associated with visual function was observed after infection, indicating that bacterial infection could impact ocular function. Overall, our findings have unveiled a robust mucosal immune response to bacterial infection in the teleost OM for the first time, providing valuable insights for future research into the mechanisms and functions of ocular mucosal immunity in early vertebrate species.
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Affiliation(s)
- Weiguang Kong
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Peng Yang
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Guangyi Ding
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Gaofeng Cheng
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Zhen Xu
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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Han R, Hong Y, Xu R, Guo W, Zhang M, Lu Z, Han Q, Mo Z, Dan X, Li Y. Genomic evidence of genetic diversity and functional evolution in Flavobacterium columnare. Front Microbiol 2023; 14:1240471. [PMID: 37840739 PMCID: PMC10568018 DOI: 10.3389/fmicb.2023.1240471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/06/2023] [Indexed: 10/17/2023] Open
Abstract
Flavobacterium columnare is the causative agent of columnaris disease in freshwater fish. Columnaris disease can cause heavy economic losses in aquaculture. In this study, whole-genome sequencing was used to characterize this pathogen. F. columnare isolate AH-01 had a circular chromosome and plasmid that encoded a total of 3,022 genes. Isolate GX-01 only had a circular chromosome and encoded 2,965 genes. Genomic islands, prophage regions, and CRISPR/Cas systems were identified in both genomes. Both genomes presented evidence of gene variation and horizontal transfer, both of which are the essential components of genetic diversity, genome plasticity, and functional evolution. Single-gene phylogeny and comparative genome analyses were performed to investigate the variation and evolution of this pathogen. Genetic analysis of 16S rRNA and housekeeping gene sequences significantly clustered 55 F. columnare isolates into four clades. The intragroup identity of the 16S rRNA gene exceeded 99%, while the intergroup identity was below the species delineation threshold. We discovered significant translocation, inversion, and rearrangement events that influenced local synteny within each group. Notably, the observed alignments varied considerably among all the studied groups. The core genomes of all strains with available sequences comprised 747 genes, corresponding to approximately 25% of the genome. Core genome multilocus sequence typing, genome-wide orthology and phylogenetic analyses, and average nucleotide identity suggested that the currently existing F. columnare was an assemblage of several distinct species, with levels of divergence at least equivalent to those between recognized bacterial species. The present investigation provided genomic evidence of gene variation and horizontal transfer, which were the basis of genetic diversity, genome plasticity, and functional evolution. The findings supported a proposed new taxonomic perspective on F. columnare.
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Affiliation(s)
- Rui Han
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, China
| | - Yuhao Hong
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Ruilong Xu
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Wenjie Guo
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Mingshu Zhang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, China
| | - Zijun Lu
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Qing Han
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China
| | - Zequan Mo
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, China
| | - Xueming Dan
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, China
| | - Yanwei Li
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, China
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Tuttle JT, Bruce TJ, Butts IAE, Roy LA, Abdelrahman HA, Beck BH, Kelly AM. Investigating the Ability of Edwardsiella ictaluri and Flavobacterium covae to Persist within Commercial Catfish Pond Sediments under Laboratory Conditions. Pathogens 2023; 12:871. [PMID: 37513718 PMCID: PMC10385248 DOI: 10.3390/pathogens12070871] [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: 04/11/2023] [Revised: 05/26/2023] [Accepted: 06/22/2023] [Indexed: 07/30/2023] Open
Abstract
Two prevalent bacterial diseases in catfish aquaculture are enteric septicemia of catfish and columnaris disease caused by Edwardsiella ictaluri and Flavobacterium covae, respectively. Chronic and recurring outbreaks of these bacterial pathogens result in significant economic losses for producers annually. Determining if these pathogens can persist within sediments of commercial ponds is paramount. Experimental persistence trials (PT) were conducted to evaluate the persistence of E. ictaluri and F. covae in pond sediments. Twelve test chambers containing 120 g of sterilized sediment from four commercial catfish ponds were inoculated with either E. ictaluri (S97-773) or F. covae (ALG-00-530) and filled with 8 L of disinfected water. At 1, 2, 4-, 6-, 8-, and 15-days post-inoculation, 1 g of sediment was removed, and colony-forming units (CFU) were enumerated on selective media using 6 × 6 drop plate methods. E. ictaluri population peaked on Day 3 at 6.4 ± 0.5 log10 CFU g-1. Correlation analysis revealed no correlation between the sediment physicochemical parameters and E. ictaluri log10 CFU g-1. However, no viable F. covae colonies were recovered after two PT attempts. Future studies to improve understanding of E. ictaluri pathogenesis and persistence, and potential F. covae persistence in pond bottom sediments are needed.
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Affiliation(s)
- James T Tuttle
- Alabama Fish Farming Center, Greensboro, AL 36744, USA
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
| | - Timothy J Bruce
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
| | - Ian A E Butts
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
| | - Luke A Roy
- Alabama Fish Farming Center, Greensboro, AL 36744, USA
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
| | - Hisham A Abdelrahman
- Alabama Fish Farming Center, Greensboro, AL 36744, USA
- Department of Veterinary Hygiene and Management, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt
| | - Benjamin H Beck
- Aquatic Animal Health Research Unit, US Department of Agriculture, Agricultural Research Service, Auburn, AL 36832, USA
| | - Anita M Kelly
- Alabama Fish Farming Center, Greensboro, AL 36744, USA
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
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Nguyen DT, Marancik D, Soto E. B-glucan immunostilulation against columnaris in a white sturgeon (Acipenser transmontanus) model. FISH AND SHELLFISH IMMUNOLOGY REPORTS 2022; 3:100067. [DOI: 10.1016/j.fsirep.2022.100067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/11/2022] [Accepted: 08/22/2022] [Indexed: 11/17/2022] Open
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Runtuvuori-Salmela A, Kunttu H, Laanto E, Almeida G, Mäkelä K, Middelboe M, Sundberg LR. Prevalence of genetically similar Flavobacterium columnare phages across aquaculture environments reveals a strong potential for pathogen control. Environ Microbiol 2022; 24:2404-2420. [PMID: 35049114 PMCID: PMC9304149 DOI: 10.1111/1462-2920.15901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/11/2022] [Indexed: 11/28/2022]
Abstract
Intensive aquaculture conditions expose fish to bacterial infections, leading to significant financial losses, extensive antibiotic use and risk of antibiotic resistance in target bacteria. Flavobacterium columnare causes columnaris disease in aquaculture worldwide. To develop a bacteriophage‐based control of columnaris disease, we isolated and characterized 126 F. columnare strains and 63 phages against F. columnare from Finland and Sweden in 2017. Bacterial isolates were virulent on rainbow trout (Oncorhynchus mykiss) and fell into four previously described genetic groups A, C, E and G, with genetic groups C and E being the most virulent. Phage host range studied against a collection of 227 bacterial isolates (from 2013 to 2017) demonstrated modular infection patterns based on host genetic group. Phages infected contemporary and previously isolated bacterial hosts, but bacteria isolated most recently were generally resistant to previously isolated phages. Despite large differences in geographical origin, isolation year or host range of the phages, whole‐genome sequencing of 56 phages showed high level of genetic similarity to previously isolated F. columnare phages (Ficleduovirus, Myoviridae). Altogether, this phage collection demonstrates a potential for use in phage therapy.
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Affiliation(s)
- A Runtuvuori-Salmela
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Hmt Kunttu
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - E Laanto
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland.,Department Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - Gmf Almeida
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland.,Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - K Mäkelä
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - M Middelboe
- Department of Biology, Marine Biological Section, University of Copenhagen, Helsingør, Denmark
| | - L-R Sundberg
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
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7
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Type IX secretion system effectors and virulence of the model Flavobacterium columnare strain MS-FC-4. Appl Environ Microbiol 2021; 88:e0170521. [PMID: 34818105 DOI: 10.1128/aem.01705-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Flavobacterium columnare causes columnaris disease in wild and cultured freshwater fish and is a major problem for sustainable aquaculture worldwide. The F. columnare type IX secretion system (T9SS) secretes many proteins and is required for virulence. The T9SS component GldN is required for secretion and for gliding motility over surfaces. Genetic manipulation of F. columnare is inefficient, which has impeded identification of secreted proteins that are critical for virulence. Here we identified a virulent wild-type F. columnare strain (MS-FC-4) that is highly amenable to genetic manipulation. This facilitated isolation and characterization of two deletion mutants lacking core components of the T9SS. Deletion of gldN disrupted protein secretion and gliding motility and eliminated virulence in zebrafish and rainbow trout. Deletion of porV disrupted secretion and virulence but not motility. Both mutants exhibited decreased extracellular proteolytic, hemolytic, and chondroitin sulfate lyase activities. They also exhibited decreased biofilm formation and decreased attachment to fish fins and to other surfaces. Using genomic and proteomic approaches, we identified proteins secreted by the T9SS. We deleted ten genes encoding secreted proteins and characterized the virulence of mutants lacking individual or multiple secreted proteins. A mutant lacking two genes encoding predicted peptidases exhibited reduced virulence in rainbow trout, and mutants lacking a predicted cytolysin showed reduced virulence in zebrafish and rainbow trout. The results establish F. columnare strain MS-FC-4 as a genetically amenable model to identify virulence factors. This may aid development of measures to control columnaris disease and impact fish health and sustainable aquaculture. IMPORTANCE: Flavobacterium columnare causes columnaris disease in wild and aquaculture-reared freshwater fish and is a major problem for aquaculture. Little is known regarding the virulence factors involved in this disease and control measures are inadequate. The type IX secretion system (T9SS) secretes many proteins and is required for virulence, but the secreted virulence factors are not known. We identified a strain of F. columnare (MS-FC-4) that is well suited for genetic manipulation. The components of the T9SS and the proteins secreted by this system were identified. Deletion of core T9SS genes eliminated virulence. Genes encoding ten secreted proteins were deleted. Deletion of two peptidase-encoding genes resulted in decreased virulence in rainbow trout, and deletion of a cytolysin-encoding gene resulted in decreased virulence in rainbow trout and zebrafish. Secreted peptidases and cytolysins are likely virulence factors and are targets for the development of control measures.
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Growth of Flavobacterium columnare Genomovars in the Presence or Lack of Supplemental Cations. Curr Microbiol 2021; 78:2474-2480. [PMID: 33991203 DOI: 10.1007/s00284-021-02507-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 04/25/2021] [Indexed: 10/21/2022]
Abstract
Flavobacterium columnare is a problematic pathogen for the aquaculture industry where isolates are classified by genomovars. Suspended growth in a low nutrient media, like tryptone yeast extract salts, is a common method used for laboratory study. The presence of calcium and magnesium is the factor contributing to growth, virulence, and biofilm formation for F. columnare. Exponential growth occurs within 24 h for F. columnare when grown in complete tryptone yeast extract salts medium at 30 ºC. Withholding CaCl2 and MgSO4 components from a complete TYES formulation reduced or completely inhibited growth of genomovar I isolates but not the growth of genomovar II, IIB, or III isolates. Only 3 of 20 genomovar I isolates, MS-FC-4, FC-CSF-53, and 023-08-3, could achieve O.D. 540 readings ≥ 0.3 but only after 48-h incubation in cation-restricted TYES. Independently adding CaCl2 or MgSO4 to tryptone and yeast extracts did not result in a genomovar-specific growth phenotype, but generally demonstrated increased clumping with individual isolates presenting abnormal growth. Clumping formed filamentous strings that migrated to the top of the culture tube when isolates were grown in TYE+CaCl2. Several of the F. columnare isolates from all the genomovars exhibited delayed growth when a single cation source was provided. This study demonstrates phenotypic differences between and within genomovars of a single bacterial species when grown under different TYES media conditions.
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Sebastião FD, Shahin K, Heckman TI, LaFrentz BR, Griffin MJ, Loch TP, Mukkatira K, Veek T, Richey C, Adkison M, Holt RA, Soto E. Genetic characterization of Flavobacterium columnare isolates from the Pacific Northwest, USA. DISEASES OF AQUATIC ORGANISMS 2021; 144:151-158. [PMID: 33955853 DOI: 10.3354/dao03588] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Flavobacterium columnare is the causative agent of columnaris disease. Previous work has demonstrated a high degree of genetic variability among F. columnare isolates, identifying 4 genetic groups (GGs) with some host associations. Herein, a total of 49 F. columnare isolates were characterized, the majority of which were collected from 15 different locations throughout the US Pacific Northwest. Most isolates were collected from 2015-2018 and originated from disease outbreaks in salmonid hatcheries and rearing ponds, sturgeon hatcheries and ornamental fish. Other isolates were part of collections recovered from 1980-2018. Initial identification was confirmed by F. columnare species-specific qPCR. Study isolates were further characterized using a multiplex PCR that differentiates between the 4 currently recognized F. columnare GGs. Multiplex PCR results were supported by repetitive sequence-mediated PCR fingerprinting and gyrB sequence analysis. F. columnare GG1 was the most prevalent (83.7%, n = 41/49), represented by isolates from salmonids (n = 32), white sturgeon (n = 2), channel catfish (n = 1), ornamental goldfish (n = 1), koi (n = 3), wild sunfish (n = 1) and 1 unknown host. Six isolates (12.2%, n = 6/49) were identified as GG3, which were cultured from rainbow trout (n = 3) and steelhead trout (n = 3). Two isolates were identified as GG2 (4.1%, n = 2/49) and were from ornamental fish. No GG4 isolates were cultured in this study. The biological significance of this genetic variability remains unclear, but this variation could have significant implications for fish health management. The results from this study provide baseline data for future work developing strategies to ameliorate columnaris-related losses in the US Pacific Northwest.
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Affiliation(s)
- Fernanda de Sebastião
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, California 95616, USA
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10
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Evenhuis JP, Lipscomb R, Birkett C. Virulence variations of Flavobacterium columnare in rainbow trout (Oncorhynchus mykiss) eyed eggs and alevin. JOURNAL OF FISH DISEASES 2021; 44:533-539. [PMID: 33647180 DOI: 10.1111/jfd.13343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
Flavobacterium columnare (Fc) is the causative agent for columnaris disease (CD) in several fish species and an emerging problem for rainbow trout aquaculture. We characterize the virulence phenotype of two Fc isolates, CSF-298-10 and MS-FC-4, against trout from two sources, NCCCWA and a production stock (PS), at the eyed egg and alevin life stages. Immersion challenges demonstrated that NCCCWA eyed eggs were susceptible to the Fc isolate MS-FC-4 (>97% mortality) but no mortality was observed against PS eyed eggs. The CSF-298-10 had little effect on any eyed eggs tested and was not highly virulent to any alevin till day six post-hatch, up to 38% for NCCCWA and ~80% PS alevin. The MS-FC-4 strain produced ≥80% mortality any day an immersion challenge occurred post-hatch. Significant difference in CFU counts was recorded between the Fc strains on 2 days post-hatch immersion challenges. Counts for the NCCCWA alevin were 4.4 × 103 CFU/ml-1 and 1.8 × 106 CFU/ml-1 for the CSF-298-10 strain and MS-FC-4 strain, respectively, and for the PS alevin CSF-298-10 measured 9.9 × 101 CFU/ml-1 and 3.8 × 105 CFU/ml-1 for MS-FC-4. These two Fc isolates present stark differences in virulence phenotypes to both eyed eggs and alevin and present an interesting model system for virulence kinetics and potentially alternative pathogenic pathways.
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Affiliation(s)
- Jason P Evenhuis
- National Center for Cool and Cold Water Aquaculture USDA/ARS, Kearneysville, WV, USA
| | - Ryan Lipscomb
- National Center for Cool and Cold Water Aquaculture USDA/ARS, Kearneysville, WV, USA
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture USDA/ARS, Kearneysville, WV, USA
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Stressmann FA, Bernal-Bayard J, Perez-Pascual D, Audrain B, Rendueles O, Briolat V, Bruchmann S, Volant S, Ghozlane A, Häussler S, Duchaud E, Levraud JP, Ghigo JM. Mining zebrafish microbiota reveals key community-level resistance against fish pathogen infection. ISME JOURNAL 2020; 15:702-719. [PMID: 33077888 DOI: 10.1038/s41396-020-00807-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 09/30/2020] [Accepted: 10/05/2020] [Indexed: 02/08/2023]
Abstract
The long-known resistance to pathogens provided by host-associated microbiota fostered the notion that adding protective bacteria could prevent or attenuate infection. However, the identification of endogenous or exogenous bacteria conferring such protection is often hindered by the complexity of host microbial communities. Here, we used zebrafish and the fish pathogen Flavobacterium columnare as a model system to study the determinants of microbiota-associated colonization resistance. We compared infection susceptibility in germ-free, conventional and reconventionalized larvae and showed that a consortium of 10 culturable bacterial species are sufficient to protect zebrafish. Whereas survival to F. columnare infection does not rely on host innate immunity, we used antibiotic dysbiosis to alter zebrafish microbiota composition, leading to the identification of two different protection strategies. We first identified that the bacterium Chryseobacterium massiliae individually protects both larvae and adult zebrafish. We also showed that an assembly of 9 endogenous zebrafish species that do not otherwise protect individually confer a community-level resistance to infection. Our study therefore provides a rational approach to identify key endogenous protecting bacteria and promising candidates to engineer resilient microbial communities. It also shows how direct experimental analysis of colonization resistance in low-complexity in vivo models can reveal unsuspected ecological strategies at play in microbiota-based protection against pathogens.
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Affiliation(s)
- Franziska A Stressmann
- Genetics of Biofilms Laboratory, Institut Pasteur, UMR CNRS2001, 75015, Paris, France.,Department of Chemical Analytics and Biogeochemistry, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587, Berlin, Germany
| | - Joaquín Bernal-Bayard
- Genetics of Biofilms Laboratory, Institut Pasteur, UMR CNRS2001, 75015, Paris, France.,Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080, Sevilla, Spain
| | - David Perez-Pascual
- Genetics of Biofilms Laboratory, Institut Pasteur, UMR CNRS2001, 75015, Paris, France
| | - Bianca Audrain
- Genetics of Biofilms Laboratory, Institut Pasteur, UMR CNRS2001, 75015, Paris, France
| | - Olaya Rendueles
- Genetics of Biofilms Laboratory, Institut Pasteur, UMR CNRS2001, 75015, Paris, France.,Microbial Evolutionary Genomics Laboratory, Institut Pasteur, UMR3525, 75015, Paris, France
| | - Valérie Briolat
- Macrophages and Development of Immunity Laboratory, Institut Pasteur, UMR3738 CNRS, 75015, Paris, France
| | - Sebastian Bruchmann
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, UK
| | - Stevenn Volant
- Hub de Bioinformatique et Biostatistique - Département Biologie Computationnelle, Institut Pasteur, USR 3756 CNRS, Paris, France
| | - Amine Ghozlane
- Hub de Bioinformatique et Biostatistique - Département Biologie Computationnelle, Institut Pasteur, USR 3756 CNRS, Paris, France
| | - Susanne Häussler
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen, Denmark
| | - Eric Duchaud
- Unité VIM, INRAE, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Jean-Pierre Levraud
- Macrophages and Development of Immunity Laboratory, Institut Pasteur, UMR3738 CNRS, 75015, Paris, France
| | - Jean-Marc Ghigo
- Genetics of Biofilms Laboratory, Institut Pasteur, UMR CNRS2001, 75015, Paris, France.
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12
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Abdelhamed H, Nho SW, Karsi A, Lawrence ML. The role of denitrification genes in anaerobic growth and virulence of Flavobacterium columnare. J Appl Microbiol 2020; 130:1062-1074. [PMID: 32955778 DOI: 10.1111/jam.14855] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 11/28/2022]
Abstract
AIMS Comparative genomics analyses indicated that the Flavobacterium columnare genome has unique denitrification genes relative to Flavobacterium psychrophilum and Flavobacterium johnsoniae, including nasA (nitrate reductase), nirS (nitrite reductase), norB (nitric oxide reductase) and nosZ (nitrous oxide reductase). The current study determines the roles of nasA, nirS, norB and nosZ in anaerobic growth, nitrate reduction, biofilm formation and virulence. METHODS AND RESULTS Four in-frame deletion mutants in virulent F. columnare strain 94-081 were constructed by allelic exchange using pCP29 plasmid. Compared with parent strain 94-081, FcΔnasA,FcΔnirS and FcΔnosZ mutants did not grow as well anaerobically, whereas the growth of FcΔnorB strain was similar to the parent strain (FcWT). Exogenous nitrate was not significantly consumed under anaerobic conditions in FcΔnasA, FcΔnirS and FcΔnosZ compared to parent strain 94-081. Under anaerobic conditions, Fc∆nasA, Fc∆norB and Fc∆nosZ formed significantly less biofilm than the wild type strain at 24 and 96 h, but FcΔnirS was not significantly affected. The nitrite reductase mutant FcΔnirS was highly attenuated in catfish, whereas FcΔnasA, FcΔnorB and FcΔnosZ had similar virulence to FcWT. CONCLUSIONS These results show, for the first time, that denitrification genes enable F. columnare to grow anaerobically using nitrate as an electron acceptor, and nitrite reductase contributes to F. columnare virulence. SIGNIFICANCE AND IMPACT OF THE STUDY These findings indicate potential for F. columnare to grow in nitrate-rich anaerobic zones in catfish production ponds, and they suggest that a Fc∆nirS strain could be useful as a safe live vaccine if it protects catfish against columnaris disease.
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Affiliation(s)
- H Abdelhamed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - S W Nho
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - A Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - M L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
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13
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Kayansamruaj P, Areechon N, Unajak S. Development of fish vaccine in Southeast Asia: A challenge for the sustainability of SE Asia aquaculture. FISH & SHELLFISH IMMUNOLOGY 2020; 103:73-87. [PMID: 32335313 DOI: 10.1016/j.fsi.2020.04.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 02/23/2020] [Accepted: 04/15/2020] [Indexed: 05/08/2023]
Abstract
Southeast (SE) Asia plays an important role in global food security as this region has been regarded as one of the major producers of aquaculture product and, to date, freshwater fish accounted for one-third of the total aquaculture in SE Asia. The intensification of freshwater farming corresponding to increase of consumer demands has inevitably led to the emergence and re-emergence of diseases causing tremendous economic loss in the region. Nile tilapia (Oreochromis niloticus) and striped catfish (Pangasianodon hypophthalmus), the major freshwater fish species of SE Asia, have been reported susceptible to several bacterial pathogens, e.g. Streptococcus agalactiae, Edwardsiella ictalurid and Flavobacterium columnare. Since only a limited number of vaccines being registered and marketed, these pathogenic organisms still represent a severe threat to aquaculture industry in SE Asia. However, there is profound advancement in the understanding of disease epidemiology, pathogenic mechanisms, teleost mucosal immunity and vaccine delivery system over the last few years. This review aimed to summarize those recent findings which hopefully can provide novel insight into the future development of suitable vaccine and vaccination regime against bacterial infection in SE Asia region.
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Affiliation(s)
- Pattanapon Kayansamruaj
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, 10900, Chatuchak, Bangkok, Thailand.
| | - Nontawith Areechon
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, 10900, Chatuchak, Bangkok, Thailand
| | - Sasimanas Unajak
- Department of Biochemistry, Faculty of Science, Kasetsart University, 10900, Chatuchak, Bangkok, Thailand.
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14
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LaFrentz BR, García JC, Shelley JP. Multiplex PCR for genotyping Flavobacterium columnare. JOURNAL OF FISH DISEASES 2019; 42:1531-1542. [PMID: 31469439 DOI: 10.1111/jfd.13068] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/16/2019] [Accepted: 07/17/2019] [Indexed: 06/10/2023]
Abstract
Recent research has identified four distinct genetic groups among isolates of Flavobacterium columnare through multilocus phylogenetic analyses; however, there are no quick methods to determine the genotype of an isolate. The objective of this research was to develop a multiplex PCR to rapidly genotype F. columnare to genetic group. Comparative bacterial genomics was used to identify regions in the genomes unique to each genetic group, and primers were designed to specifically amplify different sized amplicons for each genetic group. The optimized assay was demonstrated to be specific for each genetic group and F. columnare, and no specific amplicons were generated using gDNA from a panel of other Flavobacterium spp. and bacterial fish pathogens. The analytical sensitivity of the assay ranged from 209 to 883 genome equivalents depending on the genetic group. The multiplex PCR was evaluated by genotyping a panel of 22 unknown F. columnare isolates and performing DNA sequencing of the dnaK gene in parallel. The results demonstrated 100% accordance between multiplex PCR results and assignment to genetic group via phylogenetic analysis. The multiplex PCR provides a useful tool for assigning an unknown isolate to genetic group and may be used to determine which genetic groups of F. columnare are circulating and most predominant in different aquaculture industries.
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Affiliation(s)
- Benjamin R LaFrentz
- Aquatic Animal Health Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Auburn, AL, USA
| | - Julio C García
- Aquatic Animal Health Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Auburn, AL, USA
| | - John P Shelley
- Aquatic Animal Health Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Auburn, AL, USA
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15
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Branchial bioenergetics dysfunction as a relevant pathophysiological mechanism in freshwater silver catfish (Rhamdia quelen) experimentally infected with Flavobacterium columnare. Microb Pathog 2019; 138:103817. [PMID: 31672529 DOI: 10.1016/j.micpath.2019.103817] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/21/2019] [Accepted: 10/21/2019] [Indexed: 01/20/2023]
Abstract
Flavobacterium columnare, the causative agent of columnaris disease, is a serious bacterial disease responsible for causing devastating mortality rates in several species of freshwater fish, leading to severe economic losses in the aquaculture industry. Notwithstanding the enormous impacts this disease can have, very little is known regarding the interaction between the host and bacterium in terms of the mortality rate of silver catfish (Rhamdia quelen), as well its linkage to gill energetic homeostasis. Therefore, we conducted independent experiments to evaluate the mortality rates caused by F. columnare in silver catfish, as well as whether columnaris disease impairs the enzymes of the phosphoryl transfer network in gills of silver catfish and the pathways involved in this inhibition. Experiment I revealed that clinical signs started to appear 72 h post-infection (hpi), manifesting as lethargy, skin necrosis, fin erosion and gill discoloration. Silver catfish began to die at 96 hpi, and 100% mortality was observed at 120 hpi. Experiment II revealed that creatine kinase (CK, cytosolic and mitochondrial) and pyruvate kinase (PK) activities were inhibited in silver catfish experimentally infected with F. columnare, while no significant difference was observed between experimental and control groups with respect to adenylate kinase activity. Activity of the branchial sodium-potassium pump (Na+, K+-ATPase) was inhibited while reactive oxygen species (ROS) and lipid peroxidation levels were higher in silver catfish experimentally infected with F. columnare than in the control group at 72 hpi. Based on these data, the impairment of CK activity elicited by F. columnare caused a disruption in branchial energetic balance, possibly reducing ATP availability in the gills and provoking impairment of Na+, K +ATPase activity. The inhibition of CK and PK activities appears to be mediated by ROS overproduction and lipid peroxidation, both of which contribute to disease pathogenesis associated with branchial tissue.
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16
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Draft Genome Sequences of Flavobacterium columnare Strains ARS1 and BGFS27, Isolated from Channel Catfish ( Ictalurus punctatus). Microbiol Resour Announc 2019; 8:8/26/e00648-19. [PMID: 31248995 PMCID: PMC6597689 DOI: 10.1128/mra.00648-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Flavobacterium columnare strain BGFS27 was isolated from an apparently healthy wild channel catfish (Ictalurus punctatus) collected from the Mobile River in 2005. F. columnare strain ARS1 was isolated from a channel catfish suffering from columnaris disease in a commercial farm in 1996. BGFS27 belongs to genomovar II (genetic group 2), while ARS1 belongs to genomovar III (genetic group 3). Here, we report the draft genome sequences of F. columnare BGFS27 and ARS1, obtained by PacBio sequencing.
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17
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LaFrentz BR, García JC, Waldbieser GC, Evenhuis JP, Loch TP, Liles MR, Wong FS, Chang SF. Identification of Four Distinct Phylogenetic Groups in Flavobacterium columnare With Fish Host Associations. Front Microbiol 2018; 9:452. [PMID: 29593693 PMCID: PMC5859164 DOI: 10.3389/fmicb.2018.00452] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/27/2018] [Indexed: 12/04/2022] Open
Abstract
Columnaris disease, caused by the Gram-negative bacterium Flavobacterium columnare, is one of the most prevalent fish diseases worldwide. An exceptionally high level of genetic diversity among isolates of F. columnare has long been recognized, whereby six established genomovars have been described to date. However, little has been done to quantify or characterize this diversity further in a systematic fashion. The objective of this research was to perform phylogenetic analyses of 16S rRNA and housekeeping gene sequences to decipher the genetic diversity of F. columnare. Fifty isolates and/or genomes of F. columnare, originating from diverse years, geographic locations, fish hosts, and representative of the six genomovars were analyzed in this study. A multilocus phylogenetic analysis (MLPA) of the 16S rRNA and six housekeeping genes supported four distinct F. columnare genetic groups. There were associations between genomovar and genetic group, but these relationships were imperfect indicating that genomovar assignment does not accurately reflect F. columnare genetic diversity. To expand the dataset, an additional 90 16S rRNA gene sequences were retrieved from GenBank and a phylogenetic analysis of this larger dataset also supported the establishment of four genetic groups. Examination of isolate historical data indicated biological relevance to the identified genetic diversity, with some genetic groups isolated preferentially from specific fish species or families. It is proposed that F. columnare isolates be assigned to the four genetic groups defined in this study rather than genomovar in order to facilitate a standard nomenclature across the scientific community. An increased understanding of which genetic groups are most prevalent in different regions and/or aquaculture industries may allow for the development of improved targeted control and treatment measures for columnaris disease.
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Affiliation(s)
- Benjamin R LaFrentz
- Aquatic Animal Health Research Unit, United States Department of Agriculture - Agricultural Research Service, Auburn, AL, United States
| | - Julio C García
- Aquatic Animal Health Research Unit, United States Department of Agriculture - Agricultural Research Service, Auburn, AL, United States
| | - Geoffrey C Waldbieser
- Warmwater Aquaculture Research Unit, Thad Cochran National Warmwater Aquaculture Center, United States Department of Agriculture - Agricultural Research Service, Stoneville, MS, United States
| | - Jason P Evenhuis
- National Center for Cool and Cold Water Aquaculture, United States Department of Agriculture - Agricultural Research Service, Kearneysville, WV, United States
| | - Thomas P Loch
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
| | - Mark R Liles
- Department of Biological Sciences, Auburn University, Auburn, AL, United States
| | - Fong S Wong
- MSD Animal Health Innovation Pte. Ltd., Singapore, Singapore
| | - Siow F Chang
- MSD Animal Health Innovation Pte. Ltd., Singapore, Singapore
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