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A panoptic review of techniques for finfish disease diagnosis: The status quo and future perspectives. J Microbiol Methods 2022; 196:106477. [DOI: 10.1016/j.mimet.2022.106477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/21/2022] [Accepted: 04/21/2022] [Indexed: 12/27/2022]
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The Use of Extracellular Membrane Vesicles for Immunization against Francisellosis in Nile Tilapia ( Oreochromis niloticus) and Atlantic Cod ( Gadus morhua L.). Vaccines (Basel) 2021; 9:vaccines9010034. [PMID: 33435503 PMCID: PMC7827370 DOI: 10.3390/vaccines9010034] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 11/17/2022] Open
Abstract
Francisellosis in fish is caused by the facultative intracellular Gram-negative bacterial pathogens Francisella noatunensis ssp. noatunensis and Francisella orientalis. The disease is affecting both farmed and wild fish worldwide and no commercial vaccines are currently available. In this study, we tested isolated membrane vesicles (MVs) as possible vaccine candidates based on previous trials in zebrafish (Danio rerio) indicating promising vaccine efficacy. Here, the MV vaccine-candidates were tested in their natural hosts, Atlantic cod (Gadus morhua L.) and Nile tilapia (Oreochromis niloticus). Injection of MVs did not display any toxicity or other negative influence on the fish and gene expression analysis indicated an influence on the host immune response. However, unlike in other tested fish species, a protective immunity following vaccine application and immunization period could not be detected in the Atlantic cod or tilapia. Further in vivo studies are required to achieve a better understanding of the development of immunological memory in different fish species.
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Shahin K, Pirezan F, Rogge M, LaFrentz BR, Shrestha RP, Hildebrand M, Lu F, HogenEsch H, Soto E. Development of IglC and GroEL recombinant vaccines for francisellosis in Nile tilapia, Oreochromis niloticus. FISH & SHELLFISH IMMUNOLOGY 2020; 105:341-349. [PMID: 32712230 DOI: 10.1016/j.fsi.2020.07.045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/14/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
Warm-water piscine francisellosis is a granulomatous bacterial disease caused by Francisella orientalis (Fo). The disease has been detected in a wide range of fish species globally, causing mortalities as high as 90% and significant economic losses. Currently there are no commercially available vaccines and few treatment options exist. In the current study, two novel recombinant vaccines were prepared using diatom-expressed IglC or bacterial-expressed GroEL proteins. The vaccine antigens were emulsified with either nanoparticles or a commercially available oil-based adjuvant. Nile tilapia, Oreochromis niloticus, fingerlings were immunized intracoelomically with the recombinant IglC or GroEL vaccines, diatoms alone or phosphate buffer saline. Approximately 840-degree days post-vaccination, fish were challenged via immersion with 106 CFU/mL of wild-type Fo. Twenty-one days post challenge (dpc), the highest relative percent survival was recorded in the IglC-Montanide group (75%), compared to 53%, 50%, 22%, 19% and 16% in the IglC-nanoparticles, GroEL-Montanide, GroEL-nanoparticles, diatoms-Montanide and diatoms-nanoparticles groups, respectively. Protection correlated with significantly higher specific antibody responses in the IglC-Montanide group. Moreover, a significantly lower bacterial load was detected in spleen samples from the IglC-Montanide survivor tilapia compared to the other experimental groups. This is the first report of recombinant vaccines against piscine francisellosis in tilapia. The Fo vaccines described in our study may facilitate development of a safe, cost-effective and highly protective vaccine against francisellosis in farmed tilapia.
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Affiliation(s)
- Khalid Shahin
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, 95616, Davis, CA, USA
| | - Felipe Pirezan
- Department of Veterinary Clinics and Surgery, School of Veterinary Medicine, Federal University of Minas Gerais, 31270-901, Belo Horizonte, MG, Brazil
| | - Matt Rogge
- Department of Biology, University of Wisconsin-Stevens Point, Stevens Point, WI, USA
| | | | - Roshan P Shrestha
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Mark Hildebrand
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Fangjia Lu
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Harm HogenEsch
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Esteban Soto
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, 95616, Davis, CA, USA.
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Nguyen VV, Dong HT, Senapin S, Gangnonngiw W, Pirarat N, Kayansamruaj P, Rung-Ruangkijkrai T, Rodkhum C. Transmission of Francisella noatuensis subsp. orientalis from subclinically infected hybrid red tilapia broodstock (Oreochromis sp.) to their offspring. Microb Pathog 2019; 136:103670. [PMID: 31430526 DOI: 10.1016/j.micpath.2019.103670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 05/27/2019] [Accepted: 08/13/2019] [Indexed: 11/15/2022]
Abstract
Francisella noatunensis subsp. orientalis (Fno) has been reported as an important bacterial pathogen causing significant mortality (30-95%) in farmed tilapia in broad geographic areas. However, we found that there was a proportion of broodfish in our laboratory that appeared to be healthy but which tested positive for Fno. We therefore hypothesized that Fno might be able to be transmitted from subclinically infected tilapia mouthbrooders to their offspring through the current practice of fry production in tilapia hatcheries. To prove this, experimentally infected hybrid red tilapia broodstock were mated and their offspring were examined for the presence of Fno. In this study, three pairs of infected broodfish were mated for natural spawning and fertilized eggs from each couple were then collected from the female mouths for artificial incubation. The newly hatched larvae were cultured for 30 days and sample collection was performed at different developmental stages i.e. yolk-sac larvae, 5 and 30-day old fry. The results showed that the ovary and testis of all 3 pairs of the broodstock, as well as their fertilized eggs and offspring were Fno positive by Fno-specific PCR and in situ DNA hybridization. In summary, this study revealed that with the current practice in tilapia hatcheries, Fno might be able to transmit from subclinically infected tilapia mouthbrooders to their offspring. Therefore, using Fno-free broodfish in tilapia hatcheries should be considered in order to produce Fno-free tilapia fry.
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Affiliation(s)
- Vuong Viet Nguyen
- Department of Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand; Research Institute of Aquaculture No. 1 (RIA1), Dinh Bang, Tu Son, Bac Ninh, Viet Nam
| | - Ha Thanh Dong
- Faculty of Science and Technology, Suan Sunandha Rajabhat University, Bangkok, Thailand.
| | - Saengchan Senapin
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, Thailand; Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Warachin Gangnonngiw
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, Thailand; Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Nopadon Pirarat
- Department of Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | | | - Tilladit Rung-Ruangkijkrai
- Department of Veterinary Anatomy, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Channarong Rodkhum
- Department of Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand; Fish Infectious Diseases Research Unit (FID RU), Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
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5
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Ramírez-Paredes JG, Mendoza-Roldan MA, Lopez-Jimena B, Shahin K, Metselaar M, Thompson KD, Penman DJ, Richards RH, Adams A. Whole cell inactivated autogenous vaccine effectively protects red Nile tilapia (Oreochromis niloticus) against francisellosis via intraperitoneal injection. JOURNAL OF FISH DISEASES 2019; 42:1191-1200. [PMID: 31184398 DOI: 10.1111/jfd.13041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/03/2019] [Accepted: 05/07/2019] [Indexed: 06/09/2023]
Abstract
Francisella noatunensis subsp. orientalis is a pathogen of tilapia and other warm-water fish for which no vaccines are commercially available. In this study, a whole cell formalin-inactivated vaccine was developed for the first time using the highly virulent isolate STIR-GUS-F2f7 and the oil-based adjuvant Montanide™ ISA 763A VG. The efficacy of the vaccine was assessed in red Nile tilapia via intraperitoneal (i.p.) injection using homologous experimental infection and correlates of protection such as seral antibody production and bacterial loads in the spleen. For immunization, fish were i.p. injected with 0.1 ml of the vaccine, the adjuvant alone or PBS. At 840 degree days post-vaccination, all fish were i.p. injected with 4.0 × 103 CFU/fish of pathogenic bacteria. The RPS at the end of the trial was 100% in the vaccinated group with significantly higher survival than in the adjuvant and control groups. The RPS in the adjuvant group was 42%, and no significant difference was seen in survival between this and the PBS group. Moreover, significantly higher antibody titres in the serum and significantly lower bacterial loads in the spleen were detected in the vaccinated fish by ELISA and qPCR, respectively. These findings highlight the potential of autogenous vaccines for controlling francisellosis in tilapia.
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Affiliation(s)
| | | | - Benjamin Lopez-Jimena
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, UK
| | - Khalid Shahin
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, UK
| | | | - Kim D Thompson
- Aquaculture Research Group, Moredun Research Institute, Edinburgh, UK
| | - David J Penman
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, UK
| | - Randolph H Richards
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, UK
| | - Alexandra Adams
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, UK
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Shahin K, Shinn AP, Metselaar M, Ramirez-Paredes JG, Monaghan SJ, Thompson KD, Hoare R, Adams A. Efficacy of an inactivated whole-cell injection vaccine for nile tilapia, Oreochromis niloticus (L), against multiple isolates of Francisella noatunensis subsp. orientalis from diverse geographical regions. FISH & SHELLFISH IMMUNOLOGY 2019; 89:217-227. [PMID: 30951851 DOI: 10.1016/j.fsi.2019.03.071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 03/26/2019] [Accepted: 03/28/2019] [Indexed: 06/09/2023]
Abstract
Francisellosis, induced by Francisella noatunensis subsp. orientalis (Fno), is an emerging bacterial disease representing a major threat to the global tilapia industry. There are no commercialised vaccines presently available against francisellosis for use in farmed tilapia, and the only available therapeutic practices used in the field are either the prolonged use of antibiotics or increasing water temperature. Recently, an autogenous whole cell-adjuvanted injectable vaccine was developed that gave 100% relative percent survival (RPS) in tilapia challenged with a homologous isolate of Fno. In this study, we evaluated the efficacy of this vaccine against challenge with heterologous Fno isolates. Healthy Nile tilapia, Oreochromis niloticus (∼15 g) were injected intraperitoneally (i.p.) with the vaccine, adjuvant-alone or phosphate buffer saline (PBS) followed by an i.p. challenge with three Fno isolates from geographically distinct locations. The vaccine provided significant protection in all groups of vaccinated tilapia, with a significantly higher RPS of 82.3% obtained against homologous challenge, compared to 69.8% and 65.9% with the heterologous challenges. Protection correlated with significantly higher specific antibody responses, and western blot analysis demonstrated cross-isolate antigenicity with fish sera post-vaccination and post-challenge. Moreover, a significantly lower bacterial burden was detected by qPCR in conjunction with significantly greater expression of IgM, IL-1 β, TNF-α and MHCII, 72 h post-vaccination (hpv) in spleen samples from vaccinated tilapia compared to fish injected with adjuvant-alone and PBS. The Fno vaccine described in this study may provide a starting point for development a broad-spectrum highly protective vaccine against francisellosis in tilapia.
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Affiliation(s)
- Khalid Shahin
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK; Aquatic Animal Diseases Lab, Aquaculture Department, National Institute of Oceanography and Fisheries (NIOF), P.O. Box 43511, Suez, Egypt.
| | - Andrew P Shinn
- Fish Vet Group Asia, 21/359 Premjairard Road, Chonburi, 20130, Thailand
| | - Matthijs Metselaar
- Benchmark Animal Health, Bush House, Edinburgh Technopole, Midlothian, Edinburgh, EH26 0BB, UK
| | | | - Sean J Monaghan
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Kim D Thompson
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian, EH26 0PZ, UK
| | - Rowena Hoare
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Alexandra Adams
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
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Shahin K, Gustavo Ramirez-Paredes J, Harold G, Lopez-Jimena B, Adams A, Weidmann M. Development of a recombinase polymerase amplification assay for rapid detection of Francisella noatunensis subsp. orientalis. PLoS One 2018; 13:e0192979. [PMID: 29444148 PMCID: PMC5812721 DOI: 10.1371/journal.pone.0192979] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 02/01/2018] [Indexed: 11/18/2022] Open
Abstract
Francisella noatunensis subsp. orientalis (Fno) is the causative agent of piscine francisellosis in warm water fish including tilapia. The disease induces chronic granulomatous inflammation with high morbidity and can result in high mortality. Early and accurate detection of Fno is crucial to set appropriate outbreak control measures in tilapia farms. Laboratory detection of Fno mainly depends on bacterial culture and molecular techniques. Recombinase polymerase amplification (RPA) is a novel isothermal technology that has been widely used for the molecular diagnosis of various infectious diseases. In this study, a recombinase polymerase amplification (RPA) assay for rapid detection of Fno was developed and validated. The RPA reaction was performed at a constant temperature of 42°C for 20 min. The RPA assay was performed using a quantitative plasmid standard containing a unique Fno gene sequence. Validation of the assay was performed not only by using DNA from Fno, closely related Francisella species and other common bacterial pathogens in tilapia farms, but also by screening 78 Nile tilapia and 5 water samples. All results were compared with those obtained by previously established real-time qPCR. The developed RPA showed high specificity in detection of Fno with no cross-detection of either the closely related Francisella spp. or the other tested bacteria. The Fno-RPA performance was highly comparable to the published qPCR with detection limits at 15 and 11 DNA molecules detected, respectively. The RPA gave quicker results in approximately 6 min in contrast to the qPCR that needed about 90 min to reach the same detection limit, taking only 2.7–3 min to determine Fno in clinical samples. Moreover, RPA was more tolerant to reaction inhibitors than qPCR when tested with field samples. The fast reaction, simplicity, cost-effectiveness, sensitivity and specificity make the RPA an attractive diagnostic tool that will contribute to controlling the infection through prompt on-site detection of Fno.
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Affiliation(s)
- Khalid Shahin
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
- Aquatic Animal Diseases Lab, Division of Aquaculture, National Institute of Oceanography and Fisheries, Suez, Egypt
- * E-mail:
| | - Jose Gustavo Ramirez-Paredes
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
| | - Graham Harold
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
| | - Benjamin Lopez-Jimena
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
| | - Alexandra Adams
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
| | - Manfred Weidmann
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
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Carraro R, Dalla Rovere G, Ferraresso S, Carraro L, Franch R, Toffan A, Pascoli F, Patarnello T, Bargelloni L. Development of a real-time PCR assay for rapid detection and quantification of Photobacterium damselae subsp. piscicida in fish tissues. JOURNAL OF FISH DISEASES 2018; 41:247-254. [PMID: 28857188 DOI: 10.1111/jfd.12703] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 07/11/2017] [Accepted: 07/14/2017] [Indexed: 06/07/2023]
Abstract
The availability of a rapid and accurate method for the diagnosis of Photobacterium damselae subsp. piscicida (Phdp), able to discriminate its strictly correlated subsp. damselae (Phdd), formally known as Vibrio damsela, is essential for managing fish pasteurellosis outbreaks in farmed fish. A single-step, high-sensitivity real-time PCR assay for simultaneous detection and quantification of P. damselae was designed targeting partial of the sequence of the bamB gene and tested for specificity and sensitivity on laboratory-generated samples as well as on experimentally infected seabream tissue samples. With a limit of detection (LOD) of one copy in pure bacterial DNA, the sensitivity was higher than all methods previously reported. Validation in target and non-target bacterial species proved the assay was able to discriminate Phdd-Phdp subspecies from diverse hosts/geographical origins and between non-target species. In addition, two SNPs in the target amplicon region determine two distinctive qPCR dissociation curves distinguishing between Phdp-Phdd. This is the first time that a molecular method for P. damselae diagnosis combines detection, quantification and subspecies identification in one step. The assay holds the potential to improve the knowledge of infection dynamics and the development of better strategies to control an important fish disease.
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Affiliation(s)
- R Carraro
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, Legnaro, Italy
| | - G Dalla Rovere
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, Legnaro, Italy
| | - S Ferraresso
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, Legnaro, Italy
| | - L Carraro
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, Legnaro, Italy
| | - R Franch
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, Legnaro, Italy
| | - A Toffan
- Fish Virology Department, National Reference Laboratory for Fish, Crustacean and Mollusc Diseases, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - F Pascoli
- Fish Virology Department, National Reference Laboratory for Fish, Crustacean and Mollusc Diseases, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - T Patarnello
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, Legnaro, Italy
| | - L Bargelloni
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, Legnaro, Italy
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Ramírez-Paredes JG, Thompson KD, Metselaar M, Shahin K, Soto E, Richards RH, Penman DJ, Colquhoun DJ, Adams A. A Polyphasic Approach for Phenotypic and Genetic Characterization of the Fastidious Aquatic Pathogen Francisella noatunensis subsp. orientalis. Front Microbiol 2017; 8:2324. [PMID: 29312155 PMCID: PMC5733052 DOI: 10.3389/fmicb.2017.02324] [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: 03/16/2017] [Accepted: 11/10/2017] [Indexed: 12/04/2022] Open
Abstract
Francisella noatunensis subsp. orientalis (Fno) is the causative agent of piscine francisellosis, an emerging infectious disease in Asia and Latin America. In this study two outbreaks of francisellosis were diagnosed in the UK on the basis of histopathology, electron microscopy, PCR, bacterial isolation and fulfillment of Koch's postulates. Furthermore, a phenotypic fingerprint based on biochemical analyses, metabolic activity, chemotaxonomic composition, and antimicrobial assays was generated for the novel isolates, the Fno type strain Ehime-1 from Asia and other Fno from Latin America. The genetic relatedness between the novel Fno and other Francisellaceae species was investigated by sequencing and comparing the 16SrRNA gene, 8 housekeeping genes (individually and concatenated) and the 16SrRNA-ITS-23SrRNA sequence. The phenotypic profiling indicated a high degree of similarity among the Fno strains as all were able to metabolize dextrin, N-acetyl-D glucosamine, D-fructose, α-D-glucose, D-mannose, methyl pyruvate, acetic acid, α-keto butyric acid, L-alaninamide, L-alanine, L-alanylglycine, L-asparagine, L-glutamic acid, L-proline, L-serine, L-threonine, inosine, uridine, glycerol, D L-α-glycerol phosphate, glucose-1-phosphate, and glucose-6-phosphate. The chemotaxonomic analyses indicated that 24:1 (20.3%), 18:1n-9 (16.9%), 24:0 (13.1%) 14:0 (10.9%), 22:0 (7.8%), 16:0 (7.6%), and 18:0 (5.5%) were the predominant structural fatty acids in Fno. The antimicrobial assays showed little variation between the isolates and high susceptibility to enrofloxacin, gentamicin, neomycin, streptomycin, amikacin, ciprofloxacin, gatifloxacin, nitrofurantoin, tobramycin, kanamycin, tetracycline, oxytetracycline, florfenicol, oxolinic acid, and streptomycin in all the Fno analyzed. In all the phylogenetic trees the Fno strains clustered together in independent branches confirming a high degree of homogeneity. Interestingly in five of the 11 trees i.e., mutS, putA, rpoB, 16SrRNA-ITS-23SrRNA, and concatenated sequence the two Francisella noatunensis ssp. diverged more from each other than from the closely related Francisella philomiragia (Fp). The phenotypic and genetic characterization confirmed the Fno isolates represent a solid phylo-phenetic taxon that in the current context of the genus seems to be misplaced within the species Fn. We propose the use of the present polyphasic approach in future studies to characterize strains of Fnn and Fp and verify their current taxonomic rank of Fno and other aquatic Francisella spp.
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Affiliation(s)
- José G. Ramírez-Paredes
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
| | - Kim D. Thompson
- Aquaculture Research Group, Moredun Research Institute, Edinburgh, United Kingdom
| | | | - Khalid Shahin
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
| | - Esteban Soto
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Randolph H. Richards
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
| | - David J. Penman
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
| | | | - Alexandra Adams
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
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Francisella noatunensis subspecies noatunensis clpB deletion mutant impairs development of francisellosis in a zebrafish model. Vaccine 2017; 35:7264-7272. [PMID: 29153776 DOI: 10.1016/j.vaccine.2017.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/01/2017] [Accepted: 11/06/2017] [Indexed: 12/14/2022]
Abstract
BACKGROUND Francisella noatunensis ssp. noatunensis (F.n.n.) is the causative agent of francisellosis in Atlantic cod and constitutes one of the main challenges for future aquaculture on this species. A facultative intracellular bacterium like F.n.n. exert an immunologic challenge against which live attenuated vaccines in general are most effective. Thus, we constructed a deletion in the F.n.n. clpB gene as ΔclpB mutants are among the most promising vaccine candidates in human pathogenic Francisella. PURPOSE Characterization of F.n.n. ΔclpB using primary Atlantic cod head kidney leukocytes, the zebrafish embryo and adult zebrafish model with focus on potential attenuation, relevant immune responses and immunogenic potential. MAIN RESULTS Interleukin 1 beta transcription in Atlantic cod leukocytes was significantly elevated from 24 to 96 h post infection with F.n.n. ΔclpB compared to F.n.n. wild-type (wt). Growth attenuation of the deletion mutant in zebrafish embryos was observed by fluorescence microscopy and confirmed by genome quantification by qPCR. In the immunization experiment, adult zebrafish were immunized with 7 × 106 CFU of F.n.n. ΔclpB before challenge four weeks later with 6 × 108 CFU of F.n.n. wt. One day after challenge, immunized zebrafish responded with significantly lower interleukin 8 levels compared to the non-immunized control. Immunized fish were protected against the acute mortality observed in non-immunized zebrafish after challenge and bacterial genomes quantified by qPCR were reduced to a minimum 28 days post challenge, indicating protective immunity stimulated by F.n.n. ΔclpB. CONCLUSION Deletion mutation of clpB in F.n.n. causes in vitro and in vivo attenuation and elicits a protective immune response in adult zebrafish against a lethal dose of F.n.n. wt. Taken together, the results presented increases the knowledge on protective immune responses against F.n.n.
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Lampe EO, Tandberg JI, Rishovd AL, Winther-Larsen HC. Francisella noatunensis ssp. noatunensis iglC deletion mutant protects adult zebrafish challenged with acute mortality dose of wild-type strain. DISEASES OF AQUATIC ORGANISMS 2017; 123:123-140. [PMID: 28262634 DOI: 10.3354/dao03087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The intracellular fish pathogen Francisella noatunensis remains an unsolved problem for aquaculture worldwide and an efficient vaccine is needed. In Francisella sp., IglC is an important virulence factor necessary for intracellular growth and escape from phagolysosomes. Deletion of the intracellular growth locus C (iglC) in Francisella sp. causes attenuation, but vaccine potential has only been attributed to ΔiglC from Francisella noatunensis ssp. orientalis, a warm-water fish pathogen. A ΔiglC mutant was constructed in the cold-water fish pathogen F. noatunensis ssp. noatunensis (Fnn), which causes francisellosis in Atlantic cod; the mutant was assessed in primary head kidney leucocytes from Atlantic cod. Fluorescence microscopy revealed reduced growth, while qPCR revealed an initial increase followed by a reduction in mutant genomes. Mutant-infected cod leucocytes presented higher interleukin 1 beta (il1β) and interleukin 8 (il8) transcription than wild-type (WT)-infected cells. Two doses of mutant and WT were tested in an adult zebrafish model whereupon 3 × 109 CFU caused acute disease and 3 × 107 CFU caused low mortality regardless of strain. However, splenomegaly developed only in the WT-infected zebrafish. Immunization with 7 × 106 CFU of Fnn ΔiglC protected zebrafish against challenge with a lethal dose of Fnn WT, and bacterial load was minimized within 28 d. Immunized fish had lower interleukin 6 (il6) and il8 transcription in kidney and prolonged interferon-gamma (ifng) transcription in spleens after challenge compared with non-immunized fish. Our data suggest an immunogenic potential of Fnn ΔiglC and indicate important cytokines associated with francisellosis pathogenesis and protection.
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Affiliation(s)
- Elisabeth O Lampe
- Center for Integrative Microbiology and Evolution, Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, 0316 Oslo, Norway
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Lai XH, Zhao LF, Chen XM, Ren Y. Rapid Identification and Characterization of Francisella by Molecular Biology and Other Techniques. Open Microbiol J 2016; 10:64-77. [PMID: 27335619 PMCID: PMC4899538 DOI: 10.2174/1874285801610010064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/20/2015] [Accepted: 10/22/2015] [Indexed: 11/22/2022] Open
Abstract
Francisella tularensis is the causative pathogen of tularemia and a
Tier 1 bioterror agent on the CDC list. Considering the fact that some
subpopulation of the F. tularensis strains is more virulent, more
significantly associated with mortality, and therefore poses more threat to
humans, rapid identification and characterization of this subpopulation strains
is of invaluable importance. This review summarizes the up-to-date developments
of assays for mainly detecting and characterizing F. tularensis and a
touch of caveats of some of the assays.
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Affiliation(s)
- Xin-He Lai
- Institute of Inflammation & Diseases, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China; Institute of Translational Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Long-Fei Zhao
- College of Life Sciences, Key Laboratory of Plant-Microbe Interactions of Henan, Shangqiu Normal University, Shangqiu, Henan, 476000, PR China
| | - Xiao-Ming Chen
- Institute of Inflammation & Diseases, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China; Institute of Translational Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China ; Department of Pediatric Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yi Ren
- Institute of Inflammation & Diseases, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China; Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL, USA
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Dong HT, Gangnonngiw W, Phiwsaiya K, Charoensapsri W, Nguyen VV, Nilsen P, Pradeep PJ, Withyachumnarnkul B, Senapin S, Rodkhum C. Duplex PCR assay and in situ hybridization for detection of Francisella spp. and Francisella noatunensis subsp. orientalis in red tilapia. DISEASES OF AQUATIC ORGANISMS 2016; 120:39-47. [PMID: 27304869 DOI: 10.3354/dao03021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Conventional isolation and identification based on phenotypic characteristics is challenging with the highly fastidious, intracellular bacterium Francisella noatunensis subsp. orientalis (Fno). Here, we developed a duplex PCR method for simultaneous detection of the Francisella genus and Fno in one PCR reaction and an in situ hybridization method for paraffin section based diagnosis of Fno. The PCR results showed genus- and species-specific bands (1140 and 203 bp) from Fno but only one genus-specific band (1140 bp) from F. noatunensis subsp. noatunensis. Sensitivity of the duplex PCR assay revealed a detection limit of 20 to 200 fg genomic DNA (~10 to 100 genome equivalents) depending on DNA template extraction methods. The newly developed duplex PCR assay could be used to detect Fno from clinically sick fish exhibiting signs of visceral granulomas and would also be able to detect Fno infection in naturally diseased fish without symptoms of francisellosis, indicating potential application for diagnosis of field samples. The in situ hybridization assay using Fno species-specific probe revealed positive signals in multiple organs including the spleen, liver, kidney, gills and intestine of infected fish.
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Affiliation(s)
- Ha T Dong
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
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Dissection of Francisella-Host Cell Interactions in Dictyostelium discoideum. Appl Environ Microbiol 2015; 82:1586-1598. [PMID: 26712555 DOI: 10.1128/aem.02950-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 12/22/2015] [Indexed: 12/31/2022] Open
Abstract
Francisella bacteria cause severe disease in both vertebrates and invertebrates and include one of the most infectious human pathogens. Mammalian cell lines have mainly been used to study the mechanisms by which Francisella manipulates its host to replicate within a large variety of hosts and cell types, including macrophages. Here, we describe the establishment of a genetically and biochemically tractable infection model: the amoeba Dictyostelium discoideum combined with the fish pathogen Francisella noatunensis subsp. noatunensis. Phagocytosed F. noatunensis subsp. noatunensis interacts with the endosomal pathway and escapes further phagosomal maturation by translocating into the host cell cytosol. F. noatunensis subsp. noatunensis lacking IglC, a known virulence determinant required for Francisella intracellular replication, follows the normal phagosomal maturation and does not grow in Dictyostelium. The attenuation of the F. noatunensis subsp. noatunensis ΔiglC mutant was confirmed in a zebrafish embryo model, where growth of F. noatunensis subsp. noatunensis ΔiglC was restricted. In Dictyostelium, F. noatunensis subsp. noatunensis interacts with the autophagic machinery. The intracellular bacteria colocalize with autophagic markers, and when autophagy is impaired (Dictyostelium Δatg1), F. noatunensis subsp. noatunensis accumulates within Dictyostelium cells. Altogether, the Dictyostelium-F. noatunensis subsp. noatunensis infection model recapitulates the course of infection described in other host systems. The genetic and biochemical tractability of the system allows new approaches to elucidate the dynamic interactions between pathogenic Francisella and its host organism.
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Brudal E, Lampe EO, Reubsaet L, Roos N, Hegna IK, Thrane IM, Koppang EO, Winther-Larsen HC. Vaccination with outer membrane vesicles from Francisella noatunensis reduces development of francisellosis in a zebrafish model. FISH & SHELLFISH IMMUNOLOGY 2015; 42:50-57. [PMID: 25449706 DOI: 10.1016/j.fsi.2014.10.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/17/2014] [Accepted: 10/17/2014] [Indexed: 06/04/2023]
Abstract
Infection of fish with the facultative intracellular bacterium Francisella noatunensis remains an unresolved problem for aquaculture industry worldwide as it is difficult to vaccinate against without using live attenuated vaccines. Outer membrane vesicles (OMVs) are biological structures shed by Gram-negative bacteria in response to various environmental stimuli. OMVs have successfully been used to vaccinate against both intracellular and extracellular pathogens, due to an ability to stimulate innate, cell-mediated and humoral immune responses. We show by using atomic force and electron microscopy that the fish pathogenic bacterium F. noatunensis subspecies noatunensis (F.n.n.) shed OMVs both in vitro into culture medium and in vivo in a zebrafish infection model. The main protein constituents of the OMV are IglC, PdpD and PdpA, all known Francisella virulence factors, in addition to the outer membrane protein FopA and the chaperonin GroEL, as analyzed by mass spectrometry. The vesicles, when used as a vaccine, reduced proliferation of the bacterium and protected zebrafish when subsequently challenged with a high dose of F.n.n. without causing adverse effects for the host. Also granulomatous responses were reduced in F.n.n.-challenged zebrafish after OMV vaccination. Taken together, the data support the possible use of OMVs as vaccines against francisellosis in fish.
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Affiliation(s)
- Espen Brudal
- Section for Microbiology, Immunology and Parasitology, Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, PO Box 8146 Dep, 0033 Oslo, Norway; Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway
| | - Elisabeth O Lampe
- Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway; Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway
| | - Léon Reubsaet
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway
| | - Norbert Roos
- Department of Biosciences, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway
| | - Ida K Hegna
- Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway; Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway
| | - Ida Marie Thrane
- Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway; Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway
| | - Erling O Koppang
- Section for Anatomy and Pathology, Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, PO Box 8146 Dep, 0033 Oslo, Norway
| | - Hanne C Winther-Larsen
- Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway; Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway.
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