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Kawahara M, Cody TT, Yanong RPE, Henderson E, Yazdi Z, Soto E. Francisella sciaenopsi sp. nov. isolated from diseased red drum Sciaenops ocellatus in Florida, USA. DISEASES OF AQUATIC ORGANISMS 2024; 159:79-89. [PMID: 39145474 DOI: 10.3354/dao03803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
Piscine francisellosis is one of the most important bacterial diseases affecting various fish species worldwide. Francisella orientalis, F. noatunensis, and F. salimarina (F. marina) have been reported as etiological agents of disease in fish. A Francisella sp. was isolated from several diseased red drum Sciaenops ocellatus experiencing morbidity in Florida, USA, in 2008. In this study, molecular and phenotypic characterization of the recovered isolate was conducted. Phenotypically, the isolate showed a biochemical reaction profile distinct from that of F. orientalis and F. salimarina. Although the 16S rRNA sequence of this isolate shared 99.61% identity to the type strain of F. philomiragia O#319LT, whole genome analysis (average nucleotide identity <95%; digital DNA-DNA hybridization <70%) and a multilocus sequence analysis of 8 concatenated housekeeping genes in comparison with other Francisella spp. indicated that this isolate was a novel Francisella species, more closely related to F. orientalis. Immersion, intracoelomic injection, and co-habitation challenges using a Nile tilapia Oreochromis niloticus fingerling model of infection were done to investigate virulence in a piscine model. Variably pigmented granulomas and pigmented macrophage aggregates were observed in the kidneys and spleens of the challenged fish, but no mortality was recorded during the 15 d challenge period, suggesting that this novel Francisella sp. might be an opportunistic pathogen of fish. Based on the phenotypic and genotypic differences from other Francisella spp. observed in this study, we propose the name Francisella sciaenopsi sp. nov. for this novel isolate.
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Affiliation(s)
- Miku Kawahara
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Theresa T Cody
- Fish and Wildlife Health, Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, St. Petersburg, Florida 33701, USA
| | - Roy P E Yanong
- Tropical Aquaculture Laboratory, Fisheries and Aquatic Sciences Program, School of Forest, Fisheries, and Geomatics Sciences, Institute of Food and Agricultural Sciences, University of Florida, Ruskin, Florida 33570, USA
| | - Eileen Henderson
- California Animal Health and Food Safety Lab, School of Veterinary Medicine, University of California-Davis, San Bernardino, CA 92408, USA
| | - Zeinab Yazdi
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Esteban Soto
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
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de Alexandre Sebastião F, Hansen JD, Soto E. Evaluation of Francisella orientalis ΔpdpA as a Live Attenuated Vaccine against Piscine Francisellosis in Nile Tilapia. JOURNAL OF AQUATIC ANIMAL HEALTH 2022; 34:134-139. [PMID: 35997232 DOI: 10.1002/aah.10166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
Francisella orientalis is an important bacterial pathogen of marine and freshwater fish with worldwide distribution. Fish francisellosis is a severe subacute to chronic granulomatous disease, with high mortalities and high infectivity rates in cultured and wild fish. To date, there is no approved vaccine for this disease. In this study, we evaluated the efficacy of a defined F. orientalis pathogenicity determinant protein A (pdpA) mutant (ΔpdpA) as a live attenuated immersion vaccine against subsequent immersion challenge with the wild-type organism. Immunized Nile tilapia Oreochromis niloticus were protected (45% relative percent survival) from the lethal challenges and presented significantly lower mortality than nonvaccinated and challenged treatments. Although serum IgM was significantly higher in immunized fish, similar bacterial loads were detected in vaccinated and nonvaccinated survivors. In conclusion, although the F. orientalis ΔpdpA is attenuated and effectively stimulated an adaptive immune response, the low relative percent survival and high bacterial persistence in survivors of immunized and challenged treatments indicates low suitability of ΔpdpA as a mucosal vaccine for tilapia under conditions used in this study.
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Affiliation(s)
- Fernanda de Alexandre Sebastião
- School of Veterinary Medicine, Department of Medicine and Epidemiology, University of California-Davis, Davis, California, 95616, USA
| | - John D Hansen
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, 98115, USA
| | - Esteban Soto
- School of Veterinary Medicine, Department of Medicine and Epidemiology, University of California-Davis, Davis, California, 95616, USA
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Hansen JD, Ray K, Chen PJ, Yun S, Elliott DG, Conway CM, Calcutt MJ, Purcell MK, Welch TJ, Bellah JP, Davis EM, Greer JB, Soto E. Disruption of the Francisella noatunensis subsp. orientalis pdpA Gene Results in Virulence Attenuation and Protection in Zebrafish. Infect Immun 2021; 89:e0022021. [PMID: 34424748 PMCID: PMC8519269 DOI: 10.1128/iai.00220-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/10/2021] [Indexed: 12/20/2022] Open
Abstract
Several Francisella spp., including Francisella noatunensis, are regarded as important emerging pathogens of wild and farmed fish. However, very few studies have investigated the virulence factors that allow these bacterial species to be pathogenic in fish. The Francisella pathogenicity island (FPI) is a well-described, gene-dense region encoding major virulence factors for the genus Francisella. pdpA is a member of the pathogenicity-determining protein genes carried by the FPI that are implicated in the ability of the mammalian pathogen Francisella tularensis to escape and replicate in infected host cells. Using a sacB suicide approach, we generated pdpA knockouts to address the role of PdpA as a virulence factor for F. noatunensis. Because polarity can be an issue in gene-dense regions, we generated two different marker-based mutants in opposing polarity (the F. noatunensis subsp. orientalis ΔpdpA1 and ΔpdpA2 strains). Both mutants were attenuated (P < 0.0001) in zebrafish challenges and displayed impaired intracellular replication (P < 0.05) and cytotoxicity (P < 0.05), all of which could be restored to wild-type (WT) levels by complementation for the ΔpdpA1 mutant. Importantly, differences were found for bacterial burden and induction of acute-phase and proinflammatory genes for the F. noatunensis subsp. orientalis ΔpdpA1 and ΔpdpA2 mutants compared to the WT during acute infection. In addition, neither mutant resulted in significant histopathological changes. Finally, immunization with the F. noatunensis subsp. orientalis ΔpdpA1 mutant led to protection (P < 0.012) against an acute 40% lethal dose (LD40) challenge with WT F. noatunensis in the zebrafish model of infection. Taken together, the results from this study further demonstrate physiological similarities within the genus Francisella relative to their phylogenetic relationships and the utility of zebrafish for addressing virulence factors for the genus.
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Affiliation(s)
- John D. Hansen
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, USA
| | - Karina Ray
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, USA
| | - Po-Jui Chen
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, USA
| | - Susan Yun
- Department of Medicine and Epidemiology, University of California—Davis, School of Veterinary Medicine, Davis, California, USA
| | - Diane G. Elliott
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, USA
| | - Carla M. Conway
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, USA
| | - Michael J. Calcutt
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, Missouri, USA
| | - Maureen K. Purcell
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, USA
| | - Timothy J. Welch
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, USA
| | - John P. Bellah
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, USA
| | - Ellie M. Davis
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, USA
| | - Justin B. Greer
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, USA
| | - Esteban Soto
- Department of Medicine and Epidemiology, University of California—Davis, School of Veterinary Medicine, Davis, California, USA
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Nguyen VV, Dong HT, Senapin S, Kayansamruaj P, Pirarat N, Rung-Ruangkijkrai T, Tiawsirisup S, Rodkhum C. Synergistic infection of Ichthyophthirius multifiliis and Francisella noatunensis subsp. orientalis in hybrid red tilapia (Oreochromis sp.). Microb Pathog 2020; 147:104369. [PMID: 32634614 DOI: 10.1016/j.micpath.2020.104369] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 06/29/2020] [Accepted: 06/29/2020] [Indexed: 11/28/2022]
Abstract
Francisella noatunensis subsp. orientalis (Fno) and Ichthyophthirius multifiliis (Ich) are deadly infectious pathogens in farmed tilapia, particularly during cold season when the water temperature drops to under 25 °C. We hypothesized that infection of the ectoparasite Ich might enhance susceptibility of hybrid red tilapia (Oreochromis sp.) to the facultative intracellular bacterium Fno. To prove the hypothesis, the experiment was designed as follows. Hybrid red tilapia naturally infected by Ich at 9 ± 6 theronts/fish gills and 4 ± 3 theronts/fish skin were distributed into 5 distinct groups exposed to different concentrations of Fno. In parallel, the same number of Ich-free tilapia were challenged to only Fno in the same manner. The results showed that cumulative mortality in the Fno single infection with 2.88 × 106 CFU mL-1 of water was 25 ± 7%, whereas 100% mortality was found in the coinfection treatment at dose of 1.93 × 105 CFU mL-1 of water. No mortality was observed in both control groups (Ich-infected and Ich-free fish). The coinfected fish revealed typical clinical signs and histopathological manifestations of francisellosis and ichthyophthiriasis. This study revealed synergistic effect of the Ich and Fno infection in hybrid red tilapia leading to the exacerbated mortality. Thus, farming management of fish to be free from the Ich ectoparasite might reduce risk of francisellosis and probably other bacterial diseases in farmed tilapia.
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Affiliation(s)
- Vuong Viet Nguyen
- Fish Infectious Diseases Research Unit (FID RU), Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand; Research Institute of Aquaculture No. 1 (RIA1), 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), Pathum Thani, Thailand; Fish Health Platform, Center of Excellence for Shrimp Molecular Biology and Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | | | - Nopadon Pirarat
- Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Tilladit Rung-Ruangkijkrai
- Department of Veterinary Anatomy, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Sonthaya Tiawsirisup
- The Veterinary Parasitology Unit, Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Channarong Rodkhum
- Fish Infectious Diseases Research Unit (FID RU), Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
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Pulpipat T, Maekawa S, Wang PC, Chen SC. Immune Responses and Protective Efficacy of a Formalin-Killed Francisella Noatunensis Subsp. Orientalis Vaccine Evaluated through Intraperitoneal and Immersion Challenge Methods in Oreochromis Niloticus. Vaccines (Basel) 2020; 8:vaccines8020163. [PMID: 32260212 PMCID: PMC7348880 DOI: 10.3390/vaccines8020163] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 12/25/2022] Open
Abstract
Francisella noatunensis subsp. orientalis (Fno), an intracellular bacterium, causes systemic granulomatous diseases, resulting in high mortality and huge economic losses in Taiwanese tilapia farming. In this study, we tested the efficacy of a formalin-killed Fno vaccine in cultured tilapia. Fno was isolated from diseased tilapia, inactivated with formalin, and mixed with the mineral oil base adjuvant (MontanideTM ISA 763 AVG). A total of 300 tilapia were divided into two groups. The experimental group was intraperitoneally injected with 0.1 mL of vaccine, which was substituted with phosphate-buffered saline (PBS) in the control group. A booster was administered at 2 weeks post-immunization. Tilapia were challenged at 6 weeks post primary immunization by intraperitoneal (IP) injection and immersion methods. Mortality was recorded at 21 and 60 days. The results revealed that the vaccine induced a greater antibody titer and led to 71% and 76% of relative percent survival (RPS) after the IP and immersion challenge. The transcripts of proinflammatory cytokines and immune-related genes, including interleukin-1β (IL-1β), tumor necrosis factor alpha (TNFα), C-X-C motif chemokine ligand 8 (CXCL8), and interleukin-17C (IL-17C), were significantly upregulated after vaccination. Additionally, vaccinated fish had lower bacterial loads in the blood and lower granuloma intensities in the kidney, spleen, liver, and gill than control fish. The results in this study demonstrate that the inactivated Fno vaccine could be an essential resource in Taiwanese tilapia farming.
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Affiliation(s)
- Theeraporn Pulpipat
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan; (T.P.); (S.M.); (P.-C.W.)
| | - Shun Maekawa
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan; (T.P.); (S.M.); (P.-C.W.)
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Research Center for Fish Vaccine and Diseases, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
| | - Pei-Chi Wang
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan; (T.P.); (S.M.); (P.-C.W.)
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Research Center for Fish Vaccine and Diseases, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Southern Taiwan Fish Diseases Research Center, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
| | - Shih-Chu Chen
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan; (T.P.); (S.M.); (P.-C.W.)
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Research Center for Fish Vaccine and Diseases, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Southern Taiwan Fish Diseases Research Center, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Research Center for Animal Biologics, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Correspondence: ; Tel.: +886-8-770-3202 (ext. 5076 or 5095)
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Larva of greater wax moth Galleria mellonella is a suitable alternative host for the fish pathogen Francisella noatunensis subsp. orientalis. BMC Microbiol 2020; 20:8. [PMID: 31918661 PMCID: PMC6953311 DOI: 10.1186/s12866-020-1695-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 12/31/2019] [Indexed: 12/26/2022] Open
Abstract
Background Francisella noatunensis subsp. orientalis (Fno) is the etiological agent of francisellosis in cultured warm water fish, such as tilapia. Antibiotics are administered to treat the disease but a better understanding of Fno infection biology will inform improved treatment and prevention measures. However, studies with native hosts are costly and considerable benefits would derive from access to a practical alternative host. Here, larvae of Galleria mellonella were assessed for suitability to study Fno virulence. Results Larvae were killed by Fno in a dose-dependent manner but the insects could be rescued from lethal doses of bacteria by antibiotic therapy. Infection progression was assessed by histopathology (haematoxylin and eosin staining, Gram Twort and immunohistochemistry) and enumeration of bacteria recovered from the larval haemolymph on selective agar. Fno was phagocytosed and could survive intracellularly, which is consistent with observations in fish. Virulence of five Fno isolates showed strong agreement between G. mellonella and red Nile tilapia hosts. Conclusions This study shows that an alternative host, G. mellonella, can be applied to understand Fno infections, which will assist efforts to identify solutions to piscine francisellosis thus securing the livelihoods of tilapia farmers worldwide and ensuring the production of this important food source.
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López-Crespo RA, Martínez-Chavarría LC, Lugo-García AT, Romero-Romero LP, García-Márquez LJ, Reyes-Matute A. Outbreak of francisellosis (Francisella noatunensis subsp. orientalis) in cultured neon jewel cichlids Hemichromis bimaculatus from Morelos, Mexico. DISEASES OF AQUATIC ORGANISMS 2019; 137:125-130. [PMID: 31854330 DOI: 10.3354/dao03429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Francisellosis is a disease caused by different species of the bacterial genus Francisella and has been diagnosed in a wide variety of animals, including fish. Francisellosis in fish is characterized by the development of non-specific clinical signs as well as the presence of numerous granulomas in several organs (mainly spleen and kidney). Ten neon jewel cichlids Hemichromis bimaculatus were submitted for diagnosis from a farm located in Morelos, Mexico. Gross examination, wet preparations, cytology, histopathology and PCR were performed. Affected fish showed lethargy, erratic swimming, imbalance and gasping. At the post mortem examination, multiple granulomas were observed in the kidney and spleen. Microscopically, granulomatous inflammation was observed in several organs. Species-specific PCR assay using DNA from the affected tissues of H. bimaculatus as a template demonstrated the presence of F. noatunensis subsp. orientalis (Fno) by amplifying a hypothetical protein gene of the Fno species. The end diagnosis of francisellosis is important for Mexican ornamental aquaculture, since it is necessary to implement measures for treatment, prevention, control and diagnosis. This is the first report of francisellosis in the neon jewel cichlid.
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Affiliation(s)
- Rubén A López-Crespo
- Departamento de Patología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, CP 04510, Ciudad de México, México
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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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Pereira FL, Tavares GC, de Carvalho AF, Rosa JCC, Rezende CP, Leal CAG, Figueiredo HCP. Effects of temperature changes in the transcriptional profile of the emerging fish pathogen Francisella noatunensis subsp. orientalis. Microb Pathog 2019; 133:103548. [PMID: 31112771 DOI: 10.1016/j.micpath.2019.103548] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 01/05/2023]
Abstract
One of the major challenges in Nile tilapia (Oreochromis niloticus L.) farming is the occurrence of bacterial infections, and the Francisella noatunensis subsp. orientalis (FNO) is an important pathogen that has emerged in last decades. Francisellosis outbreaks have been reported in the literature as occurring seasonally when water temperature is below 24 °C. The aim of this study was to quantify the median lethal doses (LD50) of FNO in experimental challenges at 28 °C and 22 °C, and to investigate the impact of temperature changes in whole genome expression using microarray technology. The LD50 for Nile tilapia at 28 °C was ∼105.7, whereas at 22 °C, the LD50 was ∼102.2, showing that the decrease in temperature enhanced disease outcome. Out of 1917 genes screened, a total of 31 and 19 genes were down- and up-regulated at 22 °C, respectively. These genes were grouped by orthology into functional categories of: amino acid, inorganic ion, and carbohydrate transport and metabolism; transcription; and posttranslational modification, protein turnover, and chaperones. Expression of genes related to metabolism, oxidative stress, and thermal shock were regulated by temperature changes, reflecting an ability of FNO to adapt to the environment. Expression of virulence genes usually required for the Francisella genus was not changed between tested temperatures, including that of genes located on the Francisella Pathogenicity Island.
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Affiliation(s)
- Felipe Luiz Pereira
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Guilherme Campos Tavares
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Alex Fiorini de Carvalho
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Júlio César Camara Rosa
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Cristiana Perdigão Rezende
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Carlos Augusto Gomes Leal
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Henrique César Pereira Figueiredo
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil. http://www.vet.ufmg.br/
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Pulpipat T, Lin KH, Chen YH, Wang PC, Chen SC. Molecular characterization and pathogenicity of Francisella noatunensis subsp. orientalis isolated from cultured tilapia (Oreochromis sp.) in Taiwan. JOURNAL OF FISH DISEASES 2019; 42:643-655. [PMID: 30715744 DOI: 10.1111/jfd.12964] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/28/2018] [Accepted: 12/31/2018] [Indexed: 06/09/2023]
Abstract
Francisella noatunensis subsp. orientalis is a causative agent of systemic granulomatous disease in tilapia. The present study was designed to understand the genetic and phenotypic diversities among Taiwanese Fno isolates obtained from tilapia (n = 17) and green Texas cichlid (Herichthys cyanoguttatus) (n = 1). The enzymatic profiles of the isolates were studied using the API ZYM system. Phylogenetic tree analysis of the 16S rRNA and housekeeping gene and pulsed-field gel electrophoresis (PFGE) were carried out to determine the genotypic characters of all isolates. The phylogenetic tree showed similarity of 99%-100% nucleotide sequences of 16S rRNA and housekeeping genes compared to the Fno references genes from GenBank database. Comparatively, the results revealed an identical profile of enzymatic and PFGE pattern which was distincted from that of F. philomiragia. To understand the pathogenicity, the isolates were intraperitoneal injected to tilapia the gross lesions were observed concomitant with natural outbreak. Median lethal dose upon Nile tilapia and red tilapia were 9.06 × 103 CFU/fish and 2.08 × 102 CFU/fish, respectively. Thus, our data provide understanding the epidemiology of Taiwanese Fno isolates, and help in development of future control and prevention.
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Affiliation(s)
- Theeraporn Pulpipat
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Kuo-Hua Lin
- Animal Protection Office, Taoyuan City, Taiwan
| | | | - Pei-Chi Wang
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Southern Taiwan Fish Diseases Research Center, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Shih-Chu Chen
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Southern Taiwan Fish Diseases Research Center, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Research Center for Animal Biologics, National Pingtung University of Science and Technology, Pingtung, Taiwan
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Shahin K, Thompson KD, Inglis NF, Mclean K, Ramirez-Paredes JG, Monaghan SJ, Hoare R, Fontaine M, Metselaar M, Adams A. Characterization of the outer membrane proteome of Francisella noatunensis subsp. orientalis. J Appl Microbiol 2018; 125:686-699. [PMID: 29777634 DOI: 10.1111/jam.13918] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 05/03/2018] [Accepted: 05/11/2018] [Indexed: 11/28/2022]
Abstract
AIMS The aims of the current study were to characterize the outer membrane proteins (OMPs) of Francisella noatunensis subsp. orientalis (Fno) STIR-GUS-F2f7, and identify proteins recognized by sera from tilapia, Oreochromis niloticus, (L) that survived experimental challenge with Fno. METHODS AND RESULTS The composition of the OMPs of a virulent strain of Fno (STIR-GUS-F2f7), isolated from diseased red Nile tilapia in the United Kingdom, was examined. The sarcosine-insoluble OMPs fraction was screened with tilapia hyperimmune sera by western blot analysis following separation of the proteins by 1D SDS-PAGE. Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was used to identify the various proteins present in the OMP profile. Two hundred and thirty-nine proteins were identified, of which 44 were found in the immunogenic band recognized by the tilapia hyperimmune serum. In silico analysis was performed to predict the function and location of the OMPs identified by MS. CONCLUSIONS Using a powerful proteomic-based approach in conjugation with western immunoblotting, proteins comprising the outer membrane fraction of Fno STIR-GUS-F2f7 were identified, catalogued and screened for immune recognition by tilapia sera. SIGNIFICANCE AND IMPACT OF THE STUDY The current study is the first report on the characterization of Fno-OMPs. The findings here provide preliminary data on bacterial surface proteins that exist in direct contact with the host's immune defences during infection and offer an insight into the pathogenesis of Fno.
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Affiliation(s)
- K Shahin
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, Scotland, UK.,Aquatic Animals Diseases Lab, Aquaculture Division, National Institute of Oceanography and Fisheries, Suez, Egypt
| | - K D Thompson
- Moredun Research Institute, Pentlands Science Park, Penicuik, Midlothian, UK
| | - N F Inglis
- Moredun Research Institute, Pentlands Science Park, Penicuik, Midlothian, UK
| | - K Mclean
- Moredun Research Institute, Pentlands Science Park, Penicuik, Midlothian, UK
| | - J G Ramirez-Paredes
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, Scotland, UK
| | - S J Monaghan
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, Scotland, UK
| | - R Hoare
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, Scotland, UK
| | - M Fontaine
- Benchmark Animal Health, Bush House, Edinburgh Technopole, Edinburgh, Midlothian, UK
| | - M Metselaar
- Benchmark Animal Health, Bush House, Edinburgh Technopole, Edinburgh, Midlothian, UK
| | - A Adams
- Faculty of Natural Sciences, Institute of Aquaculture, University of Stirling, Stirling, Scotland, UK
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Brenz Y, Winther-Larsen HC, Hagedorn M. Expanding Francisella models: Pairing up the soil amoeba Dictyostelium with aquatic Francisella. Int J Med Microbiol 2017; 308:32-40. [PMID: 28843671 DOI: 10.1016/j.ijmm.2017.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/31/2017] [Accepted: 08/04/2017] [Indexed: 12/19/2022] Open
Abstract
The bacterial genus Francisella comprises highly pathogenic species that infect mammals, arthropods, fish and protists. Understanding virulence and host defense mechanisms of Francisella infection relies on multiple animal and cellular model systems. In this review, we want to summarize the most commonly used Francisella host model platforms and highlight novel, alternative model systems using aquatic Francisella species. Established mouse and macrophage models contributed extensively to our understanding of Francisella infection. However, murine and human cells display significant differences in their response to Francisella infection. The zebrafish and the amoeba Dictyostelium are well-established model systems for host-pathogen interactions and open up opportunities to investigate bacterial virulence and host defense. Comparisons between model systems using human and fish pathogenic Francisella species revealed shared virulence strategies and pathology between them. Hence, zebrafish and Dictyostelium might complement current model systems to find new vaccine candidates and contribute to our understanding of Francisella infection.
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Affiliation(s)
- Yannick Brenz
- Department of Parasitology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany.
| | - Hanne C Winther-Larsen
- Centre for Integrative Microbial Evolution (CIME) and Department of Pharmaceutical Biosciences, University of Oslo, Sem Sælands vei 3, 0371 Oslo, Norway.
| | - Monica Hagedorn
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany.
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13
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Soto E, Yun S, Lewis J, Kearney MT, Hansen J. Interaction of Francisella noatunensis subsp. orientalis with Oreochromis mossambicus bulbus arteriosus cell line. Microb Pathog 2017; 105:326-333. [PMID: 28286149 DOI: 10.1016/j.micpath.2017.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/25/2017] [Accepted: 03/06/2017] [Indexed: 01/12/2023]
Abstract
Francisella noatunensis subsp. orientalis (Fno) (syn. F. asiatica) is an emergent warmwater fish pathogen and the causative agent of piscine francisellosis. Although Fno causes septicemia and can live extracellularly in infected tilapia (Oreochromis spp.), the early interaction of Fno with vasculature endothelium is unknown. In the present study, we examined the interaction of wild-type Fno (WT) and two Fno knockout [intracellular growth loci C (ΔiglC) and pathogenicity determinant protein A (ΔpdpA)] strains with the endothelial O. mossambicus bulbus arteriosus cell line (TmB) at 25 °C and 30 °C. Similar amounts of WT, ΔiglC, and ΔpdpA attached and were detected intracellularly after 5 h of incubation at both temperatures; however temperature affected attachment and uptake. While significantly greater amounts of Fno (WT, ΔiglC, and ΔpdpA) were detected intracellularly when TmB cells were incubated at 30 °C, bacteria attached to TmBs at greater levels at 25 °C. Only WT Fno was able to replicate intracellularly at 25 °C, which resulted in Fno mediated cytotoxicity and apoptosis at 24 and 72 h post-infection. WT Fno incubated at 30 °C as well as ΔiglC, and ΔpdpA incubated at 25 °C and 30 °C were all defective for survival, replication, and the ability to cause cytotoxicity in TmB. Taken together, these results demonstrate that temperature plays a vital role for Fno intracellular survival, persistence and cytotoxicity.
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Affiliation(s)
- Esteban Soto
- University of California-Davis, Department of Medicine and Epidemiology, School of Veterinary Medicine, Davis, CA 95616, USA.
| | - Susan Yun
- University of California-Davis, Department of Medicine and Epidemiology, School of Veterinary Medicine, Davis, CA 95616, USA
| | - Jainee Lewis
- University of California-Davis, Department of Medicine and Epidemiology, School of Veterinary Medicine, Davis, CA 95616, USA
| | - Michael T Kearney
- Louisiana State University, Department of Pathobiological Sciences, School of Veterinary Medicine, Baton Rouge, LA 70803, USA
| | - John Hansen
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA 98115, USA
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14
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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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15
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Soto E, Zayas M, Tobar J, Illanes O, Yount S, Francis S, Dennis M. Laboratory-controlled Challenges of Nile Tilapia (Oreochromis niloticus) with Streptococcus agalactiae: Comparisons between Immersion, Oral, Intracoelomic and Intramuscular Routes of Infection. J Comp Pathol 2016; 155:339-345. [DOI: 10.1016/j.jcpa.2016.09.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/07/2016] [Accepted: 09/29/2016] [Indexed: 10/20/2022]
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Lewisch E, Menanteau-Ledouble S, Tichy A, El-Matbouli M. Susceptibility of common carp and sunfish to a strain of Francisella noatunensis subsp. orientalis in a challenge experiment. DISEASES OF AQUATIC ORGANISMS 2016; 121:161-166. [PMID: 27667813 DOI: 10.3354/dao03044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Francisellosis, an emerging disease in many fish species, can cause high mortality in affected populations. Here we investigated the susceptibility of common carp Cyprinus carpio and sunfish Lepomis gibbosus to Francisella noatunensis subsp. orientalis (Fno), and possible transmission of the bacteria between the 2 fish species. In a challenge experiment, 3 groups of each species were injected intraperitoneally (IP) with 3 different doses of an Fno strain no. 9449 of the Norwegian Veterinary Institute, recovered from naturally infected ornamental Malawi cichlids. Infected carp were cohabitated with sunfish and vice versa. Control groups were injected with 0.9M phosphate-buffered saline and cohabitated accordingly. Fish were sampled at different time points. Mortality of challenged sunfish was observed during the first 96 h and reached 56.1%. In the control sunfish, 4 of 16 fish (25%) died within 48 h. In carp, no mortalities or clinical signs were observed during the experiment. General clinical and patho-anatomical disease signs of affected sunfish were observed. We detected granulomas in 2 cohabitated sunfish and 1 challenged carp, but could not re-isolate Fno from these fish. Fno was successfully cultured from 6 sunfish and 3 carp specimens until 35 d post injection. PCR of spleen and kidney with 16S rDNA Francisella-like bacterium primers 180f and 485r yielded amplicons in 68.3% of challenged sunfish and only 12.2% of challenged carp. We demonstrated that sunfish were susceptible to Fno infection while the carp were not. Horizontal transmission of the agent between the 2 fish species could not be demonstrated.
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Affiliation(s)
- E Lewisch
- Clinical Division of Fish Medicine, University of Veterinary Medicine, 1210 Vienna, Austria
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17
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Ortega C, Mancera G, Enríquez R, Vargas A, Martínez S, Fajardo R, Avendaño-Herrera R, Navarrete MJ, Romero A. First identification of Francisella noatunensis subsp. orientalis causing mortality in Mexican tilapia Oreochromis spp. DISEASES OF AQUATIC ORGANISMS 2016; 120:205-215. [PMID: 27503916 DOI: 10.3354/dao02999] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Francisellosis, an emerging disease in tilapia Oreochromis spp., is caused by the facultative, intracellular bacterium Francisella noatunensis subsp. orientalis, which is present in various countries where tilapia farming is commercially important. We confirmed the presence of francisellosis in Mexican tilapia cultures in association with an outbreak during the second semester of 2012. Broodstock fish presented a mortality rate of approximately 40%, and disease was characterized by histologically classified granulomas, or whitish nodules, in different organs, mainly the spleen and kidney. Through DNA obtained from infected tissue and pure cultures in a cysteine heart medium supplemented with hemoglobin, F. noatunensis subsp. orientalis was initially confirmed through the amplification and analysis of the 16S rRNA gene and the internal transcribed spacer region. Phylogenetic analysis of these genes demonstrated close similarity with previously reported F. noatunensis subsp. orientalis sequences obtained from infected tilapia from various countries. The identification of this subspecies as the causative agent of the outbreak was confirmed using the iglC gene as a target sequence, which showed 99.5% identity to 2 F. noatunensis subsp. orientalis strains (Ethime-1 and Toba04). These findings represent the first documented occurrence of francisellosis in Mexican tilapia cultures, which highlights the importance of establishing preventative measures to minimize the spread of this disease within the Mexican aquaculture industry.
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Affiliation(s)
- Cesar Ortega
- Centro de Investigación y Estudios Avanzados en Salud Animal (CIESA), Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma del Estado de México, Carretera Toluca-Atlacomulco Km. 15.5, Toluca 50200, Mexico
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18
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Soto E, Halliday-Simmonds I, Francis S, Kearney MT, Hansen JD. Biofilm formation of Francisella noatunensis subsp. orientalis. Vet Microbiol 2015; 181:313-7. [PMID: 26507830 DOI: 10.1016/j.vetmic.2015.10.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/29/2015] [Accepted: 10/08/2015] [Indexed: 11/25/2022]
Abstract
Francisella noatunensis subsp. orientalis (Fno) is an emergent fish pathogen in both marine and fresh water environments. The bacterium is suspected to persist in the environment even without the presence of a suitable fish host. In the present study, the influence of different abiotic factors such as salinity and temperature were used to study the biofilm formation of different isolates of Fno including intracellular growth loci C (iglC) and pathogenicity determinant protein A (pdpA) knockout strains. Finally, we compared the susceptibility of planktonic and biofilm to three disinfectants used in the aquaculture and ornamental fish industry, namely Virkon(®), bleach and hydrogen peroxide. The data indicates that Fno is capable of producing biofilms within 24 h where both salinity as well as temperature plays a role in the growth and biofilm formation of Fno. Mutations in the iglC or pdpA, both known virulence factors, do not appear to affect the capacity of Fno to produce biofilms, and the minimum inhibitory concentration, and minimum biocidal concentration for the three disinfectants were lower than the minimum biofilm eradication concentration values. This information needs to be taken into account if trying to eradicate the pathogen from aquaculture facilities or aquariums.
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Affiliation(s)
- Esteban Soto
- Department of Medicine and Epidemiology, University of California-Davis, School of Veterinary Medicine, Davis, CA 95616, USA; Department of Biomedical Sciences, Ross University School of Veterinary Medicine, P.O. Box 334, Basseterre, St. Kitts, West Indies.
| | - Iona Halliday-Simmonds
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, P.O. Box 334, Basseterre, St. Kitts, West Indies
| | - Stewart Francis
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, P.O. Box 334, Basseterre, St. Kitts, West Indies
| | - Michael T Kearney
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - John D Hansen
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA 98115, USA
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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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Soto E, Brown N, Gardenfors ZO, Yount S, Revan F, Francis S, Kearney MT, Camus A. Effect of size and temperature at vaccination on immunization and protection conferred by a live attenuated Francisella noatunensis immersion vaccine in red hybrid tilapia. FISH & SHELLFISH IMMUNOLOGY 2014; 41:593-599. [PMID: 25462454 DOI: 10.1016/j.fsi.2014.10.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 10/07/2014] [Accepted: 10/07/2014] [Indexed: 06/04/2023]
Abstract
Francisella noatunensis subsp. orientalis (Fno) is a pleomorphic, facultative intracellular, Gram-negative, emerging bacterial pathogen of marine and fresh water fish with worldwide distribution. In this study, the efficacy of an attenuated Fno intracellular growth locus C (iglC) mutant was evaluated for use as a live immersion vaccine, when administered to hybrid tilapia at two different stages of growth (5 g fry and 10 g fingerlings) and at two temperatures (25 °C and 30 °C). To determine vaccine efficacy, mortality, days to first death, and Fno genome equivalents (GE) in the spleens of survivors, as well as serum and mucus antibody levels, were evaluated after 30 d in fish challenged with a wild type virulent strain. Both size and temperature at vaccination played an important role in immunization and protection. Fry vaccinated at 25 °C were not protected when compared to non-vaccinated fry at 25 °C (p = 0.870). In contrast, 5 g fry vaccinated at 30 °C were significantly protected compared to non-vaccinated fry at 30 °C (p = 0.038). Although lower mortalities occurred, 10 g fingerlings vaccinated at 25 °C were not protected, compared to non-vaccinated fingerlings at 25 °C (p = 0.328), while, 10 g fingerlings vaccinated at 30 °C were significantly protected, compared to non-vaccinated fingerlings at 30 °C (p = 0.038). Additionally, overall mortality of 5 g fish was significantly higher than in 10 g fish. Mortality was also significantly higher in fish subjected to a 30 to 25 °C temperature change one week prior to challenge, than in fish maintained at the same temperature during vaccination and challenge. This information demonstrates that both temperature and size at vaccination are important factors when implementing immunization prophylaxis in cultured tilapia.
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Affiliation(s)
- Esteban Soto
- Center for Conservation Medicine and Ecosystem Health, School of Veterinary Medicine, Ross University, Main Island Road, West Farm, Saint Kitts and Nevis.
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21
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Establishment of three Francisella infections in zebrafish embryos at different temperatures. Infect Immun 2014; 82:2180-94. [PMID: 24614659 DOI: 10.1128/iai.00077-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Francisella spp. are facultative intracellular pathogens identified in increasingly diverse hosts, including mammals. F. noatunensis subsp. orientalis and F. noatunensis subsp. noatunensis infect fish inhabiting warm and cold waters, respectively, while F. tularensis subsp. novicida is highly infectious for mice and has been widely used as a model for the human pathogen F. tularensis. Here, we established zebrafish embryo infection models of fluorescently labeled F. noatunensis subsp. noatunensis, F. noatunensis subsp. orientalis, and F. tularensis subsp. novicida at 22, 28, and 32°C, respectively. All infections led to significant bacterial growth, as shown by reverse transcription-quantitative PCR (RT-qPCR), and to a robust proinflammatory immune response, dominated by increased transcription of tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β). F. noatunensis subsp. orientalis was the most virulent, F. noatunensis subsp. noatunensis caused chronic infection, and F. tularensis subsp. novicida showed moderate virulence and led to formation of relatively small granuloma-like structures. The use of transgenic zebrafish strains with enhanced green fluorescent protein (EGFP)-labeled immune cells revealed their detailed interactions with Francisella species. All three strains entered preferentially into macrophages, which eventually assembled into granuloma-like structures. Entry into neutrophils was also observed, though the efficiency of this event depended on the route of infection. The results demonstrate the usefulness of the zebrafish embryo model for studying infections caused by different Francisella species at a wide range of temperatures and highlight their interactions with immune cells.
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Francisella noatunensis subsp. orientalis pathogenesis analyzed by experimental immersion challenge in Nile tilapia, Oreochromis niloticus (L.). Vet Microbiol 2013; 164:77-84. [DOI: 10.1016/j.vetmic.2013.01.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 01/18/2013] [Accepted: 01/22/2013] [Indexed: 10/27/2022]
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Soto E, Kidd S, Gaunt PS, Endris R. Efficacy of florfenicol for control of mortality associated with Francisella noatunensis subsp. orientalis in Nile tilapia, Oreochromis niloticus (L.). JOURNAL OF FISH DISEASES 2013; 36:411-418. [PMID: 23134104 DOI: 10.1111/j.1365-2761.2012.01425.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 06/21/2012] [Accepted: 06/29/2012] [Indexed: 06/01/2023]
Abstract
Francisella noatunensis subsp. orientalis (Fno) (syn. F. asiatica) is an emergent Gram-negative facultative intracellular bacterium. Although it is considered one of the most pathogenic bacteria in fish, there are no commercially available treatments or vaccines. The objective of this project was to determine the most efficacious concentration of florfenicol (FFC) [10, 15 or 20 mg FFC kg(-1) body weight (bw) per days for 10 days] administered in feed to control experimentally induced infections of Fno in Nile tilapia, Oreochromis niloticus (L.), reared in a recirculating aquaculture system. The cumulative mortality of fish that received 0, 10, 15 or 20 mg FFC kg(-1) bw per day was 60, 37, 14 and 16%, respectively. Francisella noatunensis subsp. orientalis genome equivalents were detected in water from all challenged groups with slight reduction in the concentration in the florfenicol-treated groups 4 days after treatment. The mean LOG of CFU Fno mg(-1) spleen was 3-5 and was present in all challenged groups at necropsy 11 days after treatment (21 days after challenge). Results show that florfenicol administered at doses of 15 and 20 mg FFC kg(-1) bw per days for 10 days significantly reduced mortality associated with francisellosis in Nile tilapia.
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Affiliation(s)
- E Soto
- Department of Pathobiology, School of Veterinary Medicine, Ross University, Basseterre, St. Kitts, West Indies.
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Brudal E, Winther-Larsen HC, Colquhoun DJ, Duodu S. Evaluation of reference genes for reverse transcription quantitative PCR analyses of fish-pathogenic Francisella strains exposed to different growth conditions. BMC Res Notes 2013; 6:76. [PMID: 23452832 PMCID: PMC3599356 DOI: 10.1186/1756-0500-6-76] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 02/27/2013] [Indexed: 12/20/2022] Open
Abstract
Background Reverse transcription quantitative PCR has become a powerful technique to monitor mRNA transcription in response to different environmental conditions in many bacterial species. However, correct evaluation of data requires accurate and reliable use of reference genes whose transcription does not change during the course of the experiment. In the present study exposure to different growth conditions was used to validate the transcription stability of eight reference gene candidates in three strains from two subspecies of Francisella noatunensis, a pathogen causing disease in both warm and cold water fish species. Results Relative transcription levels for genes encoding DNA gyrase (gyrA), RNA polymerase beta subunit (rpoB), DNA polymerase I (polA), cell division protein (ftsZ), outer membrane protein (fopA), riboflavin biosynthesis protein (ribC), 16S ribosomal RNA (16S rRNA) and DNA helicases (uvrD) were quantified under exponential, stationary and iron-restricted growth conditions. The suitability of selected reference genes for reliable interpretation of gene expression data was tested using the virulence-associated intracellular growth locus subunit C (iglC) gene. Conclusion Although the transcription stability of the reference genes was slightly different in the three strains studied, fopA, ftsZ and polA proved to be the most stable and suitable for normalization of gene transcription in Francisella noatunensis ssp.
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Affiliation(s)
- Espen Brudal
- Section for Microbiology, Immunology and Parasitology, Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, PO Box 8146 Dep, Oslo 0033, Norway
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Duodu S, Larsson P, Sjödin A, Soto E, Forsman M, Colquhoun DJ. Real-time PCR assays targeting unique DNA sequences of fish-pathogenic Francisella noatunensis subspecies noatunensis and orientalis. DISEASES OF AQUATIC ORGANISMS 2012; 101:225-234. [PMID: 23324419 DOI: 10.3354/dao02514] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Specific identification and differentiation of the 2 subspecies of the fish pathogen Francisella noatunensis, namely, F. noatunensis subsp. noatunensis and F. noatunensis subsp. orientalis, remains a major diagnostic challenge. Following whole-genome sequencing and analysis of representatives of all major subclades of the genus Francisella, specific genomic regions were identified for each of the subspecies of this fish pathogen. Two specific real-time quantitative PCR assays, directed at hypothetical genes within these regions were developed. Specificity was confirmed by lack of signal and cross-reactivity with the closest relative, F. philomiragia, and other common bacterial fish pathogens. Both assays, used either as monoplex or multiplex, have a limit of detection of 10 genome equivalents. The quantitative sensitivity of the assays was not affected by the presence of kidney tissues or DNA from Atlantic cod Gadus morhua or tilapia Oreochromis sp.
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Affiliation(s)
- Samuel Duodu
- Section for Bacteriology, Norwegian Veterinary Institute, PO Box 750, Sentrum, 0106 Oslo, Norway.
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26
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Soto E, Abrams SB, Revan F. Effects of temperature and salt concentration on Francisella noatunensis subsp. orientalis infections in Nile tilapia Oreochromis niloticus. DISEASES OF AQUATIC ORGANISMS 2012; 101:217-223. [PMID: 23324418 DOI: 10.3354/dao02533] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Little is known about the environmental conditions that allow Francisella noatunensis subsp. orientalis, a worldwide emergent bacterial fish pathogen, to colonize and infect wild and cultured fish. We evaluated the effect of temperature and salinity on the infectivity of F. noatunensis subsp. orientalis in Nile tilapia Oreochromis niloticus (L). Immersion challenges of tilapia with F. noatunensis subsp. orientalis at water temperatures of 25 and 30°C in both sea and fresh water were conducted for 14 d. Morbidity and mortality were recorded daily, and at the completion of the study, a quantitative assessment of the splenic bacterial burden was performed in surviving fish. Fish maintained at 25°C developed francisellosis and had considerably higher mortality and splenic bacterial concentrations compared to control fish and fish maintained at 30°C. Moreover, increasing the water temperature from 25 to 30°C prevented the development of clinical signs and mortality in Francisella-challenged fish. In conclusion, temperature significantly influenced the development of francisellosis in tilapia, whereas salinity had no effect. Our findings may be useful in the establishment of improved prophylactic practices and in the management of outbreaks of francisellosis in the aquaculture industry.
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Affiliation(s)
- Esteban Soto
- Department of Pathobiology, School of Veterinary Medicine, Ross University, Basseterre, St. Kitts, West Indies.
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Soto E, Griffin M, Arauz M, Riofrio A, Martinez A, Cabrejos ME. Edwardsiella ictaluri as the causative agent of mortality in cultured Nile tilapia. JOURNAL OF AQUATIC ANIMAL HEALTH 2012; 24:81-90. [PMID: 22838078 DOI: 10.1080/08997659.2012.675931] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Edwardsiella ictaluri was consistently isolated from the spleens, livers, and head kidneys of diseased Nile tilapia Oreochromis niloticus from a farm experiencing mortality events in several culture ponds. We describe the first published outbreak of E. ictaluri-induced edwardsiellosis in Nile tilapia. Pure cultures of the isolated bacteria were characterized both biochemically and molecularly. Biochemical analysis was performed using the API-20E and RapID One systems, and antimicrobial susceptibility was determined by the broth microdilution method. Molecular analysis involved sequencing of the 16S rRNA gene, species-specific real-time polymerase chain reaction (PCR), and PCR-mediated genomic fingerprinting (rep-PCR). Pairwise sequence analysis of the 16S rRNA gene identified the case isolates to be a 100% match to E. ictaluri cultured from channel catfish in the southeastern United States. However, rep-PCR analysis identified the case isolates to be genetically different from representative strains isolated from disease outbreaks in cultured channel catfish in Mississippi. Infectivity challenges (intraperitoneal injection and immersion) demonstrated that a representative E. ictaluri strain isolated from tilapia was pathogenic to naive tilapia, reproducing clinical signs and mortality, thereby establishing Koch's postulates.
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Affiliation(s)
- Esteban Soto
- Department of Pathobiology, School of Veterinary Medicine, Ross University, Basseterre, St. Kitts, West Indies.
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28
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Soto E, Revan F. Culturability and persistence of Francisella noatunensis subsp. orientalis (syn. Francisella asiatica) in sea- and freshwater microcosms. MICROBIAL ECOLOGY 2012; 63:398-404. [PMID: 21881943 DOI: 10.1007/s00248-011-9932-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 08/17/2011] [Indexed: 05/31/2023]
Abstract
Francisella noatunensis subsp. orientalis (syn. Francisella asiatica), the causative agent of franciselliosis in warm-water fish, is a Gram-negative facultative intracellular bacterium. Although it has been characterized as one of the most pathogenic bacteria in fish, the water conditions that allow for its survival and infectious capacities outside the fish host are not known. Data obtained in this project indicate that both temperature and salinity are important factors in the culturability and persistence of F. noatunensis subsp. orientalis in both sea- and freshwater microcosms. These results indicate that culturable F. noatunensis subsp. orientalis persist for longer periods of time and at higher numbers in seawater, and its persistence is inversely related to water temperature. Moreover, the pathogenic properties of the bacteria suspended in water microcosms appear to decrease after only 24 h and become non-infective after 2 days in the absence of the fish host.
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Affiliation(s)
- Esteban Soto
- Department of Pathobiology, School of Veterinary Medicine, Basseterre, Ross University School of Veterinary Medicine, West Farm, Basseterre, St. Kitts, West Indies.
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29
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Soto E, Baumgartner W, Wiles J, Hawke JP. Francisella asiatica as the causative agent of piscine francisellosis in cultured tilapia (Oreochromis sp.) in the United States. J Vet Diagn Invest 2011; 23:821-5. [DOI: 10.1177/1040638711407058] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Francisella asiatica is a Gram-negative, pleomorphic, facultative intracellular, bacterial pathogen that causes acute to chronic disease in a wide variety of warm-water cultured and wild fish species. Outbreaks of francisellosis in warm water fish have been documented in Taiwan, Japan, United Kingdom, Hawaii, and Latin America (including Costa Rica) but the organism has only been reported from the United States on one occasion from hybrid striped bass in California. In 2010, the bacterium was detected from diseased tilapia by culture on cystine heart agar supplemented with hemoglobin and by utilizing an F. asiatica–specific real-time polymerase chain reaction assay. The tilapia ( Oreochromis niloticus) were cultured in an indoor, closed, recirculating aquaculture facility in the Midwest of the United States. The identity of isolates recovered from diseased fish was confirmed as F. asiatica by amplification and sequence comparison of the 16S ribosomal RNA and intracellular growth locus C ( iglC) gene. Gross and microscopic examination of affected tissues revealed the presence of marked anterior renomegaly and splenomegaly with severe granulomatous disease.
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Affiliation(s)
- Esteban Soto
- Louisiana State University, Department of Pathobiological Sciences, School of Veterinary Medicine, Baton Rouge, LA (Soto, Baumgartner, Wiles, Hawke)
- Ross University, Department of Pathobiology, School of Veterinary Medicine, St. Kitts, West Indies (Soto)
| | - Wes Baumgartner
- Louisiana State University, Department of Pathobiological Sciences, School of Veterinary Medicine, Baton Rouge, LA (Soto, Baumgartner, Wiles, Hawke)
- Ross University, Department of Pathobiology, School of Veterinary Medicine, St. Kitts, West Indies (Soto)
| | - Judy Wiles
- Louisiana State University, Department of Pathobiological Sciences, School of Veterinary Medicine, Baton Rouge, LA (Soto, Baumgartner, Wiles, Hawke)
- Ross University, Department of Pathobiology, School of Veterinary Medicine, St. Kitts, West Indies (Soto)
| | - John P. Hawke
- Louisiana State University, Department of Pathobiological Sciences, School of Veterinary Medicine, Baton Rouge, LA (Soto, Baumgartner, Wiles, Hawke)
- Ross University, Department of Pathobiology, School of Veterinary Medicine, St. Kitts, West Indies (Soto)
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Colquhoun DJ, Duodu S. Francisella infections in farmed and wild aquatic organisms. Vet Res 2011; 42:47. [PMID: 21385413 PMCID: PMC3060124 DOI: 10.1186/1297-9716-42-47] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 03/08/2011] [Indexed: 01/08/2023] Open
Abstract
Over the last 10 years or so, infections caused by bacteria belonging to a particular branch of the genus Francisella have become increasingly recognised in farmed fish and molluscs worldwide. While the increasing incidence of diagnoses may in part be due to the development and widespread availability of molecular detection techniques, the domestication of new organisms has undoubtedly instigated emergence of clinical disease in some species. Francisellosis in fish develops in a similar fashion independent of host species and is commonly characterised by the presence of multi-organ granuloma and high morbidity, with varying associated mortality levels. A number of fish species are affected including Atlantic cod, Gadus morhua; tilapia, Oreochromis sp.; Atlantic salmon, Salmo salar; hybrid striped bass, Morone chrysops × M. saxatilis and three-lined grunt, Parapristipoma trilinineatum. The disease is highly infectious and often prevalent in affected stocks. Most, if not all strains isolated from teleost fish belong to either F. noatunensis subsp. orientalis in warm water fish species or Francisella noatunensis subsp. noatunensis in coldwater fish species. The disease is quite readily diagnosed following histological examination and identification of the aetiological bacterium by culture on cysteine rich media or PCR. The available evidence may indicate a degree of host specificity for the various Francisella strains, although this area requires further study. No effective vaccine is currently available. Investigation of the virulence mechanisms and host response shows similarity to those known from Francisella tularensis infection in mammals. However, no evidence exists for zoonotic potential amongst the fish pathogenic Francisella.
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Affiliation(s)
- Duncan J Colquhoun
- Section for Fish health, National Veterinary Institute, Postbox 750 sentrum, 0106 Oslo, Norway.
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Pierson T, Matrakas D, Taylor YU, Manyam G, Morozov VN, Zhou W, van Hoek ML. Proteomic Characterization and Functional Analysis of Outer Membrane Vesicles of Francisella novicida Suggests Possible Role in Virulence and Use as a Vaccine. J Proteome Res 2011; 10:954-67. [DOI: 10.1021/pr1009756] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tony Pierson
- Department of Molecular and Microbiology, George Mason University, Manassas, Virginia 20110, United States
| | - Demetrios Matrakas
- Department of Molecular and Microbiology, George Mason University, Manassas, Virginia 20110, United States
| | - Yuka U. Taylor
- Department of Molecular and Microbiology, George Mason University, Manassas, Virginia 20110, United States
| | - Ganiraju Manyam
- Department of Bioinformatics & Computational Biology, The UT MD Anderson Cancer Center, Houston, Texas, United States
| | - Victor N. Morozov
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110, United States
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia
| | - Weidong Zhou
- Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, Virginia 20110, United States
| | - Monique L. van Hoek
- Department of Molecular and Microbiology, George Mason University, Manassas, Virginia 20110, United States
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110, United States
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Birkbeck TH, Feist SW, Verner-Jeffreys DW. Francisella infections in fish and shellfish. JOURNAL OF FISH DISEASES 2011; 34:173-187. [PMID: 21306585 DOI: 10.1111/j.1365-2761.2010.01226.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A series of recent reports have implicated bacteria from the family Francisellaceae as the cause of disease in farmed and wild fish and shellfish species such as Atlantic cod, Gadus morhua L., tilapia, Oreochromis spp., Atlantic salmon, Salmo salar L., three-line grunt, Parapristipoma trilineatum (Thunberg), ornamental cichlid species, hybrid striped bass Morone chrysops x M. saxatilis and, recently, a shellfish species, the giant abalone, Haliotisgigantea Gmelin. The range of taxa affected will very probably rise as it is likely that there has been considerable under-reporting to date of these disease agents. In common with other Francisella species, their isolation and culture require specialized solid and liquid media containing cysteine and a source of iron. This likely restricted earlier efforts to identify them correctly as the cause of disease in aquatic animals. The most information to date relates to disease in cod, caused by F. noatunensis and tilapia, caused by F. noatunensis subsp. orientalis (also termed F. asiatica), both causing granulomatous inflammatory reactions. Mortalities in both species can be high and, as the disease can likely be transferred via live fish movements, they pose a significant threat to tilapia and cod aquaculture operations. Although the fish-pathogenic Francisella species are classified in the same genus as the human pathogens F. tularensis, causative agent of tularemia, and F. philomiragia, the risk to humans from the fish and shellfish pathogenic Francisella species is considered very low.
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Affiliation(s)
- T H Birkbeck
- University of London Marine Biological Station, Millport, Isle of Cumbrae, Scotland, UK
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In vitro and in vivo efficacy of florfenicol for treatment of Francisella asiatica infection in tilapia. Antimicrob Agents Chemother 2010; 54:4664-70. [PMID: 20713674 DOI: 10.1128/aac.00206-10] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Francisella asiatica is a recently described, Gram-negative, facultative intracellular fish pathogen, known to be the causative agent of francisellosis in warm-water fish. Francisellosis outbreaks have increased in frequency among commercial aquaculture operations and have caused severe economic losses in every case reported. The lack of effective treatments for piscine francisellosis led us to investigate the potential efficacy of florfenicol for inhibition of F. asiatica in vitro and as an oral therapeutic agent in vivo. The MIC of florfenicol for F. asiatica, as determined by the broth dilution method, was 2 μg/ml, which indicates its potential efficacy as a therapeutic agent for treatment of francisellosis. The intracellular susceptibility of the bacterium to florfenicol in tilapia head kidney-derived macrophages (THKDM) was also investigated. Addition of florfenicol to the medium at 10 μg/ml was sufficient to significantly reduce bacterial loads in the THKDM in vitro. Cytotoxicity assays done in infected THKDM also demonstrated drug efficacy in vivo, as determined by lactate dehydrogenase (LDH) release. Levels of LDH released from infected THKDM were significantly lower in macrophages treated with florfenicol (P < 0.001) than in untreated cells. In medicated-feed trials, fish were fed 15 mg of florfenicol/kg of fish body weight for 10 days, and the feeding was initiated at either 1, 3, or 6 days postchallenge. Immersion challenges resulted in 30% mean percent survival in nontreated fish, and fish receiving medicated feed administered at 1 and 3 days postinfection showed higher mean percent survival (100% and 86.7%, respectively). A significant decrease (P < 0.001) in bacterial numbers (number of CFU/g of spleen tissue) was observed in treated groups compared to nontreated infected fish at both 1 and 3 days postchallenge. There were no differences in bacterial burden in the spleens between fish treated 6 days postchallenge and untreated controls. In conclusion, if florfenicol is administered during early stages of infection, it has the potential for effectively treating piscine francisellosis, including the capacity for intracellular penetration and bacterial clearance.
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Soto E, Wiles J, Elzer P, Macaluso K, Hawke JP. Attenuated Francisella asiatica iglC mutant induces protective immunity to francisellosis in tilapia. Vaccine 2010; 29:593-8. [PMID: 20600508 DOI: 10.1016/j.vaccine.2010.06.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 05/15/2010] [Accepted: 06/10/2010] [Indexed: 11/18/2022]
Abstract
Francisella asiatica is a Gram-negative, facultative intracellular bacteria that causes fish francisellosis. Fish francisellosis is a severe sub-acute to chronic granulomatous disease with high mortalities and high infectivity rates in cultured and wild fish. To date, there is no approved vaccine for this widespread emergent disease. The goal of this study was to characterize the efficacy of a defined F. asiatica mutant (ΔiglC) as a live attenuated vaccine against subsequent immersion challenge with the wild-type (WT) organism. In previous work, the ΔiglC was found to be attenuated upon intraperitoneal injection and immersion challenges. In vitro, the ΔiglC exhibited reduced growth in tilapia head-kidney derived macrophages, and was significantly attenuated (p<0.001) as demonstrated by cytopathogenic and apoptosis assays. In this study, the ΔiglC was tested to determine its ability to protect tilapia against challenge with high doses (lethal dose 80) of WT bacteria. Naïve tilapia vaccinated by immersion with a suspension of the ΔiglC and subsequently challenged with WT F. asiatica were protected (90% mean percent survival) from the lethal challenges. F. asiatica-specific antibodies produced in response to immunization with the ΔiglC were subsequently found to protect naïve tilapia against high-dose F. asiatica challenge in passive immunization experiments. Significant protection (p<0.001) was obtained when fish were passively immunized and challenged with 10(4) and 10(5)CFU/fish of WT F. asiatica; but not when challenged with 10(6)CFU/fish. This is the first report of a defined live attenuated strain providing protection against F. asiatica in fish.
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Affiliation(s)
- Esteban Soto
- Department of Pathobiological Sciences, Louisiana State University (LSU)-School of Veterinary Medicine, Skip Bertman Dr., Baton Rouge, LA 70803, USA
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Interaction of Francisella asiatica with tilapia (Oreochromis niloticus) innate immunity. Infect Immun 2010; 78:2070-8. [PMID: 20160018 DOI: 10.1128/iai.01308-09] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Members of the genus Francisella are facultative intracellular bacteria that cause important diseases in a wide variety of animals worldwide, including humans and fish. Several genes that are important for intramacrophage survival have been identified, including the iglC gene, which is found in the iglABCD operon in the Francisella sp. pathogenicity island (FPI). In the present study, we examined the interaction of wild-type Francisella asiatica and a Delta iglC mutant strain with fish serum and head kidney-derived macrophages (HKDM). Both the wild-type and the mutant strains were resistant to killing by normal and heat-inactivated sera. The wild-type F. asiatica is able to invade tilapia head kidney-derived macrophages and replicate vigorously within them, causing apoptosis and cytotoxicity in the macrophages at 24 and 36 h postinfection. The Delta iglC mutant, however, is defective for survival, replication, and the ability to cause cytotoxicity in HKDM, but the ability is restored when the mutant is complemented with the iglC gene. Uptake by the HKDM was mediated partially by complement and partially by macrophage mannose receptors, as demonstrated by in vitro assays. Light and electron microscopy analysis of the infected macrophages revealed intracellular bacteria present in a tight vacuole at 2 h postinoculation and the presence of numerous bacteria in spacious vacuoles at 12 h postinfection, with some bacteria free in the cytoplasm.
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