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1.
It has been demonstrated that heat-stable (presumably antibody) and heat-labile (presumably complement) components are necessary to prevent the growth of Vibrio anguillarum in in vitro experiments with trout immune serum and mucus. Anti-V. anguillarum agglutinins were found in the body mucus of intraperitoneally immunized rainbow trout (Salmo gairdneri) 3–6 weeks after serum agglutination titers of 131072 or greater were attained. A component of rainbow trout body mucus was found to be indistinguishable from serum immunoglobulin by immunodiffusion and immunoelectrophoresis.  相似文献   

2.
Nineteen strains of Vibrio anguillarum were examined by means of several immunological methods. Nine other strains belonging to the genera Vibrio, Aeromonas and Pseudomonas were also examined for comparison.Lipopolysaccharides were prepared from seven of the V. anguillarum strains. The lipopolysaccharides seem to be species-specific for V. anguillarum, not being detected in any of the other strains examined. Common antigens are also found in V. anguillarum and other species of marine bacteria.The strains of V. anguillarum fall into three different serological groups according to the type of lipopolysaccharide in the cell wall. One of the groups comprises only one strain, this strain being the only one not isolated from diseased fish.The lipopolysaccharides were used in an indirect haemagglutination test. Inhibition of this haemagglutination with tissue extracts from diseased fish can be used for practical purposes in the diagnosis of vibriosis.  相似文献   

3.
Abstract. Chinook salmon, Oncorhynchus tshawytscha (Walbaum), and rainbow trout, Salmo gairdneri Richardson, were used to determine if sublethal copper exposure would increase their susceptibility to Vibrio anguillarum infection. Fish were pretreated with copper at fractional levels of the 96 h copper LC50 before exposure to the pathogen. Mortality by vibriosis was greater among fish exposed to 9% of the copper LC50 for 96 h than unexposed fish. Peak susceptibility to vibriosis depended in part on the interaction of exposure time and copper concentration. The higher copper concentrations produced peak susceptibility to infection in shorter time periods. After the peak of susceptibility, sensitivity to infection declined to near control levels in those fish where exposure was continued. Rainbow trout stressed by copper required about 50% fewer pathogens to induce a fatal infection than non-copper exposed fish.  相似文献   

4.
《水生生物资源》1999,12(5):343-350
Haemocytes of Mytilus edulis, allowed to attach to the plastic surface of a tissue culture plate in the presence of haemolymph, were observed by time-lapse video recording. When bacteria were added at concentrations of 10 or 50 bacteria per haemocyte, certain bacterial strains caused rounding of the cells within 2–3 h. Haemolymph was necessary for the rounding to occur; if bacteria were added in sterile seawater there was no significant difference in the number of rounded cells between control and bacteria-treated cultures for up to 4 h. The haemolymph factor required for this activity was active at 1/64 dilution in seawater, was sensitive to trypsin treatment, and activity was halved on heating at 56 or 100 °C for 30 min. For the most toxic bacteria tested, Vibrio alginolyticus NCMB 1339 and Vibrio anguillarum A7, haemocyte cell rounding appeared to be induced by a very small number of bacterial cells. Bacteria-free culture supernatant of V. anguillarum 2981 induced rounding of haemocytes in a dose-dependent manner, with 50 % of cells being rounded at a dilution of approximately 1/500 of the culture supernatant. In a survey of 226 bacterial isolates, those isolated from incidents of disease in a bivalve hatchery were significantly more toxic towards haemocytes than bacteria isolated from hatcheries without disease or from turbot hatcheries.  相似文献   

5.
The antibacterial effect of Lactococcus lactis subsp. lactis against the fish pathogen Vibrio anguillarum was determined in Artemia franciscana nauplii and in European sea bass (Dicentrarchus labrax) larvae fed with ten pulses of nauplii enriched with L. lactis. The evaluation of the bactericidal activity of the extracellular products of L. lactis in vitro showed inhibition of growth of Vibrio (Listonella) anguillarum and Photobacterium damselae subsp. piscicida. The incorporation of L. lactis in Artemia nauplii did not affect their survival and offered protection in a challenge with V. anguillarum, significantly increasing LD50. The administration of Artemia nauplii enriched with L. lactis for 48 h to sea bass larvae for five consecutive days had no adverse effect on survival of fish. In an in vivo challenge test with V. anguillarum using sea bass larvae, fish treated with nauplii enriched with the probiotic L. lactis showed significantly (P < 0.001) increased survival rates of 81 % compared with the untreated group of challenged fish (24 %). Our results indicate that L. lactis is a probiotic suitable to be used for the prevention of vibriosis in fish larvae and can be safely administered through their live feed Artemia nauplii.  相似文献   

6.
Vibrio anguillarum is a major pathogenic bacterium that causes vibriosis and septicemia in fish and shellfish. In this study, we identified the groESL genes, which encode bacterial chaperonins, from V. anguillarum. The groE gene cluster consisted of a 291-bp groES gene, a 69-bp intergenic spacer region, and a 1,635-bp groEL gene order. Sequence analysis with the groESL gene of Vibrio species exhibited that the groEL gene was more species-specific and suitable than the groES gene for V. anguillarum detection. Owing to the difficulty in distinguishing V. anguillarum from the closely related V. ordalii, we compared the sequences of groEL from V. anguillarum and the groEL homolog hsp60 from V. ordalii, in order to design a primer set based on a region dissimilar between the two. PCR with the groEL primer set produced a clear 195-bp amplicon in six serotypes of V. anguillarum, whereas 23 Vibrio species of 39 samples, including V. ordalii, and 10 species of enteric bacteria gave no bands. PCR using the groEL primers also amplified a unique product from V. anguillarum-infected flounder and oyster tissues. These results demonstrate that the groEL-target PCR assay is a sensitive and species-specific tool for the detection of V. anguillarum infection.  相似文献   

7.
Rainbow trout, Oncorhynchus mykiss (Walbaum), are able to raise a protective immune response against Aeromonas salmonicida subsp. salmonicida (AS) following injection vaccination with commercial vaccines containing formalin‐killed bacteria, but the protection is often suboptimal under Danish mariculture conditions. We elucidated whether protection can be improved by increasing the concentration of antigen (formalin‐killed bacteria) in the vaccine. Rainbow trout juveniles were vaccinated by intraperitoneal (i.p.) injection with a bacterin of Aeromonas salmonicida subsp. salmonicida strain 090710‐1/23 in combination with Vibrio anguillarum serotypes O1 and O2a supplemented with an oil adjuvant. Three concentrations of AS antigens were applied. Fish were subsequently challenged with the homologous bacterial strain administered by perforation of the tail fin epidermis and 60‐s contact with live A. salmonicida bacteria. The infection method proved to be efficient and could differentiate efficacies of different vaccines. It was shown that protection and antibody production in exposed fish were positively correlated to the AS antigen concentration in the vaccine.  相似文献   

8.
Strains of Vibrio anguillarum isolated from rainbow trout (Salmo gairdneri) and saithe (Gadus virens) have been studied and compared, and strains to be used for further investigations are described.  相似文献   

9.
Vibrio anguillarum is an aggressive and halophilic bacterial pathogen most commonly originating from seawater. Vibrio anguillarum presence in fisheries and aquaculture facilities causes significant morbidity and mortality among aquaculture species primarily from haemorrhaging of the body and skin of the infected fish that eventually leads to death, collectively recognized as the disease vibriosis. This study served to develop a non‐probe, multiplex real‐time PCR assay to rapidly detect V. anguillarum presence in seawater. Specific primers targeting genes vah1, empA and rpoN of V. anguillarum were selected for multiplex reaction among 11 different primer sets and the extension step was eliminated. Primer concentration, denaturation time as well as annealing time and temperature of DNA amplification were optimized, thus reducing reaction duration. The two‐step, non‐probed multiplex real‐time PCR set forth by this study detects as little as 3 CFU mL?1 of V. anguillarum presence in sea water, without enrichment cultivation, in 70 min with molecular precision and includes melting curve confirmation.  相似文献   

10.
Lumpfish (Cyclopterus lumpus), a native fish of the North Atlantic Ocean, is utilized as cleaner fish to biocontrol sea lice infestations in Atlantic salmon aquaculture. However, bacterial infections are affecting cleaner fish performance. Vibrio anguillarum, the aetiological agent of vibriosis, is one of the most frequent bacterial infections in lumpfish, and effective vaccine programmes against this pathogen have been identified as a high priority for lumpfish. Vibrogen‐2 is a commercial polyvalent bath vaccine that contains formalin‐inactivated cultures of V. anguillarum serotypes O1 and O2, and Vibrio ordalii. In this study, we evaluated Vibrogen‐2 efficacy in lumpfish against a local isolated V. anguillarum strain. Two groups of 125 lumpfish were bath‐immunized, bath‐boost‐immunized at four weeks post‐primary immunization, and intraperitoneally (i.p.) boost‐immunized at eight weeks post‐primary immunization. The control groups were i.p. mock‐immunized with PBS. Twenty‐seven weeks post‐primary immunization, the fish were i.p. challenged with 10 or 100 times the V. anguillarum J360 LD50 dose. After the challenge, survival was monitored daily, and samples of tissues were collected at ten days post‐challenge. Commercial vaccine Vibrogen‐2 reduced V. anguillarum tissue colonization and delayed mortality but did not confer immune protection to C. lumpus against the V. anguillarum i.p. challenge.  相似文献   

11.
The aro genes in bacteria encode enzymes needed for the biosynthesis of aromatic amino acids, and mutant bacteria that are defective in the enzymes can replicate only a limited number in vertebrates owing to the lack or scarceness of chorismate, through which the mutant bacteria of the aro genes become attenuated. In the present study, the 5‐enolpyruvylshikimate‐3‐phosphate synthase (aroA) gene‐knockout Vibrio anguillarum (ΔaroA V. anguillarum) were generated by the allelic exchange method, and its vaccine potential was evaluated in the olive flounder, Paralichthys olivaceus, by comparing the protective efficacy of a formalin‐inactivated V. anguillarum. The LD50 (50% lethal dose) value of ΔaroA V. anguillarum was 1000 times higher than that of wild‐type V. anguillarum in olive flounder fingerlings, and the growth of ΔaroA V. anguillarum was significantly suppressed by coincubation with nonimmune olive flounder serum compared with that of wild‐type V. anguillarum. The survival rates and serum agglutination titers of fish immunized with ΔaroA V. anguillarum were significantly higher than those of fish immunized with the same amount of formalin‐inactivated V. anguillarum, suggesting that although the inactivated V. anguillarum vaccine can provide a high protection in olive flounder, the protective efficacy can be enhanced by immunization with an auxotrophic mutant ΔaroA V. anguillarum.  相似文献   

12.
本研究分析了鳗弧菌(Vibrio anguillarum)O1/O2血清型二价灭活疫苗免疫大菱鲆后的抗体持续期和免疫保护期。以鳗弧菌O1血清型VAM003株和O2血清型VAM007株为抗原制备了福尔马林灭活二价疫苗,将疫苗按照三种剂量(10~7 cells/尾、10~8 cells/尾、10~9 cells/尾)以腹腔注射途径免疫大菱鲆,在免疫后3 d、7 d、14 d、30 d、60 d、90 d、120 d、150 d,用血清凝集实验检测了免疫鱼血清的VAM003和VAM007抗体效价,用攻毒实验检测了疫苗的免疫保护率(RPS)。结果显示,在免疫后7 d三个剂量组的大菱鲆均产生了特异抗体,并获得27%～60%的RPS。三个剂量组大菱鲆的O1血清型抗体持续期分别90 d (10~7 cells/尾组)、150 d (10~8 cells/尾组)、150 d (10~9cells/尾组),而三个剂量组大菱鲆的O2血清型抗体持续期均150 d。三个剂量组的大菱鲆获得的免疫保护持续期均150 d;以RPS75%为有效免疫保护,各剂量组大菱鲆抵抗O1血清型病原感染的有效免疫保护期为:14～120d(10~7 cells组)、14～120 d (10~8 cells/尾)、14～150 d (10~9 cells/尾),抵抗O2血清型病原感染的有效免疫保护期为:14～60 d (10~7 cells组)、14～120 d (10~8 cells/尾)、14～120 d (10~9 cells/尾)。研究结果表明鳗弧菌二价灭活疫苗可为大菱鲆提供有效而稳定的免疫保护,获得的抗体持续期和免疫保护期为该疫苗的临床中试研究提供了基础。  相似文献   

13.
Vibrio anguillarum, which is part of normal microflora on fish, is the causative agent of vibriosis in aquaculture. It is speculated that V. anguillarum does not affect the host in most situations, but can cause a severe disease once the host is compromised. In the study reported herein, skin‐injured and intestine‐injured zebrafish, Danio rerio, were established as a model to mimic the natural infection caused by V. anguillarum when fish suffered an injury to a mucosal surface. Our results showed the lethal dose to 50% of the population (LD50) of skin‐injured zebrafish was 6.8 × 103 colony‐forming unit (CFU)/mL, which was much lower than intestine‐injured zebrafish (1.9 × 106 CFU/mL) or non‐injured zebrafish (5.5 × 106 CFU/mL). With the quantitative polymerase chain reaction and immunohistochemical analysis, we found that V. anguillarum proliferated rapidly in the skin and muscle after the bacteria entered into the host via the skin injury. The bacteria were subsequently transported to the immune organs and then caused a systemic infection in the fish. However, mortality of skin‐injured zebrafish significantly decreased if the fish were allowed to heal. These results indicate that minimizing injury to the mucosal surfaces of fish, especially the skin, will reduce infections caused by V. anguillarum.  相似文献   

14.
Abstract. The histopathology associated with naturally acquired vibriosis in chum salmon, Oncorhynchus keta (Walbaum), fingerlings caused by Vibrio anguillarum was compared with that caused by infection with Vibrio ordalii. Pathogenesis of the two forms was found to be different. Bacteraemia caused by V. anguillarum occurred in the early stages with pronounced histopathological changes in blood, loose connective tissue, kidney, spleen, gills and posterior gastrointestinal tract. Bacterial cells appeared uniformly dispersed throughout the affected tissues but were most abundant in the blood. With V. ordalii, bacteraemia developed only in late stages of the disease and the concentration of bacterial cells per ml of blood was less than in the V. anguillarum infection by a factor of 102–103. Tissues with most pronounced changes were skeletal and cardiac muscle, anterior and posterior gastrointestinal tract and the gills. Vibrio ordalii observed in the tissues was not evenly dispersed but was present within tissue as colonies or aggregates of cells. The differences in pathology observed in naturally infected chum salmon were produced experimentally with each pathogen by waterborne exposure of chum; coho, Oncorhynchus kisutch (Walbaum); and chinook salmon, Oncorhynchus tshawytscha (Walbaum). Severe decreases in circulating leucocytes accompanied bacteraemia caused by either bacterial species.  相似文献   

15.
The location and cell damage caused by Vibrio anguillarum, the causative agent of classical vibriosis, within the developing gut of the newly hatched sea bass, Dicentrarchus labrax (L.), is unknown. A gnotobiotic sea bass model was used to investigate the early interactions of V. anguillarum with sea bass larvae. In the present study, germ‐free sea bass larvae were orally exposed to a V. anguillarum HI‐610 pathogen labelled with the green fluorescent protein (GFP‐HI‐610) and sampled at regular intervals. Pathogenic colonization of gut enterocytes was observed 2 h post‐exposure (p.e.) and onwards, whereas bacteria within the swim bladder were visualized 48 h p.e and onwards. Ultrastructural findings demonstrated direct bacterial contact with the host cell in the oesophageal mucosa and putative attachment to microvilli of mid‐ and hindgut enterocytes. The present findings form a starting point for studies assessing the impact of potential candidates (probiotics, prebiotics, antimicrobial peptides) to mitigate bacterial virulence.  相似文献   

16.
Because of the evolving resistance of microorganisms to existing antibiotics, there is an increasing need for new antibiotics not only in human but also in veterinary medicine. Competition for space and nutrients led to the evolution of antimicrobial defence strategies in the aquatic environment. Therefore, aquatic organisms, e.g., seaweeds, offer a particularly rich source of potential new drugs. The aim of our studies was to identify seaweeds, which possess activities against fish pathogenic bacteria and could be an alternative to the commonly used antibiotics in aquaculture.Dichloromethane, methanole and water extracts of 26 species of cultivated seaweeds were screened for their antibacterial activities against five fish pathogenic bacteria strains (Aeromonas salmonicida ssp. salmonicida, Aeromonas hydrophila ssp. hydrophila, Pseudomonas anguilliseptica, Vibrio anguillarum, Yersinia ruckeri). The dichloromethane extracts of Asparagopsis armata, Ceramium rubrum, Drachiella minuta, Falkenbergia rufolanosa, Gracilaria cornea and Halopitys incurvus showed strong antibacterial activities. V. anguillarum and P. anguilliseptica were the two most susceptible bacteria strains. The screening results confirm the possible use of seaweeds as a source of antimicrobial compounds or as a health-promoting food for aquaculture.  相似文献   

17.
The research facilities at the fish experimental station at Sunndalsöra are described. The design of a selection experiment with salmon and sea trout is presented. The station is also used for other purposes, such as investigations into nutrition, pathology and environmental factors.In this paper analyses of observed differences to vibrio disease (Vibrio anguillarum) are reported. Significant differences in resistance between river strains of salmon parr were found. The difference between localities are supposed to be partly heritable.The data were also used to estimate the heritability on an intra-river basis. The estimates were 0.12 and 0.07 based on the sire and dam component, respectively. It is concluded that selection against vibrio disease will result in genetic change.  相似文献   

18.
Vibrio anguillarum, also known as Listonella anguillarum, is the causative agent of vibriosis, a deadly haemorrhagic septicaemic disease affecting various marine and fresh/brackish water fish, bivalves and crustaceans. In both aquaculture and larviculture, this disease is responsible for severe economic losses worldwide. Because of its high morbidity and mortality rates, substantial research has been carried out to elucidate the virulence mechanisms of this pathogen and to develop rapid detection techniques and effective disease‐prevention strategies. This review summarizes the current state of knowledge pertaining to V. anguillarum, focusing on pathogenesis, known virulence factors, diagnosis, prevention and treatment.  相似文献   

19.
Since 2011, high mortality rates and symptoms consistent with vibriosis have been observed in farmed amberjack (Seriola dumerili) in Japan. To identify 41 strains isolated from diseased amberjack, a multilocus sequence analysis using nine concatenated genes (ftsZ, gapA, gyrB, mreB, pyrH, recA, rpoA, topA and 16S rRNA) was conducted. Twenty‐seven strains were identified as Vibrio harveyi, suggesting an epidemic of V. harveyi infection in amberjack farms. Other strains were identified as Vibrio anguillarum, Vibrio owensii and Photobacterium damselae subsp. damselae. To develop an efficient diagnostic method for vibriosis in amberjack, a multiplex PCR system was developed to identify V. anguillarum, V. harveyi and P. damselae subsp. damselae. The method successfully discriminated between these three bacterial species, with amplification products of 350 bp for V. anguillarum, 545 bp for V. harveyi and 887 bp for P. damselae subsp. damselae and can be used for diagnosis in aquaculture farms.  相似文献   

20.
Vibrio anguillarum is the causative agent of vibriosis, a deadly haemorrhagic septicaemic disease affecting various marine and fresh/brackish water fish, bivalves and crustaceans. However, the diversity and virulence mechanisms of this pathogen are still insufficiently known. In this study, we aimed to increase our understanding of V. anguillarum diversity and virulence through comparative genome analysis of 15 V. anguillarum strains, obtained from different hosts or non‐host niches and geographical regions, among which 10 and 5 strains were found to be virulent and avirulent, respectively, against sea bass larvae. First, the 15 draft genomes were annotated and screened for putative virulence factors, including genes encoding iron uptake systems, transport systems and non‐ribosomal peptide synthetases. Second, comparative genome analysis was performed, focusing on single nucleotide polymorphisms (SNPs) and small insertions and deletions (InDels). Five V. anguillarum strains showed a remarkably high nucleotide identity. However, these strains comprise both virulent and avirulent strains towards sea bass larvae, suggesting that differences in virulence may be caused by subtle nucleotide variations. Clearly, the draft genome sequence of these 15 strains represents a starting point for further genetic research of this economically important fish pathogen.  相似文献   

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