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Kurt Buchmann - One of the best experts on this subject based on the ideXlab platform.

  • protective effect of in feed specific igm towards Yersinia ruckeri in rainbow trout
    Fish & Shellfish Immunology, 2019
    Co-Authors: Inger Dalsgaard, Jiwan Kumar Chettri, Kurt Buchmann, Azmi Aljubury, Marie Bendix Hansen, Allan Otto Fog Lihme, Peter M H Heegaard
    Abstract:

    Abstract Tightened regulations and an environmentally friendly approaches in fish production have greatly reduced the use of antibiotics but green solutions are continuously being explored. The use of functional feed may have a potential in the aquaculture sector in securing biomass and minimizing the loss from disease. In the present study, we tested the concept that blood from the fish slaughterhouse can be used for mass purification of specific antibodies which subsequently can be used for feeding fish and thereby confer protection against diseases. IgM was purified from serum from Yersinia ruckeri vaccinated rainbow trout and an IgM sandwich ELISA was developed for quantification of rainbow trout IgM. The purified IgM was encapsulated in alginate microparticles and top-coated in fish feed. IgM re-extracted from the alginate microparticles was shown to retain high reactivity towards Y. ruckeri antigens indicating that its bioactivity remained intact after encapsulation. IgM release from the alginate microparticles was only observed at high pH (pH 8.2) and minimal at low pH, indicating protection of IgM at low pH in the fish stomach during passage. In a feeding – challenge experiment (feeding 1 week before Y. ruckeri challenge and for two weeks following challenge), a statistically non-significant 10% lower mortality was observed in the high dose (400 μg IgM/fish/day fed over 3 weeks) group.

  • effects of soluble immunostimulants on mucosal immune responses in rainbow trout immersion vaccinated against Yersinia ruckeri
    Aquaculture, 2018
    Co-Authors: Jakob Skov, Inger Dalsgaard, Jiwan Kumar Chettri, Rzgar M Jaafar, Per W Kania, Kurt Buchmann
    Abstract:

    Abstract Immersion vaccination of rainbow trout against Yersinia ruckeri infection is an established method to prevent enteric red mouth disease (ERM) but the effect is inferior to injection vaccination and the duration of protection is limited to less than six months. Adjuvants in vaccines may in general elevate the immune response and the present work elucidates how ERM immersion vaccination of trout in combination with exposure to soluble adjuvants, Montanide™ IMS 1312 VG PR and β-glucan, affects immune reactions. The former adjuvant, when used alone, induced a slightly increased protection (not statistically significant) whereas β-glucan did not increase protection. Adjuvant-treated and non-exposed groups showed elevated plasma lysozyme activity after challenge with Y. ruckeri. Specific antibody production was not positively affected by combining adjuvant and vaccine. Overall expression of immune genes tested was generally manifold higher in gills compared to skin. Only genes encoding SAA and IL-17C1 were expressed at a higher level in skin. Dynamic differences between the gill and skin compartments were also recorded for genes encoding cytokines (TNF-α, IL-1β, IL-6, IL-10, IL-12, IL-17A/F2, IL-17C1, IL-17C2, IL-22), immunoglobulins (IgM, IgD, IgT), cell markers (CD8α, TCR-β) and acute phase reactants (SAA, lysozyme). These genes were upregulated 24 h post-vaccination in fish gills exposed to both vaccine-adjuvant combinations when compared to fish exposed to vaccine alone. After a few weeks no vaccine induced reaction was seen and after challenge with bacteria mainly unvaccinated fish responded. Adjuvants used in combination with immersion vaccine clearly influences immune reactions and may improve duration and protection but further potency tests should be performed.

  • effect of oral booster vaccination of rainbow trout against Yersinia ruckeri depends on type of primary immunization
    Fish & Shellfish Immunology, 2017
    Co-Authors: Rzgar M Jaafar, Inger Dalsgaard, Per W Kania, Azmi Aljubury, Asma Mohammadkarami, Kurt Buchmann
    Abstract:

    Abstract Vaccination of rainbow trout against Enteric Redmouth Disease (ERM) caused by Yersinia ruckeri can be successfully performed by administering vaccine (a bacterin consisting of formalin killed bacteria) by immersion, bath or injection. Booster immunization is known to increase the protection of fish already primed by one of these vaccination methods. Oral vaccination of trout (administering vaccine in feed) is an even more convenient way of presenting antigen to the fish but the effect of an oral booster has not previously been described in detail. The present work describes to what extent protection may be enhanced by oral boostering following priming with different administration methods. The study confirms that vaccination by 30 s dip into a bacterin (diluted 1:10) may confer a significant protection compared to non-vaccinated fish. The immunity may be optimized by booster immunization either provided as dip (most effective), bath (less effective) or orally (least effective). Oral immunization may be used as booster after dip but applied as a single oral application it induced merely a slight and statistically non-significant response. It is noteworthy that primary oral immunization followed by an oral booster vaccination showed a trend for an even weaker response. It should be investigated if continued exposure to a low antigen concentration – as performed by two oral immunizations - may induce tolerance to the pathogen and thereby leave the fish more vulnerable.

  • antimicrobial peptide cap18 and its effect on Yersinia ruckeri infections in rainbow trout oncorhynchus mykiss walbaum comparing administration by injection and oral routes
    Journal of Fish Diseases, 2017
    Co-Authors: Jiwan Kumar Chettri, Inger Dalsgaard, Foojan Mehrdana, Egon Bech Hansen, Anna Elisabeth Ebbensgaard, Michael Toft Overgaard, Anne Hjorngaard Lauritsen, Kurt Buchmann
    Abstract:

    The antimicrobial peptide CAP18 has been demonstrated to have a strong in vitro bactericidal effect on Yersinia ruckeri, but its activity in vivo has not been described. In this work, we investigated whether CAP18 protects rainbow trout Oncorhynchus mykiss (Walbaum) against enteric red mouth disease caused by this pathogen either following i.p. injection or by oral administration (in feed). It was found that injection of CAP18 into juvenile rainbow trout before exposure to Y. ruckeri was associated with lowered mortality compared to non-medicated fish although it was less effective than the conventional antibiotic oxolinic acid. Oral administration of CAP18 to trout did not prevent infection. The proteolytic effect of secretions on the peptide CAP18 in the fish gastrointestinal tract is suggested to account for the inferior effect of oral administration.

  • oil adjuvant elevates protection of rainbow trout oncorhynchus mykiss following injection vaccination against Yersinia ruckeri
    Fish & Shellfish Immunology, 2016
    Co-Authors: Rzgar M Jaafar, Inger Dalsgaard, Jiwan Kumar Chettri, Jakob Skov, Per W Kania, Azmi Aljubury, Kurt Buchmann
    Abstract:

    Enteric redmouth disease (ERM) caused by the fish pathogen Yersinia ruckeri is a major threat to freshwater production of rainbow trout throughout all life stages. Injection vaccination of rainbow trout against Y. ruckeri infection has been shown to confer better protection compared to the traditionally applied immersion vaccination. It may be hypothesized, based on experience from other vaccines, that adjuvants may increase the protective level of ERM injection vaccines even more. Controlled comparative vaccination studies conducted to investigate effects of the oil adjuvant MontanideTM ISA 763 A VG when added to an experimental Y. ruckeri bacterin (containing both biotype 1 and 2 of serotype O1). A total of 1000 fish with mean weight 19 g was divided into five different groups (in duplicated tanks 2 × 100 fish per group) 1) nonvaccinated control fish (NonVac), 2) fish injected with a commercial vaccine (AquaVac ReleraTM) (ComVac), 3) fish injected with an experimental vaccine (ExpVac), 4) fish injected with an experimental vaccine + adjuvant (ExpVacAdj) and 5) fish injected with adjuvant alone (Adj). Injection of the experimental vaccine (both adjuvanted and non-adjuvanted) induced a significantly higher antibody (IgM) level, increased occurrence of IgM cells in spleen tissue and significant up-regulation of several immune genes. Additional experiments using a higher challenge dosage suggested an immune enhancing effect of the adjuvant as the challenge produced 100% mortality in the NonVac group, 60% mortality in both of ComVac and Adj groups and only 13 and 2.5% mortalities in the ExpVac and the ExpVacAdj groups, respectively.

Jesus L Romalde - One of the best experts on this subject based on the ideXlab platform.

  • multilocus variable number tandem repeat analysis of Yersinia ruckeri confirms the existence of host specificity geographic endemism and anthropogenic dissemination of virulent clones
    Applied and Environmental Microbiology, 2018
    Co-Authors: Snorre Gulla, Timothy J. Welch, David W Vernerjeffreys, Jesus L Romalde, Michael J Ormsby, Andrew J Barnes, David Ryder, Jeremy Carson, Karin Lagesen, Robert L Davies
    Abstract:

    A Multi-Locus Variable number of tandem repeat Analysis (MLVA) assay was developed for epizootiological study of the internationally significant fish pathogen Yersinia ruckeri , which causes yersiniosis in salmonids. The assay involves amplification of ten Variable Number of Tandem Repeat (VNTR) loci in two five-plex PCR reactions, followed by capillary electrophoresis. A collection of 484 Y. ruckeri isolates, originating from various biological sources and collected from four continents over seven decades, was analysed. Minimum spanning tree cluster analysis of MLVA profiles separated the studied population into nine major clonal complexes, and a number of minor clusters and singletons. The major clonal complexes could be associated with host species, geographic origin and serotype. A single large clonal complex of serotype O1 isolates dominating the yersiniosis situation in international rainbow trout farming suggests anthropogenic spread of this clone, possibly related to transport of fish. Moreover, sub-clustering within this clonal complex indicates putative transmission routes and multiple biotype shift events. In contrast to the situation in rainbow trout, Y. ruckeri strains associated with disease in Atlantic salmon appear as more or less geographically isolated clonal complexes. A single complex of serotype O1 exclusive to Norway was found to be responsible for almost all major yersiniosis outbreaks in modern Norwegian salmon farming, and site-specific sub-clustering further indicates persistent colonisation of freshwater farms in Norway. Identification of genetically diverse Y. ruckeri isolates from clinically healthy fish and environmental sources also suggests the widespread existence of less virulent or avirulent strains. Importance This comprehensive population study substantially improves our understanding of the epizootiological history and nature of an internationally important fish pathogenic bacterium. The MLVA assay developed and presented represents a high-resolution typing tool particularly well suited for Yersinia ruckeri infection tracing, selection of strains for vaccine inclusion, and risk assessment. The ability of the assay to separate isolates into geographically linked and/or possibly host-specific clusters reflects its potential utility for maintenance of national biosecurity. The MLVA is internationally applicable, robust, and provides clear, unambiguous and easily interpreted results. Typing is reasonably inexpensive, with a moderate technological requirement, and may be completed from a harvested colony within a single working day. As the resulting MLVA profiles are readily portable, any Y. ruckeri strain may rapidly be placed in a global epizootiological context.

  • a polyphasic approach to study the intraspecific diversity of Yersinia ruckeri strains isolated from recent outbreaks in salmonid culture
    Veterinary Microbiology, 2012
    Co-Authors: Asmine Bastardo, Jesus L Romalde, Carmen Ravelo
    Abstract:

    A polyphasic analysis was carried out on Yersinia ruckeri strains isolated from recently outbreaks in vaccinated fish using a combination of different phenotypic and molecular typing methods in order to study their variability and epidemiological relationships. Eighty strains were subjected to biotyping with conventional tests and API 20E system, serotyping, outer membrane protein (OMP) and lipopolysaccharide (LPS) profiling, and genetic fingerprinting by ERIC-PCR and REP-PCR techniques. The strains showed a high diversity, as evidenced by the formation of different phenotypic groups mainly related to the serotypes, LPS and OMP profiles. The diversity among all isolates, calculated as Simpson's diversity index (Di), varied between 0.35 (REP-PCR) and 0.70 (OMP). The most discriminative values (Di value ≥0.86) were obtained from any combination of three methods including biotype, serotype, API 20E profile, LPS or OMP. With the combination of all typing methods used a Di value of 0.90 was obtained. Association between different groups to the host species was evidenced. Furthermore, it seems that strains with similar characteristics are associated with recent outbreaks occurred in vaccinated fish in certain geographical areas. Our results emphasize the usefulness of using a combination of several different typing methods for epidemiological and bacterial diversity studies.

  • multilocus sequence typing reveals high genetic diversity and epidemic population structure for the fish pathogen Yersinia ruckeri
    Environmental Microbiology, 2012
    Co-Authors: Carmen Ravelo, Asmine Bastardo, Jesus L Romalde
    Abstract:

    Yersinia ruckeri is the causative agent of enteric redmouth in fish and one of the major bacterial pathogens causing losses in salmonid aquaculture. Previously typing methods, including restriction enzyme analysis, pulsed-field gel electrophoresis and multilocus enzyme electrophoresis (MLEE) have indicated a clonal population structure. In this work, we describe a multilocus sequence typing (MLST) scheme for Y.ruckeri based on the internal fragment sequence of six housekeeping genes. This MLST scheme was applied to 103 Y.ruckeri strains from diverse geographic areas and hosts as well as environmental sources. Sequences obtained from this work were deposited and are available in a public database (http://publmst.org/yruckeri/). Thirty different sequence types (ST) were identified, 21 of which were represented by a single isolate, evidencing high genetic diversity. ST2 comprised more than one-third of the isolates and was most frequently observed among isolates from trout. Two major clonal complexes (CC) were identified by eBURST analysis showing a common evolutionary origin for 94 isolates forming 21 STs into CC1 and for 6 isolates of 6 STs in the CC2. It was also possible to associate some unique ST with isolates from recent outbreaks in vaccinated salmonid fish.

  • phenotypical and genetic characterization of Yersinia ruckeri strains isolated from recent outbreaks in farmed rainbow trout oncorhynchus mykiss walbaum in peru
    Aquaculture, 2011
    Co-Authors: Carmen Ravelo, Asmine Bastardo, Veronica Sierralta, Jorge Leon, Jesus L Romalde
    Abstract:

    Abstract A total of 30 strains of Yersinia ruckeri causing recent outbreaks in Peruvian trout culture systems, were studied by means of biochemical characteristics, serology, lipopolysaccharide (LPS) and outer membrane protein (OMP) analysis, and ERIC and REP PCR fingerprinting. All the Peruvian isolates were found to be fermentative, oxidase negative and positive for decarboxylation of lysine and ornithine and utilization of glucose and mannitol, allowing their presumptive identification as Y. ruckeri . Sequencing of the 16S rRNA gene confirmed that isolates were indeed Y. ruckeri (> 99.98% identity). Although most of the strains studied were motile and lipase positive corresponding to the biotype 1 of Y. ruckeri , 5 of these strains were negative from both tests, being identified as biotype 2. In addition, drug susceptibility tests determined high sensitivity to sulfamethoxazole/trimethoprim, oxytetracycline, ampicillin and enrofloxacin in all the isolates. Serologically, all the Peruvian strains studied were identified as belonging to the serotype O1 subgroup a. Analysis of the lipopolysaccharide (LPS) as well as total and outer membrane proteins (OMPs) profiles and the correspondent inmunoblotting, supported these results. Genotyping performed by means of ERIC- and REP-PCR determined major correlation of the Peruvian isolates with the type strain NCIMB 2194 T regardless of the biotype.

  • serological and molecular heterogeneity among Yersinia ruckeri strains isolated from farmed atlantic salmon salmo salar in chile
    Diseases of Aquatic Organisms, 2011
    Co-Authors: Asmine Bastardo, Harry Bohle, A E Toranzo, Carmen Ravelo, Jesus L Romalde
    Abstract:

    We investigated 11 strains of Yersinia ruckeri, the causative agent of enteric redmouth disease (ERM), that had been isolated from Atlantic salmon Salmo salar L. farmed in Chile and previously vaccinated against ERM. Phylogenetic analysis of the 16S rRNA gene sequences confirmed the identification of the salmon isolates as Y. ruckeri. A comparative analysis of the biochemical characteristics was made by means of traditional and commercial miniaturised methods. All studied isolates were motile and Tween 80 positive, and were identified as biotype 1. In addition, drug susceptibility tests determined high sensitivity to sulphamethoxazole/trimethroprim, oxytetracycline, ampicillin and enrofloxacin in all isolates. Serological assays showed the presence of O1a, O1b and O2b serotypes, with a predominance of the O1b serotype in 9 strains. Analysis of the lipopolysaccharide profiles and the correspondent immunoblot confirmed these results. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of the outer membrane proteins revealed that all Chilean strains had profiles with a molecular weight range between 34 and 55 kDa, with 3 distinct groups based on differences in the major bands. Genotyping analyses by enterobacterial repetitive intergenic consensus (ERIC-) and repetitive extragenic palindromic (REP-)PCR techniques clearly indicated intraspecific genetic diversity among Chilean Y. ruckeri strains.

Inger Dalsgaard - One of the best experts on this subject based on the ideXlab platform.

  • immersion vaccines against Yersinia ruckeri infection in rainbow trout comparative effects of strain differences
    Journal of Fish Diseases, 2021
    Co-Authors: He Yang, Inger Dalsgaard, Ding Zhujin, Moonika Haahr Marana, Jaafar Rzgar, Mathiessen Heidi, Karami M Asma, Kania W Per, Buchmann Kurt
    Abstract:

    The protective effects of autogenous and commercial ERM immersion vaccines (bacterins based on Yersinia ruckeri, serotype O1, biotypes 1 and 2) for rainbow trout (Oncorhynchus mykiss) were compared in order to evaluate whether the use of local pathogen strains for immunization can improve protection. In addition, the effect of the bacterin concentration was established for the commercial product. Following sublethal challenge of vaccinated and non-vaccinated control fish with live bacteria, we followed the bacterial count in the fish (gills, liver and spleen). The expression of genes encoding immune factors (IL-1β, IL-6, IL-8, IL-10, IFN-γ, MHCI, MHCII, CD4, CD8, TCRβ, IgM, IgT, IgD, cathelicidins 1 and 2, SAA and C3) and densities of immune cells in organs were recorded. Both vaccines conferred protection as judged from the reduced bacterial load in exposed fish. Innate immune genes were upregulated in all groups following bacterial challenge but significantly more in non-vaccinated naive fish in which densities of SAA-positive immune cells increased. Immunoglobulin genes were upregulated on day 5 post-challenge, and fish vaccinated with the high commercial bacterin dosage showed increased IgM levels by ELISA on day 14 post-challenge, reflecting that the vaccine dosage was correlated to protection. In conclusion, both vaccine types offered protection to rainbow trout when exposed to live Y. ruckeri and no significant difference between commercial and autogenous vaccines was established.

  • protective effect of in feed specific igm towards Yersinia ruckeri in rainbow trout
    Fish & Shellfish Immunology, 2019
    Co-Authors: Inger Dalsgaard, Jiwan Kumar Chettri, Kurt Buchmann, Azmi Aljubury, Marie Bendix Hansen, Allan Otto Fog Lihme, Peter M H Heegaard
    Abstract:

    Abstract Tightened regulations and an environmentally friendly approaches in fish production have greatly reduced the use of antibiotics but green solutions are continuously being explored. The use of functional feed may have a potential in the aquaculture sector in securing biomass and minimizing the loss from disease. In the present study, we tested the concept that blood from the fish slaughterhouse can be used for mass purification of specific antibodies which subsequently can be used for feeding fish and thereby confer protection against diseases. IgM was purified from serum from Yersinia ruckeri vaccinated rainbow trout and an IgM sandwich ELISA was developed for quantification of rainbow trout IgM. The purified IgM was encapsulated in alginate microparticles and top-coated in fish feed. IgM re-extracted from the alginate microparticles was shown to retain high reactivity towards Y. ruckeri antigens indicating that its bioactivity remained intact after encapsulation. IgM release from the alginate microparticles was only observed at high pH (pH 8.2) and minimal at low pH, indicating protection of IgM at low pH in the fish stomach during passage. In a feeding – challenge experiment (feeding 1 week before Y. ruckeri challenge and for two weeks following challenge), a statistically non-significant 10% lower mortality was observed in the high dose (400 μg IgM/fish/day fed over 3 weeks) group.

  • effects of soluble immunostimulants on mucosal immune responses in rainbow trout immersion vaccinated against Yersinia ruckeri
    Aquaculture, 2018
    Co-Authors: Jakob Skov, Inger Dalsgaard, Jiwan Kumar Chettri, Rzgar M Jaafar, Per W Kania, Kurt Buchmann
    Abstract:

    Abstract Immersion vaccination of rainbow trout against Yersinia ruckeri infection is an established method to prevent enteric red mouth disease (ERM) but the effect is inferior to injection vaccination and the duration of protection is limited to less than six months. Adjuvants in vaccines may in general elevate the immune response and the present work elucidates how ERM immersion vaccination of trout in combination with exposure to soluble adjuvants, Montanide™ IMS 1312 VG PR and β-glucan, affects immune reactions. The former adjuvant, when used alone, induced a slightly increased protection (not statistically significant) whereas β-glucan did not increase protection. Adjuvant-treated and non-exposed groups showed elevated plasma lysozyme activity after challenge with Y. ruckeri. Specific antibody production was not positively affected by combining adjuvant and vaccine. Overall expression of immune genes tested was generally manifold higher in gills compared to skin. Only genes encoding SAA and IL-17C1 were expressed at a higher level in skin. Dynamic differences between the gill and skin compartments were also recorded for genes encoding cytokines (TNF-α, IL-1β, IL-6, IL-10, IL-12, IL-17A/F2, IL-17C1, IL-17C2, IL-22), immunoglobulins (IgM, IgD, IgT), cell markers (CD8α, TCR-β) and acute phase reactants (SAA, lysozyme). These genes were upregulated 24 h post-vaccination in fish gills exposed to both vaccine-adjuvant combinations when compared to fish exposed to vaccine alone. After a few weeks no vaccine induced reaction was seen and after challenge with bacteria mainly unvaccinated fish responded. Adjuvants used in combination with immersion vaccine clearly influences immune reactions and may improve duration and protection but further potency tests should be performed.

  • effect of oral booster vaccination of rainbow trout against Yersinia ruckeri depends on type of primary immunization
    Fish & Shellfish Immunology, 2017
    Co-Authors: Rzgar M Jaafar, Inger Dalsgaard, Per W Kania, Azmi Aljubury, Asma Mohammadkarami, Kurt Buchmann
    Abstract:

    Abstract Vaccination of rainbow trout against Enteric Redmouth Disease (ERM) caused by Yersinia ruckeri can be successfully performed by administering vaccine (a bacterin consisting of formalin killed bacteria) by immersion, bath or injection. Booster immunization is known to increase the protection of fish already primed by one of these vaccination methods. Oral vaccination of trout (administering vaccine in feed) is an even more convenient way of presenting antigen to the fish but the effect of an oral booster has not previously been described in detail. The present work describes to what extent protection may be enhanced by oral boostering following priming with different administration methods. The study confirms that vaccination by 30 s dip into a bacterin (diluted 1:10) may confer a significant protection compared to non-vaccinated fish. The immunity may be optimized by booster immunization either provided as dip (most effective), bath (less effective) or orally (least effective). Oral immunization may be used as booster after dip but applied as a single oral application it induced merely a slight and statistically non-significant response. It is noteworthy that primary oral immunization followed by an oral booster vaccination showed a trend for an even weaker response. It should be investigated if continued exposure to a low antigen concentration – as performed by two oral immunizations - may induce tolerance to the pathogen and thereby leave the fish more vulnerable.

  • antimicrobial peptide cap18 and its effect on Yersinia ruckeri infections in rainbow trout oncorhynchus mykiss walbaum comparing administration by injection and oral routes
    Journal of Fish Diseases, 2017
    Co-Authors: Jiwan Kumar Chettri, Inger Dalsgaard, Foojan Mehrdana, Egon Bech Hansen, Anna Elisabeth Ebbensgaard, Michael Toft Overgaard, Anne Hjorngaard Lauritsen, Kurt Buchmann
    Abstract:

    The antimicrobial peptide CAP18 has been demonstrated to have a strong in vitro bactericidal effect on Yersinia ruckeri, but its activity in vivo has not been described. In this work, we investigated whether CAP18 protects rainbow trout Oncorhynchus mykiss (Walbaum) against enteric red mouth disease caused by this pathogen either following i.p. injection or by oral administration (in feed). It was found that injection of CAP18 into juvenile rainbow trout before exposure to Y. ruckeri was associated with lowered mortality compared to non-medicated fish although it was less effective than the conventional antibiotic oxolinic acid. Oral administration of CAP18 to trout did not prevent infection. The proteolytic effect of secretions on the peptide CAP18 in the fish gastrointestinal tract is suggested to account for the inferior effect of oral administration.

Jiwan Kumar Chettri - One of the best experts on this subject based on the ideXlab platform.

  • protective effect of in feed specific igm towards Yersinia ruckeri in rainbow trout
    Fish & Shellfish Immunology, 2019
    Co-Authors: Inger Dalsgaard, Jiwan Kumar Chettri, Kurt Buchmann, Azmi Aljubury, Marie Bendix Hansen, Allan Otto Fog Lihme, Peter M H Heegaard
    Abstract:

    Abstract Tightened regulations and an environmentally friendly approaches in fish production have greatly reduced the use of antibiotics but green solutions are continuously being explored. The use of functional feed may have a potential in the aquaculture sector in securing biomass and minimizing the loss from disease. In the present study, we tested the concept that blood from the fish slaughterhouse can be used for mass purification of specific antibodies which subsequently can be used for feeding fish and thereby confer protection against diseases. IgM was purified from serum from Yersinia ruckeri vaccinated rainbow trout and an IgM sandwich ELISA was developed for quantification of rainbow trout IgM. The purified IgM was encapsulated in alginate microparticles and top-coated in fish feed. IgM re-extracted from the alginate microparticles was shown to retain high reactivity towards Y. ruckeri antigens indicating that its bioactivity remained intact after encapsulation. IgM release from the alginate microparticles was only observed at high pH (pH 8.2) and minimal at low pH, indicating protection of IgM at low pH in the fish stomach during passage. In a feeding – challenge experiment (feeding 1 week before Y. ruckeri challenge and for two weeks following challenge), a statistically non-significant 10% lower mortality was observed in the high dose (400 μg IgM/fish/day fed over 3 weeks) group.

  • effects of soluble immunostimulants on mucosal immune responses in rainbow trout immersion vaccinated against Yersinia ruckeri
    Aquaculture, 2018
    Co-Authors: Jakob Skov, Inger Dalsgaard, Jiwan Kumar Chettri, Rzgar M Jaafar, Per W Kania, Kurt Buchmann
    Abstract:

    Abstract Immersion vaccination of rainbow trout against Yersinia ruckeri infection is an established method to prevent enteric red mouth disease (ERM) but the effect is inferior to injection vaccination and the duration of protection is limited to less than six months. Adjuvants in vaccines may in general elevate the immune response and the present work elucidates how ERM immersion vaccination of trout in combination with exposure to soluble adjuvants, Montanide™ IMS 1312 VG PR and β-glucan, affects immune reactions. The former adjuvant, when used alone, induced a slightly increased protection (not statistically significant) whereas β-glucan did not increase protection. Adjuvant-treated and non-exposed groups showed elevated plasma lysozyme activity after challenge with Y. ruckeri. Specific antibody production was not positively affected by combining adjuvant and vaccine. Overall expression of immune genes tested was generally manifold higher in gills compared to skin. Only genes encoding SAA and IL-17C1 were expressed at a higher level in skin. Dynamic differences between the gill and skin compartments were also recorded for genes encoding cytokines (TNF-α, IL-1β, IL-6, IL-10, IL-12, IL-17A/F2, IL-17C1, IL-17C2, IL-22), immunoglobulins (IgM, IgD, IgT), cell markers (CD8α, TCR-β) and acute phase reactants (SAA, lysozyme). These genes were upregulated 24 h post-vaccination in fish gills exposed to both vaccine-adjuvant combinations when compared to fish exposed to vaccine alone. After a few weeks no vaccine induced reaction was seen and after challenge with bacteria mainly unvaccinated fish responded. Adjuvants used in combination with immersion vaccine clearly influences immune reactions and may improve duration and protection but further potency tests should be performed.

  • antimicrobial peptide cap18 and its effect on Yersinia ruckeri infections in rainbow trout oncorhynchus mykiss walbaum comparing administration by injection and oral routes
    Journal of Fish Diseases, 2017
    Co-Authors: Jiwan Kumar Chettri, Inger Dalsgaard, Foojan Mehrdana, Egon Bech Hansen, Anna Elisabeth Ebbensgaard, Michael Toft Overgaard, Anne Hjorngaard Lauritsen, Kurt Buchmann
    Abstract:

    The antimicrobial peptide CAP18 has been demonstrated to have a strong in vitro bactericidal effect on Yersinia ruckeri, but its activity in vivo has not been described. In this work, we investigated whether CAP18 protects rainbow trout Oncorhynchus mykiss (Walbaum) against enteric red mouth disease caused by this pathogen either following i.p. injection or by oral administration (in feed). It was found that injection of CAP18 into juvenile rainbow trout before exposure to Y. ruckeri was associated with lowered mortality compared to non-medicated fish although it was less effective than the conventional antibiotic oxolinic acid. Oral administration of CAP18 to trout did not prevent infection. The proteolytic effect of secretions on the peptide CAP18 in the fish gastrointestinal tract is suggested to account for the inferior effect of oral administration.

  • oil adjuvant elevates protection of rainbow trout oncorhynchus mykiss following injection vaccination against Yersinia ruckeri
    Fish & Shellfish Immunology, 2016
    Co-Authors: Rzgar M Jaafar, Inger Dalsgaard, Jiwan Kumar Chettri, Jakob Skov, Per W Kania, Azmi Aljubury, Kurt Buchmann
    Abstract:

    Enteric redmouth disease (ERM) caused by the fish pathogen Yersinia ruckeri is a major threat to freshwater production of rainbow trout throughout all life stages. Injection vaccination of rainbow trout against Y. ruckeri infection has been shown to confer better protection compared to the traditionally applied immersion vaccination. It may be hypothesized, based on experience from other vaccines, that adjuvants may increase the protective level of ERM injection vaccines even more. Controlled comparative vaccination studies conducted to investigate effects of the oil adjuvant MontanideTM ISA 763 A VG when added to an experimental Y. ruckeri bacterin (containing both biotype 1 and 2 of serotype O1). A total of 1000 fish with mean weight 19 g was divided into five different groups (in duplicated tanks 2 × 100 fish per group) 1) nonvaccinated control fish (NonVac), 2) fish injected with a commercial vaccine (AquaVac ReleraTM) (ComVac), 3) fish injected with an experimental vaccine (ExpVac), 4) fish injected with an experimental vaccine + adjuvant (ExpVacAdj) and 5) fish injected with adjuvant alone (Adj). Injection of the experimental vaccine (both adjuvanted and non-adjuvanted) induced a significantly higher antibody (IgM) level, increased occurrence of IgM cells in spleen tissue and significant up-regulation of several immune genes. Additional experiments using a higher challenge dosage suggested an immune enhancing effect of the adjuvant as the challenge produced 100% mortality in the NonVac group, 60% mortality in both of ComVac and Adj groups and only 13 and 2.5% mortalities in the ExpVac and the ExpVacAdj groups, respectively.

  • effects of adjuvant montanide isa 763 a vg in rainbow trout injection vaccinated against Yersinia ruckeri
    Fish & Shellfish Immunology, 2015
    Co-Authors: Rzgar M Jaafar, Inger Dalsgaard, Jiwan Kumar Chettri, Jakob Skov, Per W Kania, Azmi Aljubury, Kurt Buchmann
    Abstract:

    Enteric redmouth disease (ERM) caused by the fish pathogen Yersinia ruckeri is a major threat to freshwater production of rainbow trout (Oncorhynchus mykiss) throughout all life stages. Injection vaccination of rainbow trout against Y. ruckeri infection has been shown to confer better protection compared to the traditionally applied immersion vaccination. It may be hypothesized, based on experience from other vaccines, that adjuvants may increase the protective level of ERM injection vaccines even more. Controlled comparative vaccination studies have been performed to investigate effects of the oil adjuvant Montanide™ ISA 763 A VG (Seppic) when added to an experimental Y. ruckeri bacterin (containing both biotype 1 and 2 of serotype O1). A total of 1000 fish with mean weight 19 g was divided into five different groups (in duplicated tanks 2 × 100 fish per group) 1) non-vaccinated control fish (NonVac), 2) fish injected with a commercial vaccine (AquaVac(®) Relera™) (ComVac), 3) fish injected with an experimental vaccine (ExpVac), 4) fish injected with an experimental vaccine + adjuvant (ExpVacAdj) and 5) fish injected with adjuvant alone (Adj). Injection of the experimental vaccine (both adjuvanted and non-adjuvanted) induced a significantly higher antibody (IgM) level, increased occurrence of IgM(+) cells in spleen tissue and significant up-regulation of several immune genes. Additional experiments using a higher challenge dosage suggested an immune enhancing effect of the adjuvant as the challenge produced 100% mortality in the NonVac group, 60% mortality in both of ComVac and Adj groups and only 13 and 2.5% mortalities in the ExpVac and the ExpVacAdj groups, respectively.

Timothy J. Welch - One of the best experts on this subject based on the ideXlab platform.

  • characterization of a novel Yersinia ruckeri serotype o1 specific bacteriophage with virulence neutralizing activity
    Journal of Fish Diseases, 2020
    Co-Authors: Timothy J. Welch
    Abstract:

    A lytic bacteriophage (φNC10) specific to serotype O1 Yersinia ruckeri has been identified and evaluated as a model to assess the potential use of bacteriophages and their products for disease control in aquaculture. Electron microscopy of purified φNC10 revealed a virion particle with a small (70 nm) polyhedral head and short tail. φNC10 infected only serotype O1 strains of Y. ruckeri and failed to bind a defined Y. ruckeri mutant strain lacking O1 lipopolysaccharides (O1-LPS), suggesting that φNC10 uses O1-LPS as its receptor. In addition, spontaneous φNC10-resistant mutants of Y. ruckeri exhibited defects in O1-LPS production and were sensitive to rainbow trout serum. Purified φNC10 displayed a polysaccharide depolymerase activity capable of degrading Y. ruckeri O1-LPS and thereby sensitizing Y. ruckeri to the bactericidal effects of rainbow trout serum. The φNC10-associated polysaccharide depolymerase activity also reduced the ability of Y. ruckeri cells to cause mortality following intraperitoneal injection into rainbow trout. These data demonstrate a potential utility of φNC10 and its associated polysaccharide depolymerase activity for Y. ruckeri disease prevention.

  • proteome analysis reveals a role of rainbow trout lymphoid organs during Yersinia ruckeri infection process
    Scientific Reports, 2018
    Co-Authors: Gokhlesh Kumar, Karin Hummel, Timothy J. Welch, Katharina Noebauer, Ebrahim Razzazifazeli, Mansour Elmatbouli
    Abstract:

    Yersinia ruckeri is the causative agent of enteric redmouth disease in salmonids. Head kidney and spleen are major lymphoid organs of the teleost fish where antigen presentation and immune defense against microbes take place. We investigated proteome alteration in head kidney and spleen of the rainbow trout following Y. ruckeri strains infection. Organs were analyzed after 3, 9 and 28 days post exposure with a shotgun proteomic approach. GO annotation and protein-protein interaction were predicted using bioinformatic tools. Thirty four proteins from head kidney and 85 proteins from spleen were found to be differentially expressed in rainbow trout during the Y. ruckeri infection process. These included lysosomal, antioxidant, metalloproteinase, cytoskeleton, tetraspanin, cathepsin B and c-type lectin receptor proteins. The findings of this study regarding the immune response at the protein level offer new insight into the systemic response to Y. ruckeri infection in rainbow trout. This proteomic data facilitate a better understanding of host-pathogen interactions and response of fish against Y. ruckeri biotype 1 and 2 strains. Protein-protein interaction analysis predicts carbon metabolism, ribosome and phagosome pathways in spleen of infected fish, which might be useful in understanding biological processes and further studies in the direction of pathways.

  • multilocus variable number tandem repeat analysis of Yersinia ruckeri confirms the existence of host specificity geographic endemism and anthropogenic dissemination of virulent clones
    Applied and Environmental Microbiology, 2018
    Co-Authors: Snorre Gulla, Timothy J. Welch, David W Vernerjeffreys, Jesus L Romalde, Michael J Ormsby, Andrew J Barnes, David Ryder, Jeremy Carson, Karin Lagesen, Robert L Davies
    Abstract:

    A Multi-Locus Variable number of tandem repeat Analysis (MLVA) assay was developed for epizootiological study of the internationally significant fish pathogen Yersinia ruckeri , which causes yersiniosis in salmonids. The assay involves amplification of ten Variable Number of Tandem Repeat (VNTR) loci in two five-plex PCR reactions, followed by capillary electrophoresis. A collection of 484 Y. ruckeri isolates, originating from various biological sources and collected from four continents over seven decades, was analysed. Minimum spanning tree cluster analysis of MLVA profiles separated the studied population into nine major clonal complexes, and a number of minor clusters and singletons. The major clonal complexes could be associated with host species, geographic origin and serotype. A single large clonal complex of serotype O1 isolates dominating the yersiniosis situation in international rainbow trout farming suggests anthropogenic spread of this clone, possibly related to transport of fish. Moreover, sub-clustering within this clonal complex indicates putative transmission routes and multiple biotype shift events. In contrast to the situation in rainbow trout, Y. ruckeri strains associated with disease in Atlantic salmon appear as more or less geographically isolated clonal complexes. A single complex of serotype O1 exclusive to Norway was found to be responsible for almost all major yersiniosis outbreaks in modern Norwegian salmon farming, and site-specific sub-clustering further indicates persistent colonisation of freshwater farms in Norway. Identification of genetically diverse Y. ruckeri isolates from clinically healthy fish and environmental sources also suggests the widespread existence of less virulent or avirulent strains. Importance This comprehensive population study substantially improves our understanding of the epizootiological history and nature of an internationally important fish pathogenic bacterium. The MLVA assay developed and presented represents a high-resolution typing tool particularly well suited for Yersinia ruckeri infection tracing, selection of strains for vaccine inclusion, and risk assessment. The ability of the assay to separate isolates into geographically linked and/or possibly host-specific clusters reflects its potential utility for maintenance of national biosecurity. The MLVA is internationally applicable, robust, and provides clear, unambiguous and easily interpreted results. Typing is reasonably inexpensive, with a moderate technological requirement, and may be completed from a harvested colony within a single working day. As the resulting MLVA profiles are readily portable, any Y. ruckeri strain may rapidly be placed in a global epizootiological context.

  • the flagellar master operon flhdc is a pleiotropic regulator involved in motility and virulence of the fish pathogen Yersinia ruckeri
    Journal of Applied Microbiology, 2017
    Co-Authors: Anna K S Jozwick, Joerg Graf, Timothy J. Welch
    Abstract:

    Aims To investigate the function of the master flagellar operon flhDC in the fish pathogen Yersinia ruckeri and compare the effect of a constructed flhD mutation to a naturally occurring fliR mutation causing loss-of-motility in emergent biotype 2 (BT2) strains. Methods and Results Yersinia ruckeri flhD and fliR mutants were constructed in a motile strain. Both mutations caused loss-of-motility, ablation of flagellin synthesis and phospholipase secretion, similar to naturally occurring BT2 strains. Transcriptome analysis confirmed flhDC regulation of flagellar, chemotaxis and phospholipase loci as well as other genes of diverse function. The flhD mutation confers a competitive advantage within the fish host when compared with its parent strain, while this advantage was not seen with the naturally occurring fliR mutation. Conclusions An intact flhD is necessary for expression of the flagellar secretion system as well as other diverse loci, consistent with a role for flhD as a pleiotropic regulator. The maintenance of the flhD locus in Y. ruckeri strains suggests its importance for aspects of Y. ruckeri biology other than virulence, since the flhD mutation conferred a competitive advantage during experimental challenge of rainbow trout. Significance and Impact of the Study Yersinia ruckeri is the causative agent of enteric red mouth disease, an invasive septicaemia that affects farmed salmonid fish species. Disease outbreaks can cause severe economic losses in aquaculture. BT2 variants, which have independently emerged worldwide, are an increasing threat to farmed fish production. Knowledge of mechanisms involved in virulence, conserved functions and gene regulation among strains may be exploited for the development of novel disease control strategies to prevent pathogen growth or virulence phenotypes within aquaculture.

  • Global proteomic profiling of Yersinia ruckeri strains
    BMC, 2017
    Co-Authors: Gokhlesh Kumar, Karin Hummel, Timothy J. Welch, Ebrahim Razzazi-fazeli, Mansour El-matbouli
    Abstract:

    Abstract Yersinia ruckeri is the causative agent of enteric redmouth disease (ERM) of salmonids. There is little information regarding the proteomics of Y. ruckeri. Herein, we perform whole protein identification and quantification of biotype 1 and biotype 2 strains of Y. ruckeri grown under standard culture conditions using a shotgun proteomic approach. Proteins were extracted, digested and peptides were separated by a nano liquid chromatography system and analyzed with a high-resolution hybrid triple quadrupole time of flight mass spectrometer coupled via a nano ESI interface. SWATH-MS technology and sophisticated statistical analyses were used to identify proteome differences among virulent and avirulent strains. GO annotation, subcellular localization, virulence proteins and antibiotic resistance ontology were predicted using bioinformatic tools. A total of 1395 proteins were identified in the whole cell of Y. ruckeri. These included proteases, chaperones, cell division proteins, outer membrane proteins, lipoproteins, receptors, ion binding proteins, transporters and catalytic proteins. In virulent strains, a total of 16 proteins were upregulated including anti-sigma regulatory factor, arginine deiminase, phosphate-binding protein PstS and superoxide dismutase Cu–Zu. Additionally, several virulence proteins were predicted such as Clp and Lon pro-teases, TolB, PPIases, PstS, PhoP and LuxR family transcriptional regulators. These putative virulence proteins might be used for development of novel targets for treatment of ERM in fish. Our study represents one of the first global proteomic reference profiles of Y. ruckeri and this data can be accessed via ProteomeXchange with identifier PXD005439. These proteomic profiles elucidate proteomic mechanisms, pathogenicity, host-interactions, antibiotic resistance ontology and localization of Y. ruckeri proteins