Identification of a Ribosomal L10-Like Protein from Flavobacterium psychrophilum as a Recombinant Vaccine Candidate for Rainbow Trout Fry Syndrome

2007 ◽  
Vol 13 (1-3) ◽  
pp. 55-64 ◽  
Author(s):  
Elizabeth M. Crump ◽  
Ján Burian ◽  
Philippe D. Allen ◽  
Stephen Gale ◽  
William W. Kay
Microbiology ◽  
2005 ◽  
Vol 151 (9) ◽  
pp. 3127-3135 ◽  
Author(s):  
Elizabeth M. Crump ◽  
Ján Burian ◽  
Philippe D. Allen ◽  
William W. Kay

Flavobacterium psychrophilum is the aetiological agent of rainbow trout fry syndrome, an economically important disease of immature salmonid fish for which there is no vaccine. Convalescent serum from the host, rainbow trout (Oncorhynchus mykiss), reacted strongly with a ∼20 kDa, Flavobacterium-specific protein antigen (subsequently named FspA) from F. psychrophilum. Protein-enriched, detergent-partitioned samples were separated by two-dimensional gel electrophoresis and the protein target was excised, proteolytically cleaved and the resulting peptides analysed by MS. Quadrupole-time-of-flight MS was used to generate a fragmented peptide spectrum. The resulting peptide sequences were then used to design degenerate PCR primers to amplify the gene (fspA) of interest: 612 bp encoding 203 aa, including a putative 19 aa N-terminal signal sequence which predicted a processed 19 303·6 Da protein. FspA proved to be unique and only homologous to two unspecified sequences reported from Flavobacterium johnsoniae, although weakly homologous to a Yersinia pseudotuberculosis adhesin. An amplified gene fragment (537 bp, encoding 179 aa) was further cloned into an expression vector, expressed as a ∼30 kDa N-terminal fusion protein and found to retain its strong reactivity with host serum antibodies. These results suggest that the surface-localized FspA may be an important subunit vaccine candidate antigen against F. psychrophilum.


2019 ◽  
Vol 85 (6) ◽  
Author(s):  
Christopher Knupp ◽  
Gregory D. Wiens ◽  
Mohamed Faisal ◽  
Douglas R. Call ◽  
Kenneth D. Cain ◽  
...  

ABSTRACTFlavobacterium psychrophilum, the etiological agent of bacterial coldwater disease (BCWD) and rainbow trout fry syndrome (RTFS), causes significant economic losses in salmonid aquaculture, particularly in rainbow trout (Oncorhynchus mykiss). Prior studies have used multilocus sequence typing (MLST) to examine genetic heterogeneity withinF. psychrophilum. At present, however, its population structure in North America is incompletely understood, as only 107 isolates have been genotyped. Herein, MLST was used to investigate the genetic diversity of an additional 314 North AmericanF. psychrophilumisolates that were recovered from ten fish host species from 20 U.S. states and 1 Canadian province over nearly four decades. These isolates were placed into 66 sequence types (STs), 47 of which were novel, increasing the number of clonal complexes (CCs) in North America from 7 to 12. Newly identified CCs were diverse in terms of host association, distribution, and association with disease. The largestF. psychrophilumCC identified was CC-ST10, within which 10 novel genotypes were discovered, most of which came fromO. mykissexperiencing BCWD. This discovery, among others, provides evidence for the hypothesis that ST10 (i.e., the founding ST of CC-ST10) originated in North America. Furthermore, ST275 (in CC-ST10) was recovered from wild/feral adult steelhead and marks the first recovery of CC-ST10 from wild/feral fish in North America. Analyses also revealed that at the allele level, the diversification ofF. psychrophilumin North America is driven three times more frequently by recombination than random nucleic acid mutation, possibly indicating how new phenotypes emerge within this species.IMPORTANCEFlavobacterium psychrophilumis the causative agent of bacterial coldwater disease (BCWD) and rainbow trout fry syndrome (RTFS), both of which cause substantial losses in farmed fish populations worldwide. To better prevent and control BCWD and RTFS outbreaks, we sought to characterize the genetic diversity of several hundredF. psychrophilumisolates that were recovered from diseased fish across North America. Results highlighted multipleF. psychrophilumgenetic strains that appear to play an important role in disease events in North American aquaculture facilities and suggest that the practice of trading fish eggs has led to the continental and transcontinental spread of this bacterium. The knowledge generated herein will be invaluable toward guiding the development of future disease prevention techniques.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mio Takeuchi ◽  
Erina Fujiwara-Nagata ◽  
Taiki Katayama ◽  
Hiroaki Suetake

AbstractRainbow trout fry syndrome (RTFS) and bacterial coldwater disease (BCWD) is a globally distributed freshwater fish disease caused by Flavobacterium psychrophilum. In spite of its importance, an effective vaccine is not still available. Manipulation of the microbiome of skin, which is a primary infection gate for pathogens, could be a novel countermeasure. For example, increasing the abundance of specific antagonistic bacteria against pathogens in fish skin might be effective to prevent fish disease. Here, we combined cultivation with 16S rRNA gene amplicon sequencing to obtain insight into the skin microbiome of the rainbow trout (Oncorhynchus mykiss) and searched for skin bacteria antagonistic to F. psychrophilum. By using multiple culture media, we obtained 174 isolates spanning 18 genera. Among them, Bosea sp. OX14 and Flavobacterium sp. GL7 respectively inhibited the growth of F. psychrophilum KU190628-78 and NCIMB 1947T, and produced antagonistic compounds of < 3 kDa in size. Sequences related to our isolates comprised 4.95% of skin microbial communities, and those related to strains OX14 and GL7 respectively comprised 1.60% and 0.17% of the skin microbiome. Comparisons with previously published microbiome data detected sequences related to strains OX14 and GL7 in skin of other rainbow trout and Atlantic salmon.


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