417
ing in an immune response (in the skin) two weeks later, and survival of 60 % and
20 %, respectively (Mano et al. 1996 ). Interestingly, 14 days following vaccination
by immersion and injection of eel with formalin killed cells of Fla. columnare
agglutinating antibody could not be detected in the serum or mucus. Instead, there
was inhibition of bacterial adhesion in the skin of the immersion vaccinated eel
(Mano et al. 1996 ). Formalin-inactivated sonicated and whole cell preparations of
Fla. columnare were applied intraperitoneally and by immersion to tilapia with
booster doses after 4 weeks (Grabowski et al. 2004 ). The data revealed that use of
formalised sonicated cells in FCA injected by i.p. led to a signifi cant humoral
immune response (titre = 1: 11,200 by ELISA after 2 weeks; titre = 1:30,600 after
boosting). However, there was no information about protection. It has been suggested that rifampicin mutants of high virulence strains may well become vaccine
candidates (Olivares-Fuster and Arias 2011 ).
A modifi ed live Fla. columnare vaccine and a 1:1 bivalent product with a commercial vaccine for Edw. ictaluri was evaluated in channel catfi sh eggs. The live
vaccine was administered by immersion (1.35 × 10
7 CFU/ml for 15 min) with a
booster on day 34 (2.17 × 10
7 CFU/ml for 15 min) leading to RPS values of
50–76.8 % after challenge. Similarly, the bivalent product was applied by immersion for 15 min, and challenged with RPS of 33–59.7 %. Overall, the approach was
successful in protecting fi sh from the eyed egg stage against challenge with Fla.
columnare (Shoemaker et al. 2007 ). Avirulent mutants derived from genomovar I
and the more virulent genomovar II were administered to channel catfi sh fry and
Nile tilapia, with the results pointing to protection with both genomovar mutants
(Mohammed et al. 2013 ).
Another approach to developing vaccines could be to determine which components of the pathogen stimulate immune responses. By use of two-dimensional electrophoresis immunoblotting of antiserum from grass carp, Liu et al. ( 2012 ) reported
that 14 proteins of Fla. columnare were immunogenic, and included alcohol dehydrogenase, dihydrolipoamide succinyltransferase, fructose-biphosphate aldolase,
3-hydroxybutyryl-CoA dehydrogenase, regulator protein, 30S ribosomal subunit
protein S1, succinyl-CoA synthetase, SpoOJ, translation elongation factors G and
Tu, two conserved hypothetical proteins, and chaperonins DnaK, GroEL and trigger
factor. The suggestion was made that some among these bacterial proteins would be
appropriate candidates for vaccine development (Liu et al. 2012 ).
A ghost vaccine was produced involving a specifi c Flavobacterium lysis plasmid
pBV-E-cat that was electroporated into Fla. columnare G4cpN22 after curing of its
endogenous plasmid. The ghosts were by gene E-mediated lysis, and administered
by i.p. injection to grass carp ( Ctenopharyngodon idellus ) leading after challenge to
a RPS of 70.9 % (Zhu et al. 2012 ).
Probiotics/Biocontrol The progress of infection of Fla. columnare was mediated
by Aer. hydrophila and Cit. freundii (Chowdbury and Wakabayashi 1989 ).
Subsequently, Boutin et al. ( 2012 ) recovered bacteria from the skin of brook charr
that were inhibitory in vitro to Fla. columnaris, and when mixed and administered
to fi sh led to a decrease in mortality after challenge.
Flavobacterium columnare (=Flexibacter/Cytophaga columnaris)
ing in an immune response (in the skin) two weeks later, and survival of 60 % and
20 %, respectively (Mano et al. 1996 ). Interestingly, 14 days following vaccination
by immersion and injection of eel with formalin killed cells of Fla. columnare
agglutinating antibody could not be detected in the serum or mucus. Instead, there
was inhibition of bacterial adhesion in the skin of the immersion vaccinated eel
(Mano et al. 1996 ). Formalin-inactivated sonicated and whole cell preparations of
Fla. columnare were applied intraperitoneally and by immersion to tilapia with
booster doses after 4 weeks (Grabowski et al. 2004 ). The data revealed that use of
formalised sonicated cells in FCA injected by i.p. led to a signifi cant humoral
immune response (titre = 1: 11,200 by ELISA after 2 weeks; titre = 1:30,600 after
boosting). However, there was no information about protection. It has been suggested that rifampicin mutants of high virulence strains may well become vaccine
candidates (Olivares-Fuster and Arias 2011 ).
A modifi ed live Fla. columnare vaccine and a 1:1 bivalent product with a commercial vaccine for Edw. ictaluri was evaluated in channel catfi sh eggs. The live
vaccine was administered by immersion (1.35 × 10
7 CFU/ml for 15 min) with a
booster on day 34 (2.17 × 10
7 CFU/ml for 15 min) leading to RPS values of
50–76.8 % after challenge. Similarly, the bivalent product was applied by immersion for 15 min, and challenged with RPS of 33–59.7 %. Overall, the approach was
successful in protecting fi sh from the eyed egg stage against challenge with Fla.
columnare (Shoemaker et al. 2007 ). Avirulent mutants derived from genomovar I
and the more virulent genomovar II were administered to channel catfi sh fry and
Nile tilapia, with the results pointing to protection with both genomovar mutants
(Mohammed et al. 2013 ).
Another approach to developing vaccines could be to determine which components of the pathogen stimulate immune responses. By use of two-dimensional electrophoresis immunoblotting of antiserum from grass carp, Liu et al. ( 2012 ) reported
that 14 proteins of Fla. columnare were immunogenic, and included alcohol dehydrogenase, dihydrolipoamide succinyltransferase, fructose-biphosphate aldolase,
3-hydroxybutyryl-CoA dehydrogenase, regulator protein, 30S ribosomal subunit
protein S1, succinyl-CoA synthetase, SpoOJ, translation elongation factors G and
Tu, two conserved hypothetical proteins, and chaperonins DnaK, GroEL and trigger
factor. The suggestion was made that some among these bacterial proteins would be
appropriate candidates for vaccine development (Liu et al. 2012 ).
A ghost vaccine was produced involving a specifi c Flavobacterium lysis plasmid
pBV-E-cat that was electroporated into Fla. columnare G4cpN22 after curing of its
endogenous plasmid. The ghosts were by gene E-mediated lysis, and administered
by i.p. injection to grass carp ( Ctenopharyngodon idellus ) leading after challenge to
a RPS of 70.9 % (Zhu et al. 2012 ).
Probiotics/Biocontrol The progress of infection of Fla. columnare was mediated
by Aer. hydrophila and Cit. freundii (Chowdbury and Wakabayashi 1989 ).
Subsequently, Boutin et al. ( 2012 ) recovered bacteria from the skin of brook charr
that were inhibitory in vitro to Fla. columnaris, and when mixed and administered
to fi sh led to a decrease in mortality after challenge.
Flavobacterium columnare (=Flexibacter/Cytophaga columnaris)