Influence of water quality and temperature on adhesion of high and low virulence Flavobacterium columnare strains to isolated gill arches

The ability of Flavobacterium columnare (Flexibacter columnaris) to attach to the gills of common carp, Cyprinus carpio L., was evaluated using a gill perfusion model. A comparison between a high and a low virulence strain of F. columnare was made and evaluated in comparison to results obtained prev iously with an in vivo model. The ion composition of the water of the organ bath in which the gills were suspended was varied and the influence on adh esion processes assessed. Experiments were carried out to examine the influ ence of water quality (i.e. nitrite and organic matter) and temperature on the capacity of the bacteria to adhere. It was found that the high virulenc e strain adhered more readily than the low virulence strain, as was found d uring the in vivo experiments. Moreover, it was observed that adhesion of t he high virulence strain was enhanced by a number of factors. These were im mersion of the gill in bivalent, ion-rich water, the presence of nitrite or organic matter, and high temperatures.