INFLUENCE OF SALINITY AND PH ON THE ADHESION OF PATHOGENIC VIBRIO STRAINS TO SPARUS-AURATA SKIN MUCUS

It is generally known that adhesion of bacteria to mucosal surfaces is an initial step for many microbial infections. Nevertheless, the role played by the mucus layer of fish, especially that of Sparus aurata, during colonization of fish skin by saprophytic and pathogenic bacteria has not been established yet, In this work, the influence of salinity and pH on the adhesion abilities of Vibrio strains isolated from diseased fish to S. aurata skin mucus has been studied, Forty percent of the 30 strains tested attached to mucus-coated glass slides. Attachment was directly related to the ability of the strains to form pellicle in broth, but not to the degree of hydrophobicity of the strains. The highest adhesion rate was achieved with seawater (3.5% salinity) and glass slides coated with mucus solutions with a pH range of 8.2-8.5. The results obtained indicate that seawater and mucus at the normal pH of seawater (pH 8.1) were the most appropriate conditions for the attachment of pathogenic Vibrio strains to S. aurata skin mucus.