Chemotaxis of Vibrio anguillarum to fish mucus: role of the origin of the fish mucus, the fish species and the serogroup of the pathogen

The port of entrance in the fish for the pathogenic bacterium Vibrio anguillarum remains an enigma. Chemotactic motility has previously been shown to be a virulence factor, and chemotactic responses to mucus from different parts of the body might differ depending on the preferred port. In the present study, V. anguillarum was highly chemotactic to fish mucus from gills, skin and intestine of rainbow trout (Oncorhynchus mykiss L.) and significantly more chemotactic to skin and intestinal mucus than gill mucus. Strains of V. anguillarum show some degree of host preference. However, serogroup O1 strains (most commonly isolated from salmonids) and serogroup O2 strains (commonly isolated from cod) were all chemotactic to mucus from the skin of rainbow trout, cod, common bream, and flounder. An avirulent strain of V. anguillarum was as chemotactic as the virulent strains.