Adhesion of Vibrio fluvialis to the skin mucus of flounder, Paralichthys olivaceus

Bacterial adhesion to fish mucus is an important step in the initial stage of infection.It is important to underst and the characteristics involved in the adherence of bacteria to fish mucus so that preventive measures can be devised to reduce infection.In order to get a better understanding of adhesion characteristic of pathogenic Vibrio fluvialis to the skin mucus of Paralichthys olivaceus,the influences of bacterial density,incubation time,incubation temperature,pH,cation,and carbohydrate on the bacterial adhesion were investigated by using ³H-TdR as isotope tracer.The results showed that:the adhesive quantity of V.fluvialis increased with bacterial densities,a saturation kinetics hyperbola:y= 417.89ln(x)+691.57 (R²=0.986),was obtained by plotting adhered bacteria against the density of bacteria added;adhesive quantity of V.fluvialis increased with incubation times and reached equilibrium after incubation for 180 min;bacterial adhesion enhanced with the increase of incubation temperatures (from 4 to 30) and NaCl concentrations (from 0.5% to 4.5%);V.fluvialis exhibited stronger adhesion under sourish condition,strongest adhesion was recorded at pH 5;Ca²⁺ and Mg²⁺ obviously promoted the bacterial adhesion respectively,Ca²⁺ more efficiently;8 kinds of carbohydrates tested promoted the bacterial adhesion remarkably.The results indicated that:pathogenic V.fluvialis could adhere to the skin mucus of P.olivaceus facility,which would convenient for the subsequently infection;the bacterial adhesion was environmental factors dependent,warm water facilitated the bacterial adhesion.The results also indicated that the bacterial adhesion of V.fluvialis was governable,which might be useful for the vibriosis control in fish culture.