Characteristics of biofilm formation of pathogenic Vibrio anguillarum

Abstract:

[Background] Vibrio anguillarum is the main pathogen of marine animal vibriosis, which exists widely in seawater. It can form biofilm to adapt to environmental changes and form self-protection, the prevention and treatment of Vibrio anguillarum is a major challenge to aquaculture industry. [Objective] To study the characteristics of biofilm formation of pathogenic Vibrio anguillarum BYK0638, and to provide a reference for further study on the mechanism and pathogenesis of biofilm formation of V. anguillarum. [Methods] The characteristics of biofilm formation of V. anguillarum BYK0638 were studied by modified microtiter-plate test, and the viability of V. anguillarum in the biofilms was detected by CCK-8. [Results] V. anguillarum BYK0638 developed stable and evident biofilm on the surface of the polystyrene microtiter plate. OD450 value of V. anguillarum biofilm reached the peak after 24 h and stabilized after 60 h. Within the 107?108 CFU/mL, OD450 vaule of biofilm was significantly higher than the others (P<0.05). OD450 value of biofilm recorded at 25 °C was significantly higher than those recorded at other temperatures (P<0.05). In the range of pH 4.0?11.0, when pH value is 7.0, the amounts of bacterial biofilm was the highest, and at pH 3.0 and 12.0, no evident biofilm was found. Biofilm formation of V. anguillarum played no significant role when 0.03 to 2.00 mmol/L CaCl2 was added. Addition of 0.03% MgCl2 significantly promoted the bacterial biofilm formation while CaCl2 played no significantly role. At 5% NaCl, the OD450 value of biofilm was the highest. The biofilms developed on the surface of the microtiter plate coated by the skin mucus, liver, foregut and hindgut tissue extract of large yellow croaker was significantly higher than the others (P<0.05). [Conclusion] Pathogenic V. anguillarum BYK0638 can develop stable and obvious biofilm. The biofilm formation is closely related to the change of environmental factors, pH, temperature, Mg2+, salinity and other environmental factors can significantly affect the formation of biofilm of V. anguillarum.

Key words:Vibrio anguillarum, Biofilm, Environmental factors