Fate of pre-formed Vibrio parahaemolyticus biofilm under cold shock

Abstract:

[Objective] The aim of the study was to analyze changes of pre-formed Vibrio parahaemolyticus biofilm under cold shock. The source of persistent infections can be biofilms that occur naturally on food surfaces and medical biomaterials. The change of pre-formed Vibrio parahaemolyticus biofilm under cold shock was studied.[Methods] The changes of biofilm biomass were checked by crystal violet staining, exopolysaccharides and proteins were quantified by modified sonication method and Lowry method, and genes related to the expression of biofilm were extracted and purified by RNA extraction kit. The Confocal laser scanning microscopy (CLSM) images reveal biofilm morphological structure, the correlation analysis shows inner relationship among biofilm structure parameters and biofilm related genes.[Results] V. parahaemolyticus biofilm biomass increased significantly during this cold shock period. Polysaccharides and proteins increased gradually in the extracellular polymeric matrix (EPS). In addition, the expression of flagella and virulence-related genes were differentially regulated. The architecture of the biofilm, quantified using mean thickness, average diffusion distance, porosity, biofilm roughness and homogeneity also changed during the cold shock and these parameters were correlated (P < 0.01). However, the correlation between biofilm architecture and biofilm-related gene expression was relatively weak (P<0.05). [Conclusion] Cold shock at 4℃ and 10℃ is not sufficient to reduce V. parahaemolyticus biofilm formation.