枯草芽孢杆菌无细胞上清液抑制单增李斯特菌生物被膜形成的研究OA北大核心CSTPCD

Listeria monocytogenes is a common foodborne pathogen,and its biofilm is an important cause of food contamination and disease transmission.In this study,the cell free supernatant(CFS)of Bacillus subtilis was selected as an inhibitor to explore the role and potential of B.subtilis CFS in inhibiting L.monocytogenes 118(No.118 for short)biofilm.Firstly,the minimum inhibitory concentration(MIC)of B.subtilis CFS was determined,and then the biofilm inhibition rate of B.subtilis CFS to No.118 was determined by using crys-tal violet staining method.Results showed that CFS at different sub-MICs had a significant inhibitory effect on No.118 biofilm,and the biofilm inhibition rate could still reach 47％at 1/64 MIC.Meanwhile,B.subtilis CFS also significantly inhibited the metabolic activity,self-aggregation rate,surface hydrophobicity,swaming and extramembrane polymer secretion of No.118 biofilm cells.Finally,the changes of No.118 biofilm structure and cell distribution under the action of CFS were observed by confocal laser scanning microscope.After CFS treatment,the structure of No.118 biofilm was loose,and the number of bacteria was significantly reduced.Consequently,this study found that B.subtilis CFS can inhibit the biofilm formation of No.118 biofilm cells by affecting their metabolic activity,self-aggregation ability and swaming,as well as the secretion of extramembrane polymers.This has important reference value for exploring the application of probi-otic metabolites as biofilm inhibitors.