Abstract:Yersinia enterocolitica is a gram-negative foodborne pathogen that can form biofilms on the surfaces of food and food processing equipment. Biofilms can enhance strain viability and affect food safety. In this study, Y. enterocolitica strain C1967-1 isolated from quick-frozen food, which has a strong ability to form biofilms, was evaluated. Proteomics analysis was used to analyze the differences in protein expression between the biofilms and planktonic bacteria. Gene Ontology (GO) enrichment analysis demonstrated that, among the top nine GO categories with the highest degree of enrichment, seven showed downregulation trends in biofilms. Only GO:0046873 (metal ion transmembrane transporter activity) did not show significant upregulation or downregulation trends in biofilms. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment results suggested that the top 20 KEGG pathways with the highest degree of enrichment mainly involved metabolism of carbohydrates, amino acids, and lipids. The subcellular localization analysis results revealed that 45.65% of differential proteins were located in the cytoplasm. The upregulated protein MgtA of the biofilm was selected from GO:0046873, and the gene mgtA was knocked out to further verify the proteomics data. The results indicated that the knockout of mgtA did not inhibit strain growth. However, the biofilm amount of ΔmgtA was reduced by approximately 80%, and the structure of the biofilm was loosened. In summary, these results provide an important theoretical basis for the biofilm formation mechanism of Y. enterocolitica and the prevention of bacterial biofilm formation in the food industry.
