乳酸菌细菌素plantaricin YKX对大肠杆菌生物被膜的抑制作用

Inhibitory Effect of Plantaricin YKX on the Biofilm of Escherichia coli

大肠杆菌作为最主要的食源性致病菌之一,可形成生物被膜,增加环境抗性,造成食源性疾病。本文研究实验室前期筛选、制备所得乳酸菌细菌素plantaricin YKX对大肠杆菌ATCC25922生物被膜的抑制作用。结晶紫染色试验结果显示:plantaricin YKX质量浓度增到3/4MIC时,大肠杆菌ATCC25922生物被膜形成抑制率在50%以上。菌落计数试验结果表明亚抑菌浓度的plantaricin YKX能够减少生物被膜中的活菌数。扫描电镜观察发现经plantaricin YKX处理的大肠杆菌生物被膜分布稀疏,结构遭到破坏。激光共聚焦显微镜观察经plantaricin YKX处理的大肠杆菌ATCC25922的生物被膜,发现其活菌数量明显比未经plantaricin YKX处理的少。采用荧光染料标记结合荧光显微镜观察plantaricin YKX对生物被膜多糖黏附的影响,结果显示,与1/2MIC plantaricin YKX共培养的大肠杆菌ATCC25922胞外多糖分泌减少。本研究为食源致病菌大肠杆菌控制提供新方法、新途径。

Escherichia coli,one of the most important foodborne pathogens,was able to form biofilms to increase the environmental resistance and cause foodborne diseases.The purpose of this study was to investigate the inhibitory effect and it mechanism of the bacteriocin plantaricin YKX on the biofilm of E.coli ATCC25922.The results of crystal violet staining suggested that the treatment with 3/4 MIC plantaricin YKX made inhibition rate of E.coli ATCC25922 biofilm to reach more than 50%.The plate count experiment also indicated that the subconcentration of plantaricin YKX could reduce the number of viable bacteria in the biofilm.Scanning electron microscopy(SEM)indicated that the E.coli ATCC25922 biofilms treated with plantaricin YKX were sparsely distributed and their structures were destroyed.The biofilm of E.coli ATCC25922 treated with plantaricin YKX was observed by laser confocal microscopy.The number of viable bacteria was significantly less than that of the one without plantaricin YKX.When co-cultured with 1/2MIC plantaricin YKX,the extracellular polysaccharide secretion of E.coli ATCC25922 decreased.This study provides a new method for the control of Escherichia coli.