Transcriptional changes involved in inhibition of biofilm formation by ε-Polylysine in Salmonella Typhimurium

Salmonella Typhimurium is one of the major foodborne pathogens due to its biofilm formation on food contact surfaces. A polymer of positively charged lysine, ε-Polylysine has been demonstrated to inhibit biofilm formation of both Gram-positive and -negative bacteria. To elucidate the mechanism for inhibition of biofilm formation by ε-Polylysine, transcriptional profiles were compared between the cells before and after treatment with ε-Polylysine in Salmonella Typhimurium. A genome-wide DNA microarray analysis was performed after cultivation in 0.1% bacto soytone in the presence of 0.001% ε-Polylysine at 30°C for 2 h. Genes involved in curli and cellulose production, quorum sensing, and flagellar motility were down-regulated, whereas genes associated with colanic acid synthesis were up-regulated. The data from microarray was validated by RT-qPCR. Furthermore, production of colanic acid in S. Typhimurium decreased in the presence of ε-Polylysine. The outcome of this study provides a basic understanding of the anti-biofilm mechanisms of ε-Polylysine and may contributes to develop new disinfectant to control biofilm during food manufacturing and storage. Gene expression during initial adhension (2 hours) were measured with or withour exposure to 0.001% ε-Polylysine. Three dependent experiments were performed at each time.