engleski

Quaternary ammonium salt based disinfectants reduce the expression of listeriolysin O in Listeria monocytogenes

Bacterial resistance, caused among others by frequent use of disinfectants and antibiotics, has become one of the major problems in food industry. Therefore, better understanding of mechanisms of action of disinfectants is of great importance. Quaternary ammonium salts (QAC) have been extensively used as antimicrobial agents in food- processing industries and medicine. In this study, proteomic methods were used to identify changes in the proteome of foodborne pathogen Listeria monocytogenes after treatment with three QAC based disinfectants. LC-MS/MS analysis, followed by gene ontology searching, reveals disturbance in the synthesis of plasma membrane proteins and cell wall proteoglycans in treated samples. Down- regulation of some of key proteins from this group, that are important for bacterial growth, is also observed. Additionally, it is shown that Listeriolysin O (LLO), the major virulence factor of L. monocytogenes, is significantly down- regulated after treatment with each of the three investigated inhibitors. These results contribute to the already hypothesized mechanism of action of QAC-based inhibitors in Gram-positive bacteria that results in the disturbance of key cell surface proteins and proteoglycans. Furthermore, significant inhibition of Listeriolysin O suggests that this protein can be used as potential biomarker candidate for food contamination with L. monocytogenes.

foodborne pathogens, listeriolysin o, mechanism of action, proteome changes

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