Proteomic changes in EHEC O157:H7 under catechin intervention.

ABSTRACT

Catechin exhibits antimicrobial activity against various microorganisms, such as EHEC O157H7. This study reports the bactericidal effect of catechin on EHEC O157H7 in simulated human gastrointestinal environment and the underlying antibacterial mechanism. Bacteriostasis test results showed that the minimum bactericidal concentration of catechin for EHEC O157H7 was 5 g/L. The bactericidal effect of catechin in the gastrointestinal juice became more significant with increased culture time, and catechin exhibited a synergistic effect with bile salt in inhibiting EHEC O157H7. Changes in the profile of protein expression in EHEC O157H7 in response to catechin intervention were investigated. Two-dimensional electrophoresis identified 34 proteins with significantly altered expression. A total of 2 and 12 proteins were upregulated and downregulated, respectively. However, 20 proteins disappeared. No new protein was expressed compared with the control. Hence, catechin intervention resulted in diverse changes in the expression of proteins associated with cell structure and genetic information processing. Catechin could cause the disappearance of certain proteins or the destruction of certain peptides. These processes lead to the inhibition of EHEC O157 H7 cells.