In vitro antibacterial activity of Bacillus coagulans T242 on Caco-2 cells infected with Salmonella Typhimurium

This study aimed to investigate the antibacterial activity of Bacillus coagulans (B. coagulans) T242 and its ability to alleviate the infection of Caco-2 cells with Salmonella Typhimurium (S. Typhimurium) SL1344. B. coagulans T242 has a broad spectrum of the antibacterial activity. The cell-free supernatants of B. coagulans T242 inhibited the growth of S. Typhimurium SL1344 and changed its cell morphology. B. coagulans T242 inhibited the adhesion and invasion of S. Typhimurium SL1344 to Caco-2 cells by adhering to Caco-2 cells, significantly reduced the production of interleukin-6 (IL-6), Interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) which induced by S. Typhimurium SL1344, also increased interleukin-10 (IL-10) production, thereby alleviating the inflammatory response of Caco-2 cells. B. coagulans T242 vegetative cells and spores could alleviate the decreased expression of tight junction proteins (Claudin-1, Occludin and ZO-1) caused by S. Typhimurium SL1344 infection in Caco-2 cells by increasing the expression of Claudin-1, Occludin and ZO-1. This study demonstrated that B. coagulans T242 could protect Caco-2 cells by adhesion, reducing inflammatory response and enhancing intestinal barrier function. Therefore, B. coagulans T242 will hopefully be an effective alternative to antibiotics, and this study has important implications for food safety issues.