Food poisoning caused by bacteria is one of the most important concerns in food hygiene. The use of probiotics in prevention, control, and treatment of these infections has been considerably increased in recent years. This study evaluated the effect of B. coagulans cell free supernatant (CFS) on growth of Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, non-pathogenic Escherichia coli, and Escherichia coli 0157:H7 by the broth dilution method. The cytotoxicity, and apoptosis induced by pathogens alone and in co-culture with B. coagulans or its CFS were measured by trypan blue, and fluorescence staining methods. The expression level of interleukin-8 (IL-8) cytokine-encoding genes was also investigated by a qRT-PCR assay in all pathogens and co-cultured groups in HT-29 cells. Our results showed that 4% B. coagulans CFS reduced pathogen growth. The highest rate of growth inhibition was observed in L. monocytogenes. We also found that B. coagulans, and its 4% CFS reduced the cytotoxic effects of pathogens, with the exception of S. aureus. Non-pathogenic E. coli also had no significant cytotoxic effect on the cells. Examination of the treated cells with acridine orange/ethidium bromide staining showed reductions in the rate of cell damage (including early apoptosis, late apoptosis, and necrosis) in pathogen-probiotic co-cultures. Furthermore, we showed that co-culture of pathogens with B. coagulans significantly down-regulated IL-8 gene expression (P < 0.05). The greatest down-regulation compared with pathogen alone was observed in S. aureus. Hence, B. coagulans can be considered as an appropriate probiotic to diminish cytotoxicity, and inflammatory response of enteropathogenic bacteria.

由细菌引起的食物中毒是食品卫生中最重要的问题之一。近年来，益生菌在这些感染的预防、控制和治疗中的使用显着增加。本研究通过肉汤稀释法评估了凝结芽孢杆菌无细胞上清液 (CFS) 对蜡样芽孢杆菌、单核细胞增生李斯特菌、金黄色葡萄球菌、非致病性大肠杆菌和大肠杆菌0157:H7 生长的影响。病原体单独和与凝结芽孢杆菌共培养时诱导的细胞毒性和细胞凋亡或其CFS采用台盼蓝、荧光染色法测定。还通过 qRT-PCR 测定在 HT-29 细胞中的所有病原体和共培养组中研究了白介素 8 (IL-8) 细胞因子编码基因的表达水平。我们的结果表明，4% B. coagulans CFS 减少了病原体的生长。在单核细胞增生李斯特菌中观察到最高的生长抑制率。我们还发现B. coagulans及其 4% CFS 降低了病原体的细胞毒性作用，金黄色葡萄球菌除外。非致病性大肠杆菌对细胞也没有明显的细胞毒作用。用吖啶橙/溴化乙锭染色检查处理过的细胞显示病原体-益生菌共培养物中细胞损伤率（包括早期凋亡、晚期凋亡和坏死）降低。此外，我们发现病原体与凝结芽孢杆菌共培养显着下调IL-8基因表达（P  < 0.05）。在金黄色葡萄球菌中观察到与单独病原体相比最大的下调。因此，B. coagulans可以被认为是一种合适的益生菌，以减少肠道病原菌的细胞毒性和炎症反应。