Background Majority of enteric infections are foodborne and antimicrobials including antibiotics have been used for their control and treatment. However, probiotics or prebiotics or their combination offer a potential alternative intervention strategy for improving the host health and preventing foodborne pathogen colonization/infections in reservoir. Further, bioengineered probiotics expressing bioactive products to achieve specific function is highly desirable. Recently, we over-expressed mcra (myosin cross-reactive antigen) gene in Lactobacillus casei (Lc) and developed a bioengineered probiotics Lc + CLA which produce higher amounts of metabolites including conjugated linoleic acid (CLA). Furthermore, we also reported that prebiotic like components such as berry pomace (byproduct) phenolic extracts (BPEs) can enhance the growth of probiotics and improved the beneficial effects of probiotics. In this study, we evaluated the antimicrobial effect of modified Lc + CLA in combination of BPEs on growth, survival and pathogenesis of enterohemorrhagic Escherichia coli (EHEC). Results In mixed culture condition, the growth of EHEC was significantly reduced in the presence Lc + CLA and/or BPEs. Cell-free cultural supernatant (CFCS) collected from Lc or Lc + CLA strain also inhibited the growth and survival of EHEC and the inhibitory effects of CFCSs against EHEC were enhanced in the presence of BPEs in concentration dependent manner. Interaction between EHEC and intestinal epithelial INT-407 cells were also altered significantly in the presence of either Lc or Lc + CLA strain or their CFCSs with or without BPEs. The expression of multiple virulence genes and physicochemical properties of EHEC were also altered when the bacterial cells were pretreated with CFCSs and/or BPEs. Conclusions These results showed that diet containing bioactive Lc + CLA and natural prebiotic like component such as BPEs might be an effective way to prevent foodborne infections with EHEC.

中文翻译：

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亚油酸过量产生干酪乳杆菌与浆果酚提取物对肠出血性大肠杆菌发病机制的合生作用。

背景 大多数肠道感染是食源性感染，包括抗生素在内的抗微生物药物已被用于控制和治疗。然而，益生菌或益生元或它们的组合提供了一种潜在的替代干预策略，用于改善宿主健康和预防食源性病原体在宿主中的定植/感染。此外，表达生物活性产物以实现特定功能的生物工程益生菌是非常需要的。最近，我们在干酪乳杆菌 (Lc) 中过表达 mcra（肌球蛋白交叉反应抗原）基因，并开发了一种生物工程益生菌 Lc + CLA，可产生更高量的代谢物，包括共轭亚油酸 (CLA)。此外，我们还报道了类似益生元的成分，例如浆果渣（副产品）酚类提取物 (BPE)，可以促进益生菌的生长并提高益生菌的有益效果。在本研究中，我们评估了修饰的 Lc + CLA 与 BPE 组合对肠出血性大肠杆菌 (EHEC) 生长、存活和发病机制的抗菌作用。结果在混合培养条件下，EHEC的生长在Lc + CLA和/或BPEs存在下显着降低。从 Lc 或 Lc + CLA 菌株收集的无细胞培养上清 (CFCS) 也抑制 EHEC 的生长和存活，并且在 BPE 存在下以浓度依赖性方式增强 CFCS 对 EHEC 的抑制作用。EHEC 和肠上皮 INT-407 细胞之间的相互作用在存在或不存在 BPE 的 Lc 或 Lc + CLA 菌株或其 CFCS 存在下也发生了显着变化。当细菌细胞用 CFCS 和/或 BPE 预处理时，EHEC 的多种毒力基因的表达和理化性质也发生了改变。结论 这些结果表明，含有生物活性 Lc + CLA 和天然益生元类成分（如 BPE）的饮食可能是预防 EHEC 食源性感染的有效方法。