Department of Food Microbiology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany.
Int J Food Microbiol. 2010 Nov 15;144(1):133-40. doi: 10.1016/j.ijfoodmicro.2010.09.010. Epub 2010 Sep 17.
In this study, we investigated the interaction of 19 benign strains of lactic acid bacteria (LAB), bifidobacteria and staphylococci with enterohemorrhagic Escherichia coli (EHEC) strains of different serotypes and virulence gene spectrum in a HT29 cell culture infection model. As markers of infection, the secretion of interleukin 8 (IL-8) and the activation of the transcription factor NF-κB by the infected cells were determined. With 12 of 19 tested strains, a weak reduction <30% of IL-8 secretion of HT29 cells after co-infection with EHEC O157:H7 strain EDL933 was observed. Six strains reduced the IL-8 secretion up to 60% and the strain B. adolescentis DSMZ 20086 decreased the IL-8 production about 73%. In further co-infection assays with EHEC strains of the serotypes O103:H2, O26:H⁻, 0157:H⁻ and O113:H21, different abilities of the LAB strains to influence the infection with the different EHEC strains were noted. Therefore, the protective anti-inflammatory effect is strain specific for LAB and also depends on the application of EHEC strains with different sero- and virulence types. The differences in efficacy of protective bacteria against certain EHEC strains were unexpected and have not been shown so far. Furthermore, we could show that the inhibitory effects were not attributed to lower adhesion abilities of EHEC to the production of organic acids by the benign bacteria. In addition, viable bacteria are needed to inhibit the IL-8 secretion. Moreover, the NF-κB activation was reduced significantly by all tested LAB strains in co-infection trials, but was not strain-specific. The model described here is useful to screen for basic effects of protective bacteria that are able to counteract EHEC-mediated effects on human cells, and to study the molecular interaction between bacteria as well as between bacteria and human cultured cells.
在这项研究中，我们在 HT29 细胞培养感染模型中研究了 19 株良性乳酸菌（LAB）、双歧杆菌和葡萄球菌与不同血清型和毒力基因谱的产肠出血性大肠杆菌（EHEC）菌株的相互作用。作为感染标志物，测定了受感染细胞中白细胞介素 8（IL-8）的分泌和转录因子 NF-κB 的激活。用 19 株测试菌株中的 12 株，在与 EHEC O157:H7 株 EDL933 共同感染后，观察到 HT29 细胞的 IL-8 分泌减少<30%。6 株菌株将 IL-8 分泌减少到 60%，而菌株 B. adolescentis DSMZ 20086 将 IL-8 产量降低了约 73%。在与 O103:H2、O26:H⁻、0157:H⁻和 O113:H21 血清型的 EHEC 菌株的进一步共同感染试验中，注意到 LAB 菌株影响不同 EHEC 菌株感染的能力不同。因此，LAB 的这种保护性抗炎作用是菌株特异性的，并且还取决于应用具有不同血清型和毒力类型的 EHEC 菌株。针对某些 EHEC 菌株的保护性细菌的功效差异是出乎意料的，迄今为止尚未显示。此外，我们还表明，抑制作用不是由于良性细菌产生的有机酸降低了 EHEC 对细菌的粘附能力。此外，需要活细菌来抑制 IL-8 的分泌。此外，在共同感染试验中，所有测试的 LAB 菌株均显著降低了 NF-κB 的激活，但不是菌株特异性的。这里描述的模型可用于筛选能够对抗 EHEC 介导的对人细胞的影响的保护性细菌的基本作用，并研究细菌之间以及细菌与人培养细胞之间的分子相互作用。
