Xu Tingting, Marr Enolia, Lam Haylie, Ripp Steven, Sayler Gary, Close Dan
Center for Environmental Biotechnology, University of Tennessee, 676 Dabney Hall, 1414 Circle Drive, Knoxville, TN, 37996, USA.
490 BioTech, Inc., 2450 E. J. Chapman Drive, Knoxville, TN, 37996, USA.
Ecotoxicology. 2015 Dec;24(10):2133-40. doi: 10.1007/s10646-015-1552-3. Epub 2015 Sep 30.
Escherichia coli O157:H7 is a significant human pathogen that is continually responsible for sickness, and even death, on a worldwide scale. While the pathology of E. coli O157:H7 infection has been well studied, the effect of it's multiple resulting cytotoxic mechanisms on host metabolic activity has not been well characterized. To develop a more thorough understanding of these effects, several bioluminescence assays were evaluated for their ability to track both toxicity and host metabolic activity levels in real-time. The use of continuously autobioluminescent human cells was determined to be the most favorable method for tracking these metrics, as its self-sufficient autobioluminescent phenotype was unaffected by the presence of the infecting bacteria and its signal could be measured without cellular destruction. Using this approach, it was determined that infection with as few as 10 CFU of E. coli O157:H7 could elicit cytotoxic effects. Regardless of the initial infective dose, an impact on metabolic expression was not observed until bacterial populations reached levels between 5 × 10(5) and 1 × 10(6) (R(2) = 0.933), indicating that a critical bacterial infection level must be reached prior to the onset of cytotoxic effects. Supporting this hypothesis, it was found that cells displaying infection-mediated metabolic activity reductions could recover to wild type metabolic activity levels if the infecting bacteria were removed prior to cell death. These results indicate that rapid treatment of E. coli O157:H7 infection could serve to limit host metabolic impact and reduce overall host cell death.
大肠杆菌O157:H7是一种重要的人类病原体，在全球范围内持续导致疾病甚至死亡。虽然对大肠杆菌O157:H7感染的病理学已经进行了充分研究，但其多种细胞毒性机制对宿主代谢活性的影响尚未得到很好的表征。为了更全面地了解这些影响，评估了几种生物发光测定法实时追踪毒性和宿主代谢活性水平的能力。使用持续自发光的人类细胞被确定为追踪这些指标的最有利方法，因为其自给自足的自发光表型不受感染细菌存在的影响，并且其信号可以在不破坏细胞的情况下进行测量。使用这种方法，确定感染低至10 CFU的大肠杆菌O157:H7即可引发细胞毒性作用。无论初始感染剂量如何，直到细菌数量达到5×10(5)至1×10(6)之间的水平时才观察到对代谢表达的影响（R(2)=0.933），这表明在细胞毒性作用开始之前必须达到临界细菌感染水平。支持这一假设的是，发现如果在细胞死亡之前去除感染细菌，显示出感染介导的代谢活性降低的细胞可以恢复到野生型代谢活性水平。这些结果表明，快速治疗大肠杆菌O(157):H7感染有助于限制宿主代谢影响并减少总体宿主细胞死亡。
