title: Real-time toxicity and metabolic activity tracking of human cells exposed to Escherichia coli O157:H7 in a mixed consortia.
abstract: 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.
authors.affiliation: Center for Environmental Biotechnology, University of Tennessee, 676 Dabney Hall, 1414 Circle Drive, Knoxville, TN, 37996, USA.
authors.forename: Tingting
authors.initials: T
authors.lastname: Xu
authors.affiliation: Center for Environmental Biotechnology, University of Tennessee, 676 Dabney Hall, 1414 Circle Drive, Knoxville, TN, 37996, USA.
authors.forename: Enolia
authors.initials: E
authors.lastname: Marr
authors.affiliation: Center for Environmental Biotechnology, University of Tennessee, 676 Dabney Hall, 1414 Circle Drive, Knoxville, TN, 37996, USA.
authors.forename: Haylie
authors.initials: H
authors.lastname: Lam
authors.affiliation: 490 BioTech, Inc., 2450 E. J. Chapman Drive, Knoxville, TN, 37996, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Ripp
authors.affiliation: Center for Environmental Biotechnology, University of Tennessee, 676 Dabney Hall, 1414 Circle Drive, Knoxville, TN, 37996, USA.
authors.forename: Gary
authors.initials: G
authors.lastname: Sayler
authors.affiliation: 490 BioTech, Inc., 2450 E. J. Chapman Drive, Knoxville, TN, 37996, USA. dan.close@490BioTech.com.
authors.forename: Dan
authors.initials: D
authors.lastname: Close
mesh_terms: D015169:Colony Count, Microbial; D019453:Escherichia coli O157 / Q000502:physiology*; D057809:HEK293 Cells; D006801:Humans; D059013:Microbial Consortia
keywords: Bioluminescence; Cell culture; E. coli O157:H7; Optical imaging; Toxicology