Project description:While in transit within and between hosts, uropathogenic E. coli (UPEC) encounter multiple stresses, including substantial levels of nitric oxide and reactive nitrogen intermediates. Strains of UPEC become conditioned to high concentrations of acidified sodium nitrite (ASN), a model system used to generate nitrosative stress. We used microarrays to define the expression profile of UPEC that have been conditioned for growth in ASN.
Project description:Biocides are chemical compounds widely used in hospital settings for a variety of purposes, but mainly for disinfection. The chemical properties of a biocide, as well as the biocide concentration, influence which cellular targets are affected. Exposure of bacteria to residual concentrations of biocides could lead to development of increased resistance towards the biocide in use, as well as cross-resistance towards other antimicrobials, including antibiotics. The aim of this study was to examine whether biocides could induce any potentially relevant genes that could affect pathogen's drug resistance or fitness. By examining global gene expression of the uropathogenic Escherichia coli CFT073 after exposure to subinhibitory concentrations of four biocides (benzalkonium chloride - BAC, chlorhexidine - CHX, hydrogen peroxide - H2O2, triclosan - TSN), we found that each biocide changed expression of different groups of genes and that exposure to benzalkonum chloride caused changes in expression of the largest number of genes among all biocides. In general, the four biocides tested in this study at subinhibitory concentrations did not increase the resistance potential of the pathogen to other antimicrobials. We could, however, identify clusters of genes that could possibly help the strain to grow in the presence of a biocide in the medium.
Project description:E. coli which cause urinary tract infections must respond to high osmolarity in the urinary tract as well as the presence of urea. We used microarrays to measure the differntial gene expression of uropathogenic strain CFT073 in conditions of high osmolarity of urea v. minimal media
Project description:In the present study we have determined the global gene expression and biomolecular composition in an Escherichia coli model strain exposed to ten adverse conditions (sodium chloride, ethanol, glycerol, two acids (hydrochloric acid and acetic acid), sodium hydroxide, heat (46°C) and cold (15°C) as well as ethidium bromide and the disinfectant benzalkonium chloride). The large variation in responses and few common genes illustrates the adaptation potential of E. coli and its ability to survive and colonize a wide range of environments. Keywords: gene expression study, stress response
Project description:Transcriptional profiles of uropathogenic Escherichia coli CFT073 exposed to cranberry-derived proanthocyanidins (PACs) were determined. Our results indicate that bacteria grown on media supplemented with PACs were iron-deprived. To our knowledge, this is the first time that PACs have been shown to induce a state of iron-limitation in this bacterium.
Project description:Biocides are chemical compounds widely used in hospital settings for a variety of purposes, but mainly for disinfection. The chemical properties of a biocide, as well as the biocide concentration, influence which cellular targets are affected. Exposure of bacteria to residual concentrations of biocides could lead to development of increased resistance towards the biocide in use, as well as cross-resistance towards other antimicrobials, including antibiotics. The aim of this study was to examine whether biocides could induce any potentially relevant genes that could affect pathogen's drug resistance or fitness. By examining global gene expression of the uropathogenic Escherichia coli CFT073 after exposure to subinhibitory concentrations of five biocides (benzalkonium chloride - BAC, chlorhexidine - CHX, ethanol - EtOH, hydrogen peroxide - H2O2, triclosan - TSN), we found that each biocide changed expression of different groups of genes and that exposure to ethanol caused changes in expression of the largest number of genes among all biocides. In general, the five biocides tested in this study at subinhibitory concentrations did not increase the resistance potential of the pathogen to other antimicrobials. We could, however, identify clusters of genes that could possibly help the strain to grow in the presence of a biocide in the medium. A culture of E. coli CFT073 without any biocide treatment served as the control sample. That culture was grown under the exact same conditions as the five biocide-treated samples. Each sample was collected in three biological replicates at the mid-exponential phase of growth.
Project description:E. coli which cause urinary tract infections must respond to high osmolarity in the urinary tract as well as the presence of urea. We used microarrays to measure the differntial gene expression of uropathogenic strain CFT073 in conditions of high osmolarity of urea v. minimal media RNA was extracted from CFT073 in each growth condition and hybridized to an Affymetrix microarray. The differentially expressed genes were analyzed by expression pattern and function.
Project description:Urinary tract infections (UTIs) constitute a highly relevant model of microbial adaptation, in which the contrasting effects of pathogens and commensals on host tissues are clearly displayed. While virulent Escherichia coli cause severe, potentially life-threatening disease by breaking the inertia of the mucosal barrier and infecting the kidneys, the most common outcome of bacteriuria is an asymptomatic carrier state resembling commensalism at other mucosal sites. It remains unclear if the lack of destructive inflammation merely reflects low virulence or if carrier strains actively inhibit disease associated responses in the host. To address this question, we examined the effects of asymptomatic bacterial carriage on host gene expression. A498 cell line has been validated as a model of uropathogenic E. coli infection; the cells express functional receptors for bacterial virulence ligands and the response to virulent strains reflects human UTI. The cells were infected with asymptomatic and pathogenic E. coli in vitro, and harvested RNA was subjected to whole genome transcriptome analysis.