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Identification of differentially expressed genes between clinical and bovine-biased Escherichia coli O157:H7 genotypes

ABSTRACT: Escherichia coli O157:H7 strains have been classified into different genotypes based on the presence of specific shiga toxin-encoding bacteriophage insertion sites. Genotypes that are predominant in clinical isolates are named clinical genotypes and those that are isolated mostly from bovine sources are bovine-biased genotypes. To determine whether inherent differences in gene expression could possibly explain the variation in infectivity of these genotypes, we compared the expression patterns of O157:H7 strains isolated from cattle, which belonged to either clinical genotype 1 or bovine-biased genotype 5. Important virulence factors of O157, including locus of enterocyte effacement, enterohemolysin, and pO157 plasmid encoded genes, showed increased expression in clinical genotype. Genes essential for acid resistance such as gadA, gadB, and gadC and other stress fitness-associated genes were up-regulated in the bovine-biased genotype 5. Overall, these results suggest that clinical genotype 1 strains more commonly cause human illness because of an enhanced ability to express O157 virulence factors known to be important for disease pathogenesis. By contrast, strains of the bovine-biased genotype 5 appear to be more resistant to adverse environmental conditions, which enable them to survive well in bovines without causing disease.

ORGANISM(S): Escherichia coli

PROVIDER: GSE15783 | GEO | 2009/04/24

SECONDARY ACCESSION(S): PRJNA116857

REPOSITORIES: GEO

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Identification of differentially expressed genes between clinical and bovine-biased Escherichia coli O157:H7 genotypes

Project description:Escherichia coli O157:H7 strains have been classified into different genotypes based on the presence of specific shiga toxin-encoding bacteriophage insertion sites. Genotypes that are predominant in clinical isolates are named clinical genotypes and those that are isolated mostly from bovine sources are bovine-biased genotypes. To determine whether inherent differences in gene expression could possibly explain the variation in infectivity of these genotypes, we compared the expression patterns of O157:H7 strains isolated from cattle, which belonged to either clinical genotype 1 or bovine-biased genotype 5. Important virulence factors of O157, including locus of enterocyte effacement, enterohemolysin, and pO157 plasmid encoded genes, showed increased expression in clinical genotype. Genes essential for acid resistance such as gadA, gadB, and gadC and other stress fitness-associated genes were up-regulated in the bovine-biased genotype 5. Overall, these results suggest that clinical genotype 1 strains more commonly cause human illness because of an enhanced ability to express O157 virulence factors known to be important for disease pathogenesis. By contrast, strains of the bovine-biased genotype 5 appear to be more resistant to adverse environmental conditions, which enable them to survive well in bovines without causing disease. The results are based on O157:H7 clinical and bovine-biased genotype cultures grown in DMEM medium to exponential phase. Four strains were selected from each genotype and strains were considered as biological replicates. A double loop microarray design was used for comparing the samples. Differences in transcript levels were determined using a mixed model ANOVA in R/MAANOVA which tested for significant differences due to strain (clinical or bovine-biased) using the following linear model: array+dye+sample (biological replicate)+strain+error. We incorporated the dye-swaps among the biological replicates.

2010-06-19 | E-GEOD-15783 | biostudies-arrayexpress

Identification of genes regulated by gadE in E. coli O157:H7

Project description:Integrating laterally acquired virulence genes into the backbone regulatory network is important for the pathogenesis of Escherichia coli O157:H7, which has captured many virulence genes through horizontal transfer during evolution. GadE is an essential transcriptional activator of glutamate decarboxylase (GAD) system, the most efficient acid resistance mechanism in E. coli. The full contribution of GadE to the acid resistance and virulence of pathogenic E. coli O157:H7 remains largely unknown. We inactivated gadE in E. coli O157:H7 Sakai and compared global transcription profiles with that of wild type in exponential and stationary phases of growth using microarrays containing 6088 ORFs from three E. coli genomes. gadE inactivation significantly altered the expression of 60 genes independent of growth phase and 122 genes in a growth phase-dependent manner. Inactivation of gadE markedly down-regulated the expression of gadA, gadB, gadC and many acid fitness island genes in a growth phase-dependent manner. Nineteen genes encoded on the locus of enterocyte effacement (LEE), including ler, showed a significant increase in expression upon gadE inactivation. Altogether, our data indicate that GadE is critical for acid resistance of E. coli O157:H7 and plays an important role in virulence by down-regulating expression of LEE.

2008-10-11 | GSE13132 | GEO

Comparative Transcriptomics Analysis of Shiga Toxin Producing Escherichia coli O157:H7 Grown in Bovine Rectoanal Junction Cells and Human Colonic Epithelial Cells

Project description:Shiga toxin-producing Escherichia coli (STEC) O157:H7 is a notorious foodborne pathogen capable of causing severe gastrointestinal infections in humans. The bovine rectoanal junction (RAJ) has been identified as a primary reservoir of STEC O157:H7, playing a critical role in its transmission to humans through contaminated food sources. Despite the relevance of this host-pathogen interaction, the molecular mechanisms behind the adaptation of STEC O157:H7 in the bovine RAJ and its subsequent infection of human colonic epithelial cells remain largely unexplored. This study aimed to unravel the intricate dynamics of STEC O157:H7 in two distinct host environments: bovine RAJ squamous epithelial (RSE) cells and human colonic epithelial cells. Comparative transcriptomics analysis was employed to investigate the differential gene expression profiles of STEC O157:H7 during its interaction with these cell types. The bacterial cells were cultured under controlled conditions to simulate the microenvironments of both bovine RAJ and human colonic epithelial cells. Using high-throughput RNA sequencing, we identified key bacterial genes and regulatory pathways that are significantly modulated in response to each specific host environment. Our findings reveal distinct expression patterns of virulence factors, adhesion proteins, and stress response genes in STEC O157:H7 grown in bovine RAJ cells as opposed to human colonic epithelial cells. Additionally, the comparative analysis highlights the potential role of certain genes in host adaptation and tissue-specific pathogenicity. Furthermore, this study sheds light on the potential factors contributing to the survival and persistence of STEC O157:H7 in the bovine reservoir and its ability to colonize and cause disease in humans.

2023-11-09 | GSE240423 | GEO

Identification of genes regulated by gadE in E. coli O157:H7

2010-05-18 | E-GEOD-13132 | biostudies-arrayexpress

Escherichia coli

Project description:Identification of differentially expressed genes between clinical and bovine-biased Escherichia coli O157:H7 genotypes

| PRJNA116857 | ENA

Transcriptional profiling of 2 outbreak strains of E. coli O157:H7 following exposure to epithelial cells

2009-09-17 | GSE17389 | GEO

Secretome analysis of diarrhea inducing strains of Escherichia coli

Project description:Secreted proteins constitute a major part of virulence factors that are responsible for pathogenesis caused by gram negative bacteria. Enterohemorrhagic Escherichia coli (E. coli), EHEC O157:H7 is the major pathogen often causing outbreaks. There is growing evidence that non-O157:H7 E. coli strains may also be involved in the recent outbreaks. However, there is no systematic study describing differential secreted proteins from non-O157:H7 E. coli strains. Here, we have applied isobaric tag-based TMT labeling combined with high-resolution Fourier transform mass spectrometry to study the differential secretome analysis of major non-O157:H7 E. coli strains, O103, O111, O121, O145, O26 and O45, which is known as diarrhea inducing non-O175:H7 ATCC “big six” serogroup E. coli strains. We identified 1,240 proteins quantitatively identified, 565 proteins were found to be secreted as predicted by PSORTb and SecretomeP. We identified 310 proteins containing signal peptide and 255 proteins as secreted. We identified 20 strain specific proteins with in big-six group and was confirmed by proteogenomics approach. Further we enriched and have shown relative expression of type III secretion system. To our knowledge, this study is the first comparative proteomic study on secretome of E. coli big six serogroup and the several of these strain specific secreted proteins can be further studied to develop potential markers for identification and strain level differentiation. Moreover, the results of this study can be utilized in several applications, including food safety, diagnostics of E. coli outbreaks, and biodefense.

2018-07-05 | PXD004372 | Pride

Transcriptomes of genetically distinct E. coli O157:H7 strains

Project description:Transcriptomes of 24 clinical strains of E. coli O157:H7 that differ phylogenetically and by Shiga toxin profiles were compared after 30 min co-incubation with epithelial cells.

2010-07-22 | GSE20397 | GEO

IgG binds Escherichia coli serine protease EspP and protects mice from E. coli O157:H7 infection

Project description:The effect of pooled immunoglobulins (IgG) on E. coli O157:H7 colonization and the course of disease in an EHEC mouse model was investigated showing an improved survival and decreased intestinal and renal pathology. Treatment was given after inoculation thereby corresponding to the clinical setting. In vitro studies identified E. coli serine protease EspP as the E. coli O157:H7 protein that IgG bound to, via the Fc fragment, in both murine and human IgG preparations, and blocked its enzymatic activity. EspP is a virulence factor previously shown to promote colonic cell injury and the uptake of Shiga toxin by intestinal cells. The results suggest that IgG in commercial preparations binds to EspP protecting the host from E. coli O157:H7 infection and could potentially be beneficial in patients.

2022-02-08 | PXD029563 | Pride

Transcriptional profiling of 2 outbreak strains of E. coli O157:H7 following exposure to epithelial cells

Project description:Two outbreak strains of E. coli O157:H7 differ phylogenetically, in gene content, and in epidemiological characteristics. The working hypothesis in this experiment was that these strains will also differ in the transcription of shared virulence genes. Indeed, following a 30 minute exposure to epithelial cells, strain TW14359 overexpressed major and ancillary virulence genes, relative to strain Sakai. E. coli O157:H7 strains were physiologically normalized by growth to stationary phase, twice, in MOPS minimal media. Cultures were then transferred to DMEM media for adaptation. After 3 h of growth in DMEM, O157:H7 cultures were used to infect monolayers of MAC-T epithelial cells. 30 min following incubation, aliquots of suspended, non-adherent bacteria were used for RNA extraction. Five biological replications of the experiment were performed with each strain and, together with dye-swaps, 10 array hybridizations were carried out. Array data were fitted to a mixed model ANOVA using the following linear model: array+dye+sample (biological replicate)+strain+error.

2010-05-05 | E-GEOD-17389 | biostudies-arrayexpress

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