Project description:Enterohemorrhagic Escherichia coli (EHEC) is a gram negative enteric bacterial pathogen that can cause hemorrhagic colitis and heamolytic uremic syndrome (HUS) in humans and is the cause of bloody diarrhoea and acute renal failure in children. We have studied the transcriptional response of a colon cell line (CaCo2) to infection by EHEC and compared its profile to infection by EHEC shocked in acid at pH 2.5. We carried out microarray analysis on CaCo2 infected with EHEC O157H:7 EDL933 and EHEC shocked at pH 2.5 at 4 hours post infection.
Project description:Enterohemorrhagic Escherichia coli (EHEC) is a gram negative enteric bacterial pathogen that can cause hemorrhagic colitis and heamolytic uremic syndrome (HUS) in humans and is the cause of bloody diarrhoea and acute renal failure in children. We have studied the transcriptional response of a colon cell line (CaCo2) to infection by EHEC and compared its profile to infection by EHEC shocked in acid at pH 2.5. We carried out microarray analysis on CaCo2 infected with EHEC O157H:7 EDL933 and EHEC shocked at pH 2.5 at 4 hours post infection. CaCo2 cells were grown to 80% confluency and infected with acid shocked and unschocked bacteria for 4 hours before samples were collected for microarray analysis.
Project description:Enterohemorrhagic Escherichia coli (EHEC) is a gram negative enteric bacterial pathogen that can cause hemorrhagic colitis and heamolytic uremic syndrome (HUS) in humans and is the cause of bloody diarrhoea and acute renal failure in children. We have studied the transcriptional response of a colon cell line (CaCo2) to infection by EHEC and another closely related enteric pathogen Enteropathogenic Escherichia coli (EPEC) and compared its response to a cervical cell line (Hela). We carried out microarray analysis on CaCo2 infected with EHEC O157H:7 EDL933 and EPEC E2348/69 at 4 hours of infection and analysis on Hela infected with EHEC also at 4 hours of infection
Project description:Enterohemorrhagic Escherichia coli (EHEC) is a gram negative enteric bacterial pathogen that can cause hemorrhagic colitis and heamolytic uremic syndrome (HUS) in humans and is the cause of bloody diarrhoea and acute renal failure in children. We have studied the transcriptional response of a colon cell line (CaCo2) to infection by EHEC and another closely related enteric pathogen Enteropathogenic Escherichia coli (EPEC) and compared its response to a cervical cell line (Hela). We carried out microarray analysis on CaCo2 infected with EHEC O157H:7 EDL933 and EPEC E2348/69 at 4 hours of infection and analysis on Hela infected with EHEC also at 4 hours of infection CaCo2 cells and Hela cells were grown to 80% confluency and infected with the bacteria for 4 hours before samples were collected for microarray analysis.
Project description:The human intestinal microbiota associated with rats produces in vivo a soluble(s) factor(s) that down-regulates the expression of genes encoding for the Shiga toxin II in E. coli O157:H7. The Shiga toxin II is one of the major virulence factors of E. coli enterohemorragic leading to the deadly hemolitic and uremic syndrome. Investigation of the effect of the human intestinal microbiota on the whole transcriptome of EHEC O157:H7 is of major importance to increase our understanding of the pathogen transcriptomic adaptation in response to the human microbiota. We analysed by microarray hybridization the gene expression pattern of EHEC O157:H7 grown in the caecal content of germ-free rats or rats associated with the human microbiota of a healthy human subject. By doing so, we increased our understanding of the regulatory activities of the human gut microbiota on E. coli O157:H7
Project description:The human intestinal microbiota associated with rats produces in vivo a soluble(s) factor(s) that down-regulates the expression of genes encoding for the Shiga toxin II in E. coli O157:H7. The Shiga toxin II is one of the major virulence factors of E. coli enterohemorragic leading to the deadly hemolitic and uremic syndrome. Investigation of the effect of the human intestinal microbiota on the whole transcriptome of EHEC O157:H7 is of major importance to increase our understanding of the pathogen transcriptomic adaptation in response to the human microbiota. We analysed by microarray hybridization the gene expression pattern of EHEC O157:H7 grown in the caecal content of germ-free rats or rats associated with the human microbiota of a healthy human subject. By doing so, we increased our understanding of the regulatory activities of the human gut microbiota on E. coli O157:H7 A first group of twelve weeks old, male, germfree rats was colonized with the human fecal microbiota and a second group was kept germfree and condidered as a controle group. Rats were fed for two weeks with a sterile human type diet, and were sacrificed. E. coli O157:H7 was cultivated for 6 hours in the caecal content of germfree rats and rats associated with the human intestinal microbiota. RNAs were extracted and cDNAs were synthesized, fragmented and biotinylated before being hybridized on Affymetrix E. coli genome 2.0 arrays. The effect of the human intestinal microbiota was investigated by comparing the gene expression level in the caecal content of rats associated with the human microbiota with their expression level in the caecal content of the germfree rats.
Project description:Contamination with enterohemorrhagic Escherichia coli O157:H7 (EHEC) is a worldwide problem but there is no effective therapy available for EHEC infection. Biofilm formation is closely related with EHEC infection and is one of the mechanisms of antimicrobial resistance. Antibiofilm screening of 560 plant secondary metabolites against EHEC shows that ginkgolic acids C15:1 and C17:1 at 5 μg/ml and Ginko biloba extract at 100 μg/ml significantly inhibited EHEC biofilm formation on the surface of polystyrene, nylon membrane, and glass. Importantly, the working concentration of ginkgolic acids and G. biloba extract did not affect bacterial growth and has been known to be non-toxic to human. Transcriptional analyses showed that ginkgolic acid C15:1 repressed curli genes and prophage genes in EHEC, which were corroborated by reduced fimbriae production and biofilm reduction in EHEC. Interestingly, ginkgolic acids and G. biloba extract did not inhibit the biofilm formation of commensal E. coli K-12 strain. The current study suggests that plant secondary metabolites are important resource of biofilm inhibitors, as well as other bioactive compounds.
Project description:VS94 gene expression at different time-points in SAPI medium in absence and presence of AI-2 was studied. Autoinducer-2 (AI-2) is produced by many species of bacteria, including various commensal bacteria and is involved in inter-species communication. Since, pathogens encounter AI-2 once they enter the human gastro-intestinal tract; we studied the effects of presence of AI-2 on various phenotypes associated with infection and colonization of enterohemorrhagic Escherichia coli (EHEC) namely, chemotaxis, motility and attachment to HeLa cells. AI-2 attracted EHEC when observed in agarose plug assays and also increased EHEC motility by 1.44-fold. AI-2 also increased EHEC attachment to HeLa cells by 1.6-fold; hence, suggesting that exposure to AI-2 inside the gastro-intestinal tract can play an important role in EHEC colonization. We then investigated the global effects of AI-2 on EHEC gene expression using DNA microarrays at various time-points. We found that AI-2 controls virulence gene expression and several other groups of genes (flagellar genes, iron related genes, biofilm genes etc.) associated with virulence in a time-dependent manner. Hence, through these studies we have shown that AI-2 may be a key component in EHEC infection of human gastro-intestinal tract. Keywords: Time course
Project description:Enterohemorrhagic Escherichia coli (EHEC) is a food-borne pathogen that causes diarrheal disease and the potentially lethal hemolytic uremic syndrome. Here, we used an infant rabbit model of EHEC infection that recapitulates many aspects of human intestinal disease to comprehensively assess the host colonic epithelial and lamina propria cell transcriptional responses to EHEC infection. Furthermore, comparisons of colonic pathology and intestinal transcriptomic profiles in animals infected with EHEC strains containing or lacking Shiga toxins (∆∆stx) were carried out to investigate how these potent toxins shape the host response to the pathogen. We found that Stx is required for severe, multi-focal hemorrhage and extensive apoptosis in the colon. RNA-sequencing revealed that EHEC infection elicits a robust innate immune response in the colonic epithelium that is dramatically shaped by Stx. Over 1400 genes were differentially expressed in animals infected with WT versus ∆∆stx EHEC strains. Several pathways linked to innate immune responses were dependent on Stx. Upregulated genes in the presence of toxin included cytokines IL23a and CXCL8, as well as F3, the gene encoding the coagulation initiator Tissue Factor. RNA FISH revealed that these elevated transcripts were found almost exclusively in epithelial cells, suggesting that Stx remodels the transcriptional profile of the epithelium. Collectively, these findings reveal that Stx potently modulates the innate immune response to EHEC in the intestine, and suggest that Stx drives the response to infection towards type 3 immunity.
Project description:Shiga toxin type 2 (Stx2) from Escherichia coli is thought to be a main factor to casue renal dysfunction in Enterohemorrhagic E. coli (EHEC) infection. The renal dysfunction caused by the proximal tubular defects can be detected in the earlier EHEC infection. However, the precise information of gene expression from proximal tubular epithelial cells has yet to be clarified. We performed microarray experiments using Stx2-injected mouse kidney and Stx2-treated human renal proximal tubular epithelial cells (RPTEC), and extracted common genes that were differentially expressed.