ABSTRACT: Comparative genomics to delineate pathogenic potential in non-O157 Shiga toxin-producing Escherichia coli (STEC) from patients with and without haemolytic uremic syndrome (HUS) in Norway.
Project description:We have used RNA sequencing to compare transcriptomes of 30 stx2a and eae positive STEC strains of non-O157 serogroups isolated from children < 5 years of age. The strains were from children with HUS (HUS group, n=15), and children with asymptomatic or mild disease (non-HUS group, n=15), either induced with mitomycin C or non-induced, to reveal potential differences in gene expression levels between groups. When the HUS and non-HUS group were compared for differential expression of protein-encoding gene families, 399 of 6119 gene families were differentially expressed (log2 fold change ≥ 1, FDR < 0.05) in the non-induced condition, whereas only one gene family was differentially expressed in the induced condition. Gene ontology and cluster analysis showed that several fimbrial operons, as well as a putative type VI secretion system (T6SS) were more highly expressed in the HUS group than in the non-HUS group, indicating a role of these in the virulence of STEC strains causing severe disease.
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.
Project description:Escherichia coli O157:H7 can cause haemorrhagic colitis and haemolytic uremic syndrome (HUS) in humans. This pathogen has been implicated in large food-borne outbreaks all over the world. By investigating the implicated salted salmon roe, Makino et al. (2000) suggested that E. coli O157:H7 in the viable but nonculturable (VBNC) state should be the culprit of the outbreak in Japan. High pressure CO2 (HPCD), one of the non-thermal pasteurization techniques, is an effective means to inactivate microorganisms. But in the previous study, we have demonstrated for the first time that HPCD could induce E. coli O157:H7 into the VBNC state, which poses a potential health risk to HPCD-treated products. In order to explore the potential formation mechanisms of VBNC E. coli O157:H7 induced by HPCD, the high-throughput Illumina RNA-seq transcriptomic analysis was conducted for E. coli O157:H7 cells treated at 5 MPa and 25 ℃ for 40 min (VBNC cells) and exponential-phase cells (the control). Finally, 97 genes that differentially transcribed between VBNC state and the control were obtained, with 22 genes up-regulated and 75 genes down-regulated in VBNC cells. These differentially expressed genes were classified in a variety of functional categories, including central metabolic processes, gene replication and expression, cell division, general stress response, respiration, membrane biosynthesis and transport and pathogenicity. Based on these differentially expressed genes, we suggest putative formation mechanisms of VBNC cells induced by HPCD. The finding will provide theoretical foundation for restraining the VBNC state formation under HPCD processing.
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 microarray data provided here belong to a study that describes two different Shiga toxin (Stx) induced models of hemolytic uremic syndrome (HUS) in mice. Although several rodent models of HUS were published, it still remains difficult to reproduce all clinical features of human HUS. Here, two different Stx2 regimes combined with volume resuscitation were tested in C57BL/6J wild type mice. Animals were euthanized because of kidney injury after 3 or 7 days respectively. Kidneys were removed for histological evaluation and RNA extraction. Kidney injury was confirmed histologically and by laboratory parameters in plasma. Data for the respective vehicle treated groups are also provided here.
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
Project description:Comparative Genomics of Shiga toxin-producing Escherichia coli (STEC) strains from pediatric patients with and without haemolytic uremic syndrome (HUS), 2000-2016, Finland
