Draft Genome Sequence of Citrobacter rodentium DBS100 (ATCC 51459), a Primary Model of Enterohemorrhagic Escherichia coli Virulence

Lenz, Abigail; Tomkins, Jeffrey; Fabich, Andrew J.

doi:10.1128/genomea.00415-15

Cited by 6 publications

(4 citation statements)

References 5 publications

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“…The microarray slides were custom-made using photolithography by MYcroarray, with 3 probes of 45 nucleotides each, per gene, against the C. rodentium DBS100 genome (Lenz et al, 2015 ). The labeled cDNA and gDNA were hybridized onto the microarray slide as described previously (Faucher and Shuman, 2013 ).…”

Section: Methodsmentioning

confidence: 99%

The Virulence Effect of CpxRA in Citrobacter rodentium Is Independent of the Auxiliary Proteins NlpE and CpxP

Giannakopoulou

Mendis

Zhu

et al. 2018

Front. Cell. Infect. Microbiol.

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Citrobacter rodentium is a murine pathogen used to model the intestinal infection caused by Enteropathogenic and Enterohemorrhagic Escherichia coli (EPEC and EHEC), two diarrheal pathogens responsible for morbidity and mortality in developing and developed countries, respectively. During infection, these bacteria must sense and adapt to the gut environment of the host. In order to adapt to changing environmental cues and modulate expression of specific genes, bacteria can use two-component signal transduction systems (TCS). We have shown that the deletion of the Cpx TCS in C. rodentium leads to a marked attenuation in virulence in C3H/HeJ mice. In E. coli, the Cpx TCS is reportedly activated in response to signals from the outer-membrane lipoprotein NlpE. We therefore investigated the role of NlpE in C. rodentium virulence. We also assessed the role of the reported negative regulator of CpxRA, CpxP. We found that as opposed to the ΔcpxRA strain, neither the ΔnlpE, ΔcpxP nor the ΔnlpEΔcpxP strains were significantly attenuated, and had similar in vivo localization to wild-type C. rodentium. The in vitro adherence of the Cpx auxiliary protein mutants, ΔnlpE, ΔcpxP, ΔnlpEΔcpxP, was comparable to wild-type C. rodentium, whereas the ΔcpxRA strain showed significantly decreased adherence. To further elucidate the mechanisms behind the contrasting virulence phenotypes, we performed microarrays in order to define the regulon of the Cpx TCS. We detected 393 genes differentially regulated in the ΔcpxRA strain. The gene expression profile of the ΔnlpE strain is strikingly different than the profile of ΔcpxRA with regards to the genes activated by CpxRA. Further, there is no clear inverse correlation in the expression pattern of the ΔcpxP strain in comparison to ΔcpxRA. Taken together, these data suggest that in these conditions, CpxRA activates gene expression in a largely NlpE- and CpxP-independent manner. Compared to wildtype, 161 genes were downregulated in the ΔcpxRA strain, while being upregulated or unchanged in the Cpx auxiliary protein deletion strains. This group of genes, which we hypothesize may contribute to the loss of virulence of ΔcpxRA, includes T6SS components, ompF, the regulator for colanic acid synthesis, and several genes involved in maltose metabolism.

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Section: Methodsmentioning

confidence: 99%

The Virulence Effect of CpxRA in Citrobacter rodentium Is Independent of the Auxiliary Proteins NlpE and CpxP

Giannakopoulou

Mendis

Zhu

et al. 2018

Front. Cell. Infect. Microbiol.

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“…To this end, we chose the mouse pathogen Citrobacter rodentium ϕ stx 2dact (DBS770), which produces Stx 2dact and recapitulates the disease pathology of human EHEC infection in mice [ 36 ]. DBS770 is a derivative of C. rodentium DBS100 [ 37 ]. Due to the presence of stx 2dact , it is considered a BSL-3** level pathogen, and experiments with the strain have to be performed under high containment settings, which impedes experimentation.…”

Section: Resultsmentioning

confidence: 99%

Scalable Reporter Assays to Analyze the Regulation of stx2 Expression in Shiga Toxin-Producing Enteropathogens

Koeppel

Glaser

Baumgärtner

et al. 2021

Toxins

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Stx2 is the major virulence factor of EHEC and is associated with an increased risk for HUS in infected patients. The conditions influencing its expression in the intestinal tract are largely unknown. For optimal management and treatment of infected patients, the identification of environmental conditions modulating Stx2 levels in the human gut is of central importance. In this study, we established a set of chromosomal stx2 reporter assays. One system is based on superfolder GFP (sfGFP) using a T7 polymerase/T7 promoter-based amplification loop. This reporter can be used to analyze stx2 expression at the single-cell level using FACSs and fluorescence microscopy. The other system is based on the cytosolic release of the Gaussia princeps luciferase (gluc). This latter reporter proves to be a highly sensitive and scalable reporter assay that can be used to quantify reporter protein in the culture supernatant. We envision that this new set of reporter tools will be highly useful to comprehensively analyze the influence of environmental and host factors, including drugs, small metabolites and the microbiota, on Stx2 release and thereby serve the identification of risk factors and new therapies in Stx-mediated pathologies.

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“…When studying human GI disease such as inflammatory bowel disease and colitis, mice have become the preferred small animal model as they have similar GI tracts to their human counterparts. However, since EHEC is a human-specific pathogen, it does not readily colonize the mouse GI tract (Lenz et al, 2015;Wiles et al, 2006a). This can be manipulated by infecting mice with extremely high doses of EHEC, or by using germ-free or streptomycin-treated mice, however these models do not give an accurate biological representation of infection (Rodrigues et al, 2012;Smith and Bhagwat, 2013).…”

Section: Comparison To Ehecmentioning

confidence: 99%

“…Citrobacter rodentium (C. rodentium) (Lenz et al, 2015;Rodrigues et al, 2012;Wiles et al, 2006a). The two most commonly used strains are ICC168 and DBS100, both of which were isolated from a diarrhea outbreak in mice at Yale University School of Medicine in 1972 (Lenz et al, 2015).…”

Section: Comparison To Ehecmentioning

confidence: 99%

Understanding and exploiting the response of EHEC O157:H7 to human gastrointestinal chemical signals

Lackraj¹

2021

Preprint

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Enterohemorrhagic Escherichia coli (EHEC) is a clinically relevant foodborne pathogen, resulting in over 95,000 cases of EHEC-associated illness and 60 deaths each year in the US alone. Since EHEC is a continuous global issue with new outbreaks constantly occurring, the development of new therapeutic strategies is vital to minimizing the cases of infection seen each year. A key aspect in new drug development is the identification of vulnerabilities in EHEC’s pathogenicity, in particular, during its transit through the human gastrointestinal (GI) tract. As EHEC passes through the human GI tract to its site of colonization in the large intestine, it faces a multitude of host assaults including acute acid stress in the stomach, bile salt stress and cationic antimicrobial peptide exposure in the small intestine, and short chain fatty acid (SCFA) stress in the large intestine. The research carried out in this doctoral dissertation focuses on understanding how EHEC senses chemical cues from the host’s innate immune responses and how this knowledge can be exploited to develop effective antimicrobial strategies. Our findings successfully demonstrate that a novel antimicrobial peptide ameliorates infection in a mouse model of infection by enhancing acid-induced pathogen killing during gastric passage, and that the DNAbinding protein, Dps, plays a significant role in protecting EHEC against peptide killing. Moreover, this research successfully shows that varying concentrations of SCFAs result in differential modulation of EHEC virulence – a finding that contributes to our understanding of the role of diet and commensal flora in host susceptibility to infection. Together the findings of this research demonstrate how the selected innate host defences throughout the human GI tract can be exploited and/or manipulated to effectively prevent infection by the human pathogen EHEC.

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Draft Genome Sequence of Citrobacter rodentium DBS100 (ATCC 51459), a Primary Model of Enterohemorrhagic Escherichia coli Virulence

Cited by 6 publications

References 5 publications

The Virulence Effect of CpxRA in Citrobacter rodentium Is Independent of the Auxiliary Proteins NlpE and CpxP

The Virulence Effect of CpxRA in Citrobacter rodentium Is Independent of the Auxiliary Proteins NlpE and CpxP

Scalable Reporter Assays to Analyze the Regulation of stx2 Expression in Shiga Toxin-Producing Enteropathogens

Understanding and exploiting the response of EHEC O157:H7 to human gastrointestinal chemical signals

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