scholarly journals Identification of Antibiotics That Diminish Disease in a Murine Model of Enterohemorrhagic Escherichia coli Infection

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Sabrina Mühlen ◽  
Isabell Ramming ◽  
Marina C. Pils ◽  
Martin Koeppel ◽  
Jana Glaser ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Enterohemorrhagic Escherichia Coli ◽  
Content Type ◽  
Shiga Toxins ◽  
Escherichia Coli Infection ◽  
Uremic Syndrome ◽  
Severity Of The Disease ◽  
Selection Of ◽  
Mild Diarrhea

ABSTRACT Infections with enterohemorrhagic Escherichia coli (EHEC) cause disease ranging from mild diarrhea to hemolytic-uremic syndrome (HUS) and are the most common cause of renal failure in children in high-income countries. The severity of the disease derives from the release of Shiga toxins (Stx). The use of antibiotics to treat EHEC infections is generally avoided, as it can result in increased stx expression. Here, we systematically tested different classes of antibiotics and found that their influence on stx expression and release varies significantly. We assessed a selection of these antibiotics in vivo using the Citrobacter rodentium ϕstx2dact mouse model and show that stx2d-inducing antibiotics resulted in weight loss and kidney damage despite clearance of the infection. However, several non-Stx-inducing antibiotics cleared bacterial infection without causing Stx-mediated pathology. Our results suggest that these antibiotics might be useful in the treatment of EHEC-infected human patients and decrease the risk of HUS development.

scholarly journals Shiga Toxin Gene Loss and Transfer In Vitro and In Vivo during Enterohemorrhagic Escherichia coli O26 Infection in Humans

2007 ◽  
Vol 73 (10) ◽  
pp. 3144-3150 ◽  
Author(s):  
Martina Bielaszewska ◽  
Rita Prager ◽  
Robin Köck ◽  
Alexander Mellmann ◽  
Wenlan Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Gene Loss ◽  
Pulsed Field Gel Electrophoresis ◽  
Enterohemorrhagic Escherichia Coli ◽  
Toxin Gene ◽  
Shiga Toxins ◽  
E Coli

ABSTRACT Escherichia coli serogroup O26 consists of enterohemorrhagic E. coli (EHEC) and atypical enteropathogenic E. coli (aEPEC). The former produces Shiga toxins (Stx), major determinants of EHEC pathogenicity, encoded by bacteriophages; the latter is Stx negative. We have isolated EHEC O26 from patient stools early in illness and aEPEC O26 from stools later in illness, and vice versa. Intrapatient EHEC and aEPEC isolates had quite similar pulsed-field gel electrophoresis (PFGE) patterns, suggesting that they might have arisen by conversion between the EHEC and aEPEC pathotypes during infection. To test this hypothesis, we asked whether EHEC O26 can lose stx genes and whether aEPEC O26 can be lysogenized with Stx-encoding phages from EHEC O26 in vitro. The stx 2 loss associated with the loss of Stx2-encoding phages occurred in 10% to 14% of colonies tested. Conversely, Stx2- and, to a lesser extent, Stx1-encoding bacteriophages from EHEC O26 lysogenized aEPEC O26 isolates, converting them to EHEC strains. In the lysogens and EHEC O26 donors, Stx2-converting bacteriophages integrated in yecE or wrbA. The loss and gain of Stx-converting bacteriophages diversifies PFGE patterns; this parallels findings of similar but not identical PFGE patterns in the intrapatient EHEC and aEPEC O26 isolates. EHEC O26 and aEPEC O26 thus exist as a dynamic system whose members undergo ephemeral interconversions via loss and gain of Stx-encoding phages to yield different pathotypes. The suggested occurrence of this process in the human intestine has diagnostic, clinical, epidemiological, and evolutionary implications.

scholarly journals Enterohemorrhagic Escherichia coli Colonization of Human Colonic EpitheliumIn VitroandEx Vivo

2014 ◽  
Vol 83 (3) ◽  
pp. 942-949 ◽  
Author(s):  
Steven B. Lewis ◽  
Vivienne Cook ◽  
Richard Tighe ◽  
Stephanie Schüller
Keyword(s):  
Escherichia Coli ◽  
Human Colon ◽  
Enterohemorrhagic Escherichia Coli ◽  
Care Needs ◽  
T84 Cells ◽  
Host Cell Membrane ◽  
Content Type ◽  
Colonic Biopsy

EnterohemorrhagicEscherichia coli(EHEC) is an important foodborne pathogen causing gastroenteritis and more severe complications, such as hemorrhagic colitis and hemolytic uremic syndrome. Pathology is most pronounced in the colon, but to date there is no direct clinical evidence showing EHEC binding to the colonic epithelium in patients. In this study, we investigated EHEC adherence to the human colon by usingin vitroorgan culture (IVOC) of colonic biopsy samples and polarized T84 colon carcinoma cells. We show for the first time that EHEC colonizes human colonic biopsy samples by forming typical attaching and effacing (A/E) lesions which are dependent on EHEC type III secretion (T3S) and binding of the outer membrane protein intimin to the translocated intimin receptor (Tir). A/E lesion formation was dependent on oxygen levels and suppressed under oxygen-rich culture conditions routinely used for IVOC. In contrast, EHEC adherence to polarized T84 cells occurred independently of T3S and intimin and did not involve Tir translocation into the host cell membrane. Colonization of neither biopsy samples nor T84 cells was significantly affected by expression of Shiga toxins. Our study suggests that EHEC colonizes and forms stable A/E lesions on the human colon, which are likely to contribute to intestinal pathology during infection. Furthermore, care needs to be taken when using cell culture models, as they might not reflect thein vivosituation.

Selection of In Vivo Expressed Genes of Escherichia coli O157:H7 Strain EDL933 in Ground Meat under Elevated Temperature Conditions

2012 ◽  
Vol 75 (10) ◽  
pp. 1743-1750 ◽  
Author(s):  
ANDREA KROJ ◽  
HERBERT SCHMIDT
Keyword(s):  
Escherichia Coli ◽  
Elevated Temperatures ◽  
Genomic Library ◽  
Transport Processes ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
Ground Meat ◽  
E Coli ◽  
Selection Of

Enterohemorrhagic Escherichia coli O157:H7 strains are important foodborne pathogens that are often transmitted to humans by the ingestion of raw or undercooked meat of bovine origin. To investigate adaptation of this pathogen during persistence and growth in ground meat, we established an in vivo expression technology model to identify genes that are expressed during growth in this food matrix under elevated temperatures (42°C). To improve on the antibiotic-based selection method, we constructed the promoter trap vector pAK-1, containing a promoterless kanamycin resistance gene. A genomic library of E. coli O157:H7 strain EDL933 was constructed in pAK-1 and used for promoter selection in ground meat. The 20 in vivo expressed genes identified were associated with transport processes, metabolism, macromolecule synthesis, and stress response. For most of the identified genes, only hypothetical functions could be assigned. The results of our study provide the first insights into the complex response of E. coli O157:H7 to a ground meat environment under elevated temperatures and establish a suitable vector for promoter studies or selection of in vivo induced promoters in foods such as ground meat.

scholarly journals Cross-Reactive Protection against Enterohemorrhagic Escherichia coli Infection by Enteropathogenic E. coli in a Mouse Model

2011 ◽  
Vol 79 (6) ◽  
pp. 2224-2233 ◽  
Author(s):  
Carla Calderon Toledo ◽  
Ida Arvidsson ◽  
Diana Karpman
Keyword(s):  
Escherichia Coli ◽  
Weight Loss ◽  
Mouse Model ◽  
Enterohemorrhagic Escherichia Coli ◽  
Epec Strain ◽  
Content Type ◽  
E Coli ◽  
Renal Histology ◽  
Escherichia Coli Infection ◽  
Enterocyte Effacement

ABSTRACTEnteropathogenicEscherichia coli(EPEC) and enterohemorrhagicE. coli(EHEC) are related attaching and effacing (A/E) pathogens. The genes responsible for the A/E pathology are carried on a chromosomal pathogenicity island termed the locus of enterocyte effacement (LEE). Both pathogens share a high degree of homology in the LEE and additional O islands. EHEC prevalence is much lower in areas where EPEC is endemic. This may be due to the development of antibodies against common EPEC and EHEC antigens. This study investigated the hypothesis that EPEC infections may protect against EHEC infections. We used a mouse model to inoculate BALB/c mice intragastrically, first with EPEC and then with EHEC (E. coliO157:H7). Four control groups received either a nonpathogenicE. coli(NPEC) strain followed by EHEC (NPEC/EHEC), phosphate-buffered saline (PBS) followed by EHEC (PBS/EHEC), EPEC/PBS, or PBS/PBS. Mice were monitored for weight loss and symptoms. EPEC colonized the intestine after challenge, and mice developed serum antibodies to intimin andE. colisecreted protein B (encoded in the LEE). Prechallenge with an EPEC strain had a protective effect after EHEC infection, as only a few mice developed mild symptoms, from which they recovered. These mice had an increase in body weight similar to that in control animals, and tissue morphology exhibited mild intestinal changes and normal renal histology. All mice that were not prechallenged with the EPEC strain developed mild to severe symptoms after EHEC infection, with weight loss as well as intestinal and renal histopathological changes. These data suggest that EPEC may protect against EHEC infection in this mouse model.

scholarly journals Genomic Comparison of Two O111:H−Enterohemorrhagic Escherichia coli Isolates from a Historic Hemolytic-Uremic Syndrome Outbreak in Australia

2016 ◽  
Vol 84 (3) ◽  
pp. 775-781 ◽  
Author(s):  
Lauren J. McAllister ◽  
Stephen J. Bent ◽  
Nicola K. Petty ◽  
Elizabeth Skippington ◽  
Scott A. Beatson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Sequence Data ◽  
Enterohemorrhagic Escherichia Coli ◽  
Nucleotide Polymorphisms ◽  
Extra Copy ◽  
Content Type ◽  
Shiga Toxin 2 ◽  
Uremic Syndrome ◽  
Insertion Sites

EnterohemorrhagicEscherichia coli(EHEC) is an important cause of diarrhea and hemolytic-uremic syndrome (HUS) worldwide. Australia's worst outbreak of HUS occurred in Adelaide in 1995 and was one of the first major HUS outbreaks attributed to a non-O157 Shiga-toxigenicE. coli(STEC) strain. Molecular analyses conducted at the time suggested that the outbreak was caused by an O111:H−clone, with strains from later in the outbreak harboring an extra copy of the genes encoding the potent Shiga toxin 2 (Stx2). Two decades later, we have used next-generation sequencing to compare two isolates from early and late in this important outbreak. We analyzed genetic content, single-nucleotide polymorphisms (SNPs), and prophage insertion sites; for the latter, we demonstrate how paired-end sequence data can be leveraged to identify such insertion sites. The two strains are genetically identical except for six SNP differences and the presence of not one but two additional Stx2-converting prophages in the later isolate. Isolates from later in the outbreak were associated with higher levels of morbidity, suggesting that the presence of the additional Stx2-converting prophages is significant in terms of the virulence of this clone.

scholarly journals Differential Virulence of Clinical and Bovine-Biased Enterohemorrhagic Escherichia coli O157:H7 Genotypes in Piglet and Dutch Belted Rabbit Models

2011 ◽  
Vol 80 (1) ◽  
pp. 369-380 ◽  
Author(s):  
Smriti Shringi ◽  
Alexis García ◽  
Kevin K. Lahmers ◽  
Kathleen A. Potter ◽  
Sureshkumar Muthupalani ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Severe Disease ◽  
Meat Products ◽  
Developed Countries ◽  
Reservoir Host ◽  
Enterohemorrhagic Escherichia Coli ◽  
Content Type ◽  
Shiga Toxins ◽  
Virulence Potential ◽  
The Developed Countries

ABSTRACTEnterohemorrhagicEscherichia coliO157:H7 (EHEC O157) is an important cause of food and waterborne illness in the developed countries. Cattle are a reservoir host of EHEC O157 and a major source of human exposure through contaminated meat products. Shiga toxins (Stxs) are an important pathogenicity trait of EHEC O157. The insertion sites of the Stx-encoding bacteriophages differentiate EHEC O157 isolates into genogroups commonly isolated from cattle but rarely from sick humans (bovine-biased genotypes [BBG]) and those commonly isolated from both cattle and human patients (clinical genotypes [CG]). Since BBG and CG share the cardinal virulence factors of EHEC O157 and are carried by cattle at similar prevalences, the infrequent occurrence of BBG among human disease isolates suggests that they may be less virulent than CG. We compared the virulence potentials of human and bovine isolates of CG and BBG in newborn conventional pig and weaned Dutch Belted rabbit models. CG-challenged piglets experienced severe disease accompanied by early and high mortality compared to BBG-challenged piglets. Similarly, CG-challenged rabbits were likely to develop lesions in kidney and intestine compared with the BBG-challenged rabbits. The CG strains used in this study carriedstx2and produced significantly higher amounts of Stx, whereas the BBG strains carried thestx2cgene variant only. These results suggest that BBG are less virulent than CG and that this difference in virulence potential is associated with the Stx2 subtype(s) carried and/or the amount of Stx produced.

scholarly journals Enterohemorrhagic Escherichia coli O157:H7 Shiga Toxins Inhibit Gamma Interferon-Mediated Cellular Activation

2012 ◽  
Vol 80 (7) ◽  
pp. 2307-2315 ◽  
Author(s):  
Nathan K. Ho ◽  
Juan C. Ossa ◽  
Uma Silphaduang ◽  
Roger Johnson ◽  
Kathene C. Johnson-Henry ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Tyrosine Phosphorylation ◽  
Cell Activation ◽  
Gamma Interferon ◽  
Enterohemorrhagic Escherichia Coli ◽  
Host Immune System ◽  
Content Type ◽  
Shiga Toxins ◽  
Ifn Γ

ABSTRACTEnterohemorrhagicEscherichia coli(EHEC) serotype O157:H7 is a food-borne pathogen that causes significant morbidity and mortality in developing and industrialized nations. EHEC infection of host epithelial cells is capable of inhibiting the gamma interferon (IFN-γ) proinflammatory pathway through the inhibition of Stat-1 phosphorylation, which is important for host defense against microbial pathogens. The aim of this study was to determine the bacterial factors involved in the inhibition of Stat-1 tyrosine phosphorylation. Human HEp-2 and Caco-2 epithelial cells were challenged directly with either EHEC or bacterial culture supernatants and stimulated with IFN-γ, and then the protein extracts were analyzed by immunoblotting. The data showed that IFN-γ-mediated Stat-1 tyrosine phosphorylation was inhibited by EHEC secreted proteins. Using two-dimensional difference gel electrophoresis, EHEC Shiga toxins were identified as candidate inhibitory factors. EHEC Shiga toxin mutants were then generated and complemented intrans, and mutant culture supernatant was supplemented with purified Stx to confirm their ability to subvert IFN-γ-mediated cell activation. We conclude that while other factors are likely involved in the suppression of IFN-γ-mediated Stat-1 tyrosine phosphorylation,E. coli-derived Shiga toxins represent a novel mechanism by which EHEC evades the host immune system.

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