scholarly journals THE EFFECIENCY OF ENTERIC LACTOBACILLUS IN PREVENTING HEMORRHAGIC COLITIS AND BLOCKING SHIGA TOXINS PRODUCTIONS IN RATS MODELS INFECTED WITH ENTEROHEMORRHAGIC ESCHERICHIA COLI (EHEC)

2021 ◽  
Vol 52 (6) ◽  
pp. 1346-1355
Author(s):  
SH. A. Al wendawi ◽  
S. M. Al Rekaby
Keyword(s):  
Escherichia Coli ◽  
Infected Animal ◽  
Mononuclear Cells ◽  
Enterohemorrhagic Escherichia Coli ◽  
Hemorrhagic Colitis ◽  
Rodent Models ◽  
Tubular Epithelium ◽  
Shiga Toxins ◽  
L1 And L2

The objective of this study was to investigate the prophylactic roles of human enteric derived Lactobacillus plantarum L1 (Ll) and Lactobacillus paracasei L2 (L2), on EHEC O157:H7 infection in rodent models (In vivo). The Lactobacillus suspensions (L1 and L2) were individually and orally administered to experimental rats at a daily two consecutives of 100 μl (108 CFU/ ml/rat) for up to two weeks.  Thereafter, on the 8th day of experiment rats were orally challenged with one dose infection of EHEC (105 CFU/ml/rat). Animals mortality and illness symptoms have been monitored. There was no fatal EHEC infection in rats that had been pre‑colonized with the Lactobacillus strains, while most of EHEC infected rats were died (90%).  The Stx1 and Stx2 levels were significantly lower (14 and 12 folds) in the L1and L2 pre-inoculated rates respectively, compared with those in the EHEC colonized group. Histological sections were proven the prophylactic roles of L1 and L2, whereas, no effective histological upsets were detected in Lactobacillus + EHEC- colonized rats. The cytopathic symptoms were predominant in kidney and intestinal sections of EHEC infected rats. The kidney sections cytopathy manifested to lining membrane ulceration, infiltration of mononuclear cells and glomerular and tubular epithelium necrosis.  The striking attaching and effacing (A/E) lesions were prominent in intestinal sections of EHEC infected animal models.

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 Human Neutrophils and Their Products Induce Shiga Toxin Production by Enterohemorrhagic Escherichia coli

2001 ◽  
Vol 69 (3) ◽  
pp. 1934-1937 ◽  
Author(s):  
Patrick L. Wagner ◽  
David W. K. Acheson ◽  
Matthew K. Waldor
Keyword(s):  
Escherichia Coli ◽  
Clinical Isolate ◽  
Shiga Toxin ◽  
Toxin Production ◽  
Enterohemorrhagic Escherichia Coli ◽  
Human Neutrophils ◽  
Prophage Induction ◽  
Shiga Toxins ◽  
E Coli

ABSTRACT The Shiga toxins (Stx) are critical virulence factors forEscherichia coli O157:H7 and other serotypes of enterohemorrhagic E. coli (EHEC). These potent toxins are encoded in the genomes of temperate lambdoid bacteriophages. We recently demonstrated that induction of the resident Stx2-encoding prophage in an O157:H7 clinical isolate is required for toxin production by this strain. Since several factors produced by human cells, including hydrogen peroxide (H2O2), are capable of inducing lambdoid prophages, we hypothesized that such molecules might also induce toxin production by EHEC. Here, we studied whether H2O2 and also human neutrophils, an important endogenous source of H2O2, induced Stx2 expression by an EHEC clinical isolate. Both H2O2 and neutrophils were found to augment Stx2 production, raising the possibility that these agents may lead to prophage induction in vivo and thereby contribute to EHEC pathogenesis.

scholarly journals The Locus of Enterocyte Effacement-Encoded Effector Proteins All Promote Enterohemorrhagic Escherichia coli Pathogenicity in Infant Rabbits

2005 ◽  
Vol 73 (3) ◽  
pp. 1466-1474 ◽  
Author(s):  
Jennifer M. Ritchie ◽  
Matthew K. Waldor
Keyword(s):  
Escherichia Coli ◽  
Effector Proteins ◽  
Enterohemorrhagic Escherichia Coli ◽  
Lesion Formation ◽  
Specific Effects ◽  
Genes Encoding ◽  
Organ Specific ◽  
Rabbit Intestine ◽  
Enterocyte Effacement

ABSTRACT The genes encoding the enterohemorrhagic Escherichia coli (EHEC) type III secretion system (TTSS) and five effector proteins secreted by the TTSS are located on the locus of enterocyte effacement (LEE) pathogenicity island. Deletion of tir, which encodes one of these effector proteins, results in a profound reduction (∼10,000-fold) in EHEC colonization of the infant rabbit intestine, but the in vivo phenotypes of other LEE genes are unknown. Here, we constructed in-frame deletions in escN, the putative ATPase component of the TTSS, and the genes encoding the four other LEE-encoded effector proteins, EspH, Map, EspF, and EspG, to investigate the contributions of the TTSS and the translocated effector proteins to EHEC pathogenicity in infant rabbits. We found that the TTSS is required for EHEC colonization and attaching and effacing (A/E) lesion formation in the rabbit intestine. Deletion of escN reduced EHEC recovery from the rabbit intestine by ∼10,000-fold. Although EspH, Map, EspF, and EspG were not required for A/E lesion formation in the rabbit intestine or in HeLa cells, these effector proteins promote EHEC colonization. Colonization by the espH and espF mutants was reduced throughout the intestine. In contrast, colonization by the map and espG mutants was reduced only in the small intestine, indicating that Map and EspG have organ-specific effects. EspF appears to down-regulate the host response to EHEC, since we observed increased accumulation of polymorphonuclear leukocytes in the colonic mucosa of rabbits infected with the EHEC espF mutant. Thus, all the known LEE-encoded effector proteins influence EHEC pathogenicity.

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.

scholarly journals Contributions of O Island 48 to Adherence of Enterohemorrhagic Escherichia coli O157:H7 to Epithelial Cells In Vitro and in Ligated Pig Ileal Loops

2009 ◽  
Vol 75 (18) ◽  
pp. 5779-5786 ◽  
Author(s):  
Xianhua Yin ◽  
Roger Wheatcroft ◽  
James R. Chambers ◽  
Bianfang Liu ◽  
Jing Zhu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Cluster Formation ◽  
Gene Clusters ◽  
Enterohemorrhagic Escherichia Coli ◽  
Wild Type ◽  
The Difference ◽  
Large Clusters

ABSTRACT O island 48 (OI-48) of Escherichia coli consists of three functional gene clusters that encode urease, tellurite resistance (Ter), and putative adhesins Iha and AIDA-1. The functions of these clusters in enterohemorrhagic E. coli (EHEC) O157:H7 infection are unknown. Deletion mutants for these three regions were constructed and evaluated for their ability to adhere to epithelial cells in vitro and in ligated pig ileal loops. Deletion of the Ter gene cluster reduced the ability of the organism to adhere to and form large clusters on IPEC-J2 and HEp-2 cells. Complementation of the mutation by introducing the wild-type ter genes restored adherence and large-cluster formation. Tests in ligated pig ileal loops showed a decrease in colonization by the Ter-negative mutant, but the difference was not significant compared to colonization by the wild type (26.4% ± 21.2% versus 40.1% ± 19.1%; P = 0.168). The OI-48 aidA gene deletion had no effect on adherence in vitro or in vivo. Deletion of the iha and ureC genes had no effect on adherence in vitro but significantly reduced the colonization of EHEC O157:H7 in the ligated pig intestine. These data suggest that Ter, Iha, and urease may contribute to EHEC O157:H7 pathogenesis by promoting adherence of the pathogen to the host intestinal epithelium.

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.

Yogurt Containing Bioactive Molecules Produced by Lactobacillus acidophilus La-5 Exerts a Protective Effect against Enterohemorrhagic Escherichia coli in Mice

2012 ◽  
Vol 75 (10) ◽  
pp. 1796-1805 ◽  
Author(s):  
MOHAMED ZEINHOM ◽  
ANGELA M. TELLEZ ◽  
VERONIQUE DELCENSERIE ◽  
A. M. EL-KHOLY ◽  
S. H. EL-SHINAWY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Protective Effect ◽  
Lactobacillus Acidophilus ◽  
Virulence Genes ◽  
Clinical Manifestations ◽  
Enterohemorrhagic Escherichia Coli ◽  
Bioactive Molecules ◽  
Necrosis Factor Alpha ◽  
In Vivo Effects

An active fraction extracted from Lactobacillus acidophilus La5 cell-free spent medium (LAla-5AF) was incorporated in a dairy matrix and tested to assess its antivirulent effect against enterohemorrhagic Escherichia coli (EHEC). Mice in experimental groups were fed for 4 days with yogurt supplemented with LAla-5AF. On the fifth day, mice were challenged with a single dose (107 CFU per mouse) of E. coli O157:H7. The clinical manifestations of the infection were significantly less severe in mice fed the yogurt supplemented with LAla-5AF. EHEC attachment and colonization was attenuated by LAla-5AF. Tumor necrosis factor alpha production was down-regulated, which might indicate a protective effect in the kidney during EHEC infection. To investigate the mechanisms associated with the in vivo effects observed, LAla-5AF was tested by reverse transcription real-time PCR to confirm its effects on the expression of several virulence genes of EHEC O157. The results showed that these fractions were able to down-regulate several virulence genes of EHEC, including stxB2, qseA, luxS, tir, ler, eaeA, and hlyB.

COMPARISON OF THE CAPACITY OF rhTNF-α AND ESCHERICHIA COLI TO INDUCE PROCOAGULANT ACTIVITY BY BABOON MONONUCLEAR CELLS IN VIVO AND IN VITRO

Shock ◽  
1996 ◽  
Vol 5 (4) ◽  
pp. 274-279 ◽  
Author(s):  
Anguo Li ◽  
Alvin C.K. Chang ◽  
Glenn T. Peer ◽  
Lerner B. Hinshaw ◽  
Fletcher B. Taylor
Keyword(s):  
Escherichia Coli ◽  
Mononuclear Cells ◽  
Procoagulant Activity
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