scholarly journals Resistance of gnotobiotic Large White and Chinese piglets to in vivo attachment of a K88ab enterotoxigenic Escherichia coli strain

1985 ◽  
Vol 25 (1A) ◽  
pp. 49-60 ◽  
Author(s):  
J. P. CHAPPUIS ◽  
Yvonne DUVAL-IFLAH ◽  
R. DUCLUZEAU ◽  
P. RAIBAUD ◽  
Marie-France OURIET ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Coli Strain ◽  
Enterotoxigenic Escherichia Coli ◽  
Large White

scholarly journals In Vitro and In Vivo Assessment of the Potential of Escherichia coli Phages to Treat Infections and Survive Gastric Conditions

2021 ◽  
Vol 9 (9) ◽  
pp. 1869
Author(s):  
Joanna Kaczorowska ◽  
Eoghan Casey ◽  
Gabriele A. Lugli ◽  
Marco Ventura ◽  
David J. Clarke ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Galleria Mellonella ◽  
Enterotoxigenic Escherichia Coli ◽  
E Coli ◽  
Composite Mixture ◽  
Ph Conditions ◽  
The Stability ◽  
Higher Sensitivity

Enterotoxigenic Escherichia coli (ETEC) and Shigella ssp. infections are associated with high rates of mortality, especially in infants in developing countries. Due to increasing levels of global antibiotic resistance exhibited by many pathogenic organisms, alternative strategies to combat such infections are urgently required. In this study, we evaluated the stability of five coliphages (four Myoviridae and one Siphoviridae phage) over a range of pH conditions and in simulated gastric conditions. The Myoviridae phages were stable across the range of pH 2 to 7, while the Siphoviridae phage, JK16, exhibited higher sensitivity to low pH. A composite mixture of these five phages was tested in vivo in a Galleria mellonella model. The obtained data clearly shows potential in treating E. coli infections prophylactically.

scholarly journals CfaD-Dependent Expression of a Novel Extracytoplasmic Protein from Enterotoxigenic Escherichia coli

2007 ◽  
Vol 189 (14) ◽  
pp. 5060-5067 ◽  
Author(s):  
M. Carolina Pilonieta ◽  
Maria D. Bodero ◽  
George P. Munson
Keyword(s):  
Escherichia Coli ◽  
Binding Sites ◽  
Secretory Pathway ◽  
Dnase I ◽  
Enterotoxigenic Escherichia Coli ◽  
Watery Diarrhea ◽  
Dnase I Footprinting ◽  
Virulence Regulator

ABSTRACT H10407 is a strain of enterotoxigenic Escherichia coli (ETEC) that utilizes CFA/I pili to adhere to surfaces of the small intestine, where it elaborates toxins that cause profuse watery diarrhea in humans. Expression of the CFA/I pilus is positively regulated at the level of transcription by CfaD, a member of the AraC/XylS family. DNase I footprinting revealed that the activator has two binding sites upstream of the pilus promoter cfaAp. One site extends from positions −23 to −56, and the other extends from positions −73 to −103 (numbering relative to the transcription start site of cfaAp). Additional CfaD binding sites were predicted within the genome of H10407 by computational analysis. Two of these sites lie upstream of a previously uncharacterized gene, cexE. In vitro DNase I footprinting confirmed that both sites are genuine binding sites, and cexEp::lacZ reporters demonstrated that CfaD is required for the expression of cexE in vivo. The amino terminus of CexE contains a secretory signal peptide that is removed during translocation across the cytoplasmic membrane through the general secretory pathway. These studies suggest that CexE may be a novel ETEC virulence factor because its expression is controlled by the virulence regulator CfaD, and its distribution is restricted to ETEC.

scholarly journals Draft Genome Sequence of Enterotoxigenic Escherichia coli Strain E24377A, Obtained from a Tribal Drinking Water Source in India

2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Ashok J. Tamhankar ◽  
Sandeep S. Nerkar ◽  
Prashant P. Khadake ◽  
Dadasaheb B. Akolkar ◽  
Sachin R. Apurwa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Genome Sequence ◽  
Draft Genome ◽  
Water Source ◽  
Coli Strain ◽  
Enterotoxigenic Escherichia Coli ◽  
Draft Genome Sequence ◽  
Drinking Water Source

scholarly journals Cooperative Role of Antibodies against Heat-Labile Toxin and the EtpA Adhesin in Preventing Toxin Delivery and Intestinal Colonization by Enterotoxigenic Escherichia coli

2012 ◽  
Vol 19 (10) ◽  
pp. 1603-1608 ◽  
Author(s):  
Koushik Roy ◽  
David J. Hamilton ◽  
James M. Fleckenstein
Keyword(s):  
Escherichia Coli ◽  
Diarrheal Disease ◽  
Vaccine Development ◽  
Enterotoxigenic Escherichia Coli ◽  
Intestinal Colonization ◽  
Content Type ◽  
Heat Labile

ABSTRACTEnterotoxigenicEscherichia coli(ETEC) is an important cause of diarrheal disease in developing countries, where it is responsible for hundreds of thousands of deaths each year. Vaccine development for ETEC has been hindered by the heterogeneity of known molecular targets and the lack of broad-based sustained protection afforded by existing vaccine strategies. In an effort to explore the potential role of novel antigens in ETEC vaccines, we examined the ability of antibodies directed against the ETEC heat-labile toxin (LT) and the recently described EtpA adhesin to prevent intestinal colonizationin vivoand toxin delivery to epithelial cellsin vitro. We demonstrate that EtpA is required for the optimal delivery of LT and that antibodies against this adhesin play at least an additive role in preventing delivery of LT to target intestinal cells when combined with antibodies against either the A or B subunits of the toxin. Moreover, vaccination with a combination of LT and EtpA significantly impaired intestinal colonization. Together, these results suggest that the incorporation of recently identified molecules such as EtpA could be used to enhance current approaches to ETEC vaccine development.

scholarly journals Enteroaggregative Escherichia coli strain in a novel weaned mouse model: exacerbation by malnutrition, biofilm as a virulence factor and treatment by nitazoxanide

2013 ◽  
Vol 62 (6) ◽  
pp. 896-905 ◽  
Author(s):  
David T. Bolick ◽  
James K. Roche ◽  
Raquel Hontecillas ◽  
Josep Bassaganya-Riera ◽  
James P. Nataro ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Body Weight ◽  
Nutritional Status ◽  
Coli Strain ◽  
New Class ◽  
Eaec Strain ◽  
Adults And Children ◽  
Tissue Burden ◽  
Micro Organisms

Enteroaggregative Escherichia coli (EAEC) is increasingly recognized as a common cause of diarrhoea in healthy, malnourished and immune-deficient adults and children. There is no reproducible non-neonatal animal model for longitudinal studies of disease mechanism or therapy. Using two strains of human-derived EAEC to challenge weaned C57BL/6 mice, we explored an in vivo model of EAEC infection in mice, in which disease was monitored quantitatively as the growth rate, stool shedding and tissue burden of organisms; nutritional status was varied, and a new class of therapeutics was assessed. A single oral challenge of EAEC strain 042 resulted in significant growth shortfalls (5–8 % of body weight in 12 days), persistent shedding of micro-organisms in stools [>103.2 c.f.u. (10 mg stool)−1 for at least 14 days] and intestinal tissue burden [~103 c.f.u. (10 mg tissue)−1 detectable up to 14 days post-challenge]. Moderate malnourishment of mice using a ‘regional basic diet’ containing 7 % protein and reduced fat and micronutrients heightened all parameters of infection. Nitazoxanide in subMIC doses, administered for 3 days at the time of EAEC challenge, lessened growth shortfalls (by >10 % of body weight), stool shedding [by 2–3 logs (10 mg stool)−1] and tissue burden of organisms (by >75 % in the jejunum and colon). Thus, weaned C57BL/6 mice challenged with EAEC is a convenient, readily inducible model of EAEC infection with three highly quantifiable outcomes in which disease severity is dependent on the nutritional status of the host, and which is modifiable in the presence of inhibitors of pyruvate ferredoxin oxidoreductase such as nitazoxanide.

Transport of Succinate in Escherichia coli. III. Biochemical and Genetic Studies of the Mechanism of Transport in Membrane Vesicles

1974 ◽  
Vol 52 (10) ◽  
pp. 854-866 ◽  
Author(s):  
Theodore C. Y. Lo ◽  
M. Khalil Rayman ◽  
B. D. Sanwal
Keyword(s):  
Escherichia Coli ◽  
Lactate Dehydrogenase ◽  
Membrane Vesicles ◽  
Coli Strain ◽  
Weight Of Evidence ◽  
Lactate Oxidation ◽  
Dicarboxylate Transport ◽  
Competitive Inhibitors ◽  
Transport Inhibitors

The D-lactate oxidation dependent transport of succinate in membrane vesicles of an Escherichia coli strain lacking succinate dehydrogenase and fumarate reductase is inhibited by several categories of compounds. One category consists of compounds that are electron transport inhibitors (Amytal, Dicumarol, and mercurials), the second of compounds that act as competitive inhibitors of D-lactate dehydrogenase (oxamate and β-chlorolactate), the third of reagents that inhibit the Ca2+–Mg2+-activated ATPase (dicyclohexylcarbodiimide and pyrophosphate), and the fourth of compounds that tap off electrons from the respiratory chain (2,6-dichlorophenolindophenol). None of the succinate transport inhibitors, including mercurials like p-chloromercuribenzoate, interfere with the binding of succinate to the presumed membrane carriers.Membrane preparations from mutants of E. coli lacking D-lactate dehydrogenase are unable to transport succinate in the presence of D-lactate. Whole cells of these mutants, however, take up succinate normally. This observation suggests that D-lactate oxidation is not obligatorily linked in vivo to the uptake of succinate although the possibility is not excluded that transport in such mutants may be linked to some other dehydrogenase. Mutants having altered levels of ATPase, or membrane preparations made from such cells also have greatly reduced capacity to transport succinate. This observation coupled with the finding that ATPase inhibitors block dicarboxylate transport suggests involvement of ATPase in an unknown way in the concentrative uptake of succinate.With the exception of oxamate, β-chlorolactate (competitive inhibitors of D-lactate oxidation), and dicyclohexylcarbodiimide, all of the inhibitors of succinate uptake (including p-chloromercuribenzoate) cause an immediate efflux of preloaded succinate from membrane vesicles. Efflux is also caused by proton conducting reagents. The Km for efflux is 1.9 mM. This value is to be compared with the Km for influx, which is only about 0.02 mM.The weight of evidence favors the view that the active transport of succinate in vesicles occurs as a result of an energization of the membranes by the passage of electrons, although alternate oxidation and reduction of the succinate carrier as a mechanism for transport has not been definitely ruled out.

scholarly journals Genetic Diversity of Heat-Labile Toxin Expressed by Enterotoxigenic Escherichia coli Strains Isolated from Humans

2008 ◽  
Vol 190 (7) ◽  
pp. 2400-2410 ◽  
Author(s):  
M. A. Lasaro ◽  
J. F. Rodrigues ◽  
C. Mathias-Santos ◽  
B. E. C. Guth ◽  
A. Balan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cultured Cells ◽  
Rflp Analysis ◽  
Restriction Enzymes ◽  
Amino Acid Sequences ◽  
Enterotoxigenic Escherichia Coli ◽  
Heat Labile ◽  
Natural Diversity

ABSTRACT The natural diversity of the elt operons, encoding the heat-labile toxin LT-I (LT), carried by enterotoxigenic Escherichia coli (ETEC) strains isolated from humans was investigated. For many years, LT was supposed to be represented by a rather conserved toxin, and one derivative, produced by the reference H10407 strain, was intensively studied either as a virulence factor or as a vaccine adjuvant. Amplicons encompassing the two LT-encoding genes (eltA and eltB) of 51 human-derived ETEC strains, either LT+ (25 strains) only or LT+/ST+ (26 strains), isolated from asymptomatic (24 strains) or diarrheic (27 strains) subjects, were subjected to restriction fragment length polymorphism (RFLP) analysis and DNA sequencing. Seven polymorphic RFLP types of the H10407 strain were detected with six (BsaI, DdeI, HhaI, HincII, HphI, and MspI) restriction enzymes. Additionally, the single-nucleotide polymorphic analysis revealed 50 base changes in the elt operon, including 21 polymorphic sites at eltA and 9 at eltB. Based on the deduced amino acid sequences, 16 LT types were identified, including LT1, expressed by the H10407 strain and 23 other strains belonging to seven different serotypes, and LT2, expressed by 11 strains of six different serotypes. In vitro experiments carried out with purified toxins indicated that no significant differences in GM1-binding affinity could be detected among LT1, LT2, and LT4. However, LT4, but not other toxin types, showed reduced toxic activities measured either in vitro with cultured cells (Y-1 cells) or in vivo in rabbit ligated ileal loops. Collectively, these results indicate that the natural diversity of LTs produced by wild-type ETEC strains isolated from human hosts is considerably larger than previously assumed and may impact the pathogeneses of the strains and the epidemiology of the disease.

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