scholarly journals Pathogenicity of an EnterotoxigenicEscherichia coli Hemolysin (hlyA) Mutant in Gnotobiotic Piglets

1998 ◽  
Vol 66 (10) ◽  
pp. 5031-5035 ◽  
Author(s):  
Rodney A. Moxley ◽  
Emil M. Berberov ◽  
David H. Francis ◽  
Jun Xing ◽  
Mahtab Moayeri ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Structural Gene ◽  
Intestinal Infection ◽  
E Coli ◽  
Oral Inoculation ◽  
Gnotobiotic Piglet ◽  
Gnotobiotic Piglets

ABSTRACT Pigs infected with hemolytic F4+ strains of enterotoxigenic Escherichia coli often develop septicemia secondary to intestinal infection. We tested the hypothesis that inactivation of hemolysin would reduce the ability of F4+enterotoxigenic E. coli to cause septicemia in swine following oral inoculation. Inactivation of the hemolysin structural gene (hlyA) did not decrease the incidence of septicemia in the gnotobiotic piglet model.

scholarly journals A NEW MAP LOCATION FOR THE ilvB LOCUS OF ESCHERICHIA COLI

Genetics ◽  
1980 ◽  
Vol 96 (1) ◽  
pp. 59-77
Author(s):  
Thomas C Newman ◽  
Mark Levinthal
Keyword(s):  
Escherichia Coli ◽  
Structural Gene ◽  
Acetolactate Synthase ◽  
Deletion Mapping ◽  
Donor Strain ◽  
E Coli ◽  
Linkage Of Genes ◽  
Map Location ◽  
New Alleles

ABSTRACT We isolated, in E. coli K12, new alleles of the ilvB locus, the structural gene for acetolactate synthase isoenzyme I, and showed them to map at or near the ilvB619 site. The map position of the ilvB locus was redetermined because plasmids containing the ilvC-cya portion of the chromosome did not complement mutations at the ilvB locus. Furthermore, diploids for the ilvEDAC genes formed with these plasmids in an ilvHI background facilitated the isolation of the new ilvB alleles. The ilvB locus was remapped and found to be located at 81.5 minutes, between the uhp and dnaA loci. This location was determined by two- and three-point transductional crosses, deletion mapping and complementation with newly isolated plasmids. One of the new alleles of the ilvB gene is a mu-1 insertion. When present in the donor strain, this allele interferes with the linkage of genes flanking the mu-1 insertion, as well as the linkage of genes to either side of the mu-1 insertion.

Bacteriophages reduce Escherichia coli O157:H7 levels in experimentally inoculated sheep

2009 ◽  
Vol 89 (2) ◽  
pp. 285-293 ◽  
Author(s):  
S J Bach ◽  
R P Johnson ◽  
K. Stanford ◽  
T A McAllister
Keyword(s):  
Escherichia Coli ◽  
Oral Administration ◽  
Coliform Bacteria ◽  
Escherichia Coli O157 ◽  
Fecal Shedding ◽  
Total Coliforms ◽  
E Coli ◽  
Oral Inoculation ◽  
Experimental Treatments ◽  
And Control

Bacteriophage biocontrol has potential as a means of mitigating the prevalence of Escherichia coli O157:H7 in ruminants. The efficacy of oral administration of bacteriophages for reducing fecal shedding of E. coli O157:H7 by sheep was evaluated using 20 Canadian Arcott rams (50.0 ± 3.0) housed in four rooms (n = 5) in a contained facility. The rams had ad libitum access to drinking water and a pelleted barley-based total mixed ration, delivered once daily. Experimental treatments consisted of administration of E. coli O157:H7 (O157), E. coli O157:H7+bacteriophages (O157+phage), bacteriophages (phage), and control (CON). Oral inoculation of the rams with 109 CFU of a mixture of four nalidixic acid-resistant strains of E. coli O157:H7 was performed on day 0. A mixture of 1010 PFU of bacteriophages P5, P8 and P11 was administered on days -2, -1, 0, 6 and 7. Fecal samples collected on 14 occasions over 21 d were analyzed for E. coli O157:H7, total E. coli, total coliforms and bacteriophages. Sheep in treatment O157+phage shed fewer (P < 0.05) E. coli O157:H7 than did sheep in treatment O157. Populations of total coliforms and total E. coli were similar (P < 0.05) among treatments, implying that bacteriophage lysis of non-target E. coli and coliform bacteria in the gastrointestinal tract did not occur. Bacteriophage numbers declined rapidly over 21 d, which likely reduced the chance of collision between bacteria and bacteriophage. Oral administration of bacteriophages reduced shedding of E. coli O157:H7 by sheep, but a delivery system that would protect bacteriophages during passage through the intestine may increase the effectiveness of this strategy as well as allow phage to be administered in the feed.Key words: Escherichia coli O157:H7, bacteriophage, sheep, environment, coliforms

A Comparison of the Survival in Feces and Water of Escherichia coli O157:H7 Grown under Laboratory Conditions or Obtained from Cattle Feces

2006 ◽  
Vol 69 (1) ◽  
pp. 6-11 ◽  
Author(s):  
L. SCOTT ◽  
P. McGEE ◽  
J. J. SHERIDAN ◽  
B. EARLEY ◽  
N. LEONARD
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogen ◽  
Hemorrhagic Colitis ◽  
Contaminated Water ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Cattle Feces ◽  
Oral Inoculation ◽  
Before And After ◽  
Uremic Syndrome

Escherichia coli O157:H7 is an important foodborne pathogen that can cause hemorrhagic colitis and hemolytic uremic syndrome. Cattle feces and fecally contaminated water are important in the transmission of this organism on the farm. In this study, the survival of E. coli O157:H7 in feces and water was compared following passage through the animal digestive tract or preparation in the laboratory. Feces were collected from steers before and after oral inoculation with a marked strain of E. coli O157:H7. Fecal samples collected before cattle inoculation were subsequently inoculated with the marked strain of E. coli O157:H7 prepared in the laboratory. Subsamples were taken from both animal and laboratory-inoculated feces to inoculate 5-liter volumes of water. E. coli O157:H7 in feces survived up to 97 days, and survival was not affected by the method used to prepare the inoculating strain. E. coli O157:H7 survived up to 109 days in water, and the bacteria collected from inoculated cattle were detected up to 10 weeks longer than the laboratory-prepared culture. This study suggests that pathogen survival in low-nutrient conditions may be enhanced by passage through the gastrointestinal tract.

scholarly journals Induction of Cytolytic Anti-Gal Antibodies in α-1,3-Galactosyltransferase Gene Knockout Mice by Oral Inoculation with Escherichia coli O86:B7 Bacteria

2002 ◽  
Vol 70 (11) ◽  
pp. 6215-6222 ◽  
Author(s):  
Karla J. Posekany ◽  
H. Keith Pittman ◽  
John F. Bradfield ◽  
Carl E. Haisch ◽  
Kathryn M. Verbanac
Keyword(s):  
Escherichia Coli ◽  
Gene Knockout ◽  
Small Animal ◽  
Enteric Bacteria ◽  
Cytolytic Activity ◽  
Target Cells ◽  
E Coli ◽  
Oral Inoculation ◽  
Galt Gene ◽  
Gene Knockout Mice

ABSTRACT Naturally occurring antibodies against [Gal α-1,3-Gal] structures (anti-Gal antibodies) are the primary effectors of human hyperacute rejection (HAR) of nonhuman tissue. Unlike most mammals, humans lack a functional α-1,3-galactosyltransferase (GalT) gene and produce abundant anti-Gal antibodies, putatively in response to GalT+ enteric bacteria. GalT knockout (KO) mice have been generated as a small animal model of HAR but inconsistently express anti-Gal antibodies. We hypothesized that enteric exposure of GalT KO mice to live GalT+ bacteria would produce cytolytic anti-Gal antibodies. Naive mice lacking anti-Gal antibodies were orally immunized with 1010 live GalT+ Escherichia coli O86:B7 bacteria and assayed for anti-Gal antibody titer, isotype, and cytolytic activity. Fecal samples were tested for E. coli O86:B7 prior to and after inoculation. In two separate experiments, 77 to 100% (n = 31) of mice developed serum anti-Gal immunoglobulin G (IgG; titer, 1:5 to 1:80) and/or anti-Gal IgM antibodies (titer, 1:5 to 1:1,280) 14 days postinoculation. Induced anti-Gal antibodies caused complement-mediated cytolysis of GalT+ target cells, with extensive cytolysis observed consistently at serum IgM titers of ≥1:320. Absorption with synthetic [Gal α-1,3-Gal] inhibited both antibody binding and cytolysis. E. coli O86:B7 was recovered from stool samples from 83 to 94% of inoculated mice but not from naive mice, thus confirming enteric exposure. These findings demonstrate that oral inoculation with E. coli O86:B7 is a novel and effective method to induce cytolytic anti-Gal antibodies in GalT KO mice and support the premise that enteric exposure to GalT+ bacteria induces anti-Gal antibodies in humans. These studies also suggest a role for GalT KO mice in elucidating anti-Gal responses in microbial immunity.

scholarly journals An Attenuated Escherichia coli K88ac LT(S63K)ΔSTb Efficiently Provides Protection Against Enterotoxigenic Escherichia coli in the Mouse Model

2021 ◽  
Vol 7 ◽  
Author(s):  
Xinyu Zhang ◽  
Shupei Yu ◽  
Darong Cheng ◽  
Yu Feng ◽  
Yuefei Yang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Wild Strain ◽  
Enterotoxigenic Escherichia Coli ◽  
Post Inoculation ◽  
Ileal Loop ◽  
E Coli ◽  
Oral Inoculation ◽  
Attenuated Isolate ◽  
Efficient Protection ◽  
Site Mutagenesis

To develop an attenuated vaccine candidate against K88ac enterotoxigenic Escherichia coli (ETEC), a novel Escherichia coli (E. coli) K88ac LT(S63K)ΔSTb with LT(S63K) mutation and ST1 deletion was generated using site mutagenesis and λ-Red homologous recombination based on wild paternal ETEC strain C83902. E. coli K88ac LT(S63K)ΔSTb showed very similar fimbriae expression and growth kinetics to the wild strain C83902, but it was significantly attenuated according to the results of a rabbit ligated ileal loop assay and mouse infection study. Oral inoculation with E. coli K88ac LT(S63K)ΔSTb stimulated the mucosa immune response and induced the secretion of IgA to K88ac in the intestines in mice. A challenge experiment revealed that the attenuated strain provided efficient protection against C83902 in the following 7 days and at the 24th day post-inoculation, suggesting that the attenuated isolate could act as an ecological protectant and vaccine in preventing K88ac ETEC.

Single oral inoculation with Escherichia coli (ATCC 25922) stimulates generalised production of nitric oxide in mice

2009 ◽  
Vol 57 (1) ◽  
pp. 127-138 ◽  
Author(s):  
Ana Nemec ◽  
Zlatko Pavlica ◽  
David Crossley ◽  
Irena Zdovc ◽  
Damijan Eržen ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Escherichia Coli ◽  
Spin Trap ◽  
Oral Route ◽  
No Production ◽  
Paramagnetic Resonance ◽  
E Coli ◽  
Oral Inoculation ◽  
Nos Inhibitors ◽  
Oxide Synthase

Nitric oxide (NO) production was investigated in the lungs, thoracic aorta, heart, liver, spleen, kidneys and brain of mice inoculated orally withEscherichia coliATCC 25922. Detection of NO was performed by electron paramagnetic resonance (EPR) using diethyldithiocarbamate (DETC) spin trap. Nitric oxide synthase (NOS) inhibitors [nonselective: L-NAME and inducible NOS (iNOS) selective: 1400W] were used to determine the source of NO. Spin-trap only and untreated mice were included as controls. Within 2.5 hours (h) of a single oral inoculation withE. colihalf of the animals had increased NO levels in all investigated organs. Thereafter the signals dropped before increasing again to reach maximal median values by 25 h in all organs of all inoculated mice. The most intense response occurred in livers, followed by aorta and lungs. Early (2.5 h) inhibition of the signal was achieved using both NOS inhibitors. L-NAME was also effective at 25 h, while 1400W-treated mice had increased NO levels beyond 7 h. The generalised increase in NO production in the short and longer term indicates a host response toE. coliadministered by the oral route of infection.

scholarly journals Pilus-Mediated Adherence of Haemophilus influenzae to Human Respiratory Mucins

2000 ◽  
Vol 68 (6) ◽  
pp. 3362-3367 ◽  
Author(s):  
Martin Kubiet ◽  
Reuben Ramphal ◽  
Allan Weber ◽  
Arnold Smith
Keyword(s):  
Escherichia Coli ◽  
Haemophilus Influenzae ◽  
Lung Disease ◽  
Gene Cluster ◽  
Otitis Media ◽  
Structural Gene ◽  
Chronic Lung Disease ◽  
Type B ◽  
E Coli

ABSTRACT Haemophilus influenzae, especially the nontypeable strains, are among the most common pathogens encountered in patients with chronic lung disease and otitis media. We and others have demonstrated that respiratory isolates of nontypeable H. influenzae bind to human mucins, but the mechanism of binding is not entirely clear. We have therefore examined the role of pili in the adherence of both type b and nontypeable H. influenzae to human respiratory mucins. We used isogenic H. influenzaestrains with a mutation in the structural gene for pilin (hifA), a laboratory H. influenzae strain transformed with a type b pilus gene cluster (from strain C54), antibodies raised against H. influenzae HifA, andEscherichia coli strains carrying a cloned type b pilus gene cluster (from strain AM30) in these studies. All bacteria lacking HifA or the pilus gene cluster had decreased adherence of piliatedH. influenzae to mucins, and Fab fragments of anti-HifA antibodies inhibited the adherence. E. coli strains carrying the cloned type b pilus gene cluster were six to seven times more adhesive than strains carrying the vector. The role of other putative adhesins was not examined and thus cannot be excluded, but these studies support a role for pili in the binding of H. influenzae to human respiratory mucins.

scholarly journals Long Polar Fimbriae Contribute to Colonization by Escherichia coli O157:H7 In Vivo

2004 ◽  
Vol 72 (10) ◽  
pp. 6168-6171 ◽  
Author(s):  
Dianna M. Jordan ◽  
Nancy Cornick ◽  
Alfredo G. Torres ◽  
Evelyn A. Dean-Nystrom ◽  
James B. Kaper ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Parent Strain ◽  
Escherichia Coli O157 ◽  
Intestinal Colonization ◽  
E Coli ◽  
Gnotobiotic Piglets

ABSTRACT The contribution of long polar fimbriae to intestinal colonization by Escherichia coli O157:H7 was evaluated in sheep, conventional pigs, and gnotobiotic piglets. E. coli O157:H7 strains with lpfA1 and lpfA2 mutated were recovered in significantly lower numbers and caused fewer attachment and effacement lesions than the parent strain.

scholarly journals COLONIZATION OF THE MOUSE INTESTINE WITH ESCHERICHIA COLI

1965 ◽  
Vol 122 (4) ◽  
pp. 745-757 ◽  
Author(s):  
Rose Mushin ◽  
Rene Dubos
Keyword(s):  
Escherichia Coli ◽  
Gastrointestinal Tract ◽  
Intestinal Tract ◽  
Intestinal Infection ◽  
Stomach Tube ◽  
E Coli ◽  
Swiss Mice ◽  
Suggestive Evidence ◽  
Enteropathogenic Strain ◽  
Mouse Intestine

Young albino Swiss mice, of the NCS and NCS-D colonies, proved highly susceptible to the establishment of intestinal infection with an enteropathogenic strain of E. coli administered per os or by stomach tube. The period of highest susceptibility was rather short, extending from the day of birth to approximately 2 weeks of age. Adult NCS and NCS-D mice failed to become experimentally colonized with E. coli, even when large doses were administered per os on 3 consecutive days. The extent of colonization of the various parts of the gastrointestinal tract was related to the size of the infective dose. Many of the young mice died within 2 to 3 days following per os infection with large doses of enteropathogenic E. coli. However, practically all the animals which survived cleared their intestinal infection at approximately the same age. For example, in mice infected with 23 x 106 bacteria, colonization of the intestinal tract usually came to an abrupt end when the animals were 24 to 28 days old, irrespective of the age at which they had been infected. There is suggestive evidence that the acquisition of resistance with age, and the ability of adult animals to control the intestinal infection, are related to the development in the gastrointestinal tract of a microbiota which is antagonistic to E. coli.

Mechanisms for Lactobacillus rhamnosus treatment of intestinal infection by drug-resistant Escherichia coli

2020 ◽  
Vol 11 (5) ◽  
pp. 4428-4445 ◽  
Author(s):  
Na Li ◽  
Bing Pang ◽  
Junjun Li ◽  
Guanwen Liu ◽  
Xiaoguang Xu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactobacillus Rhamnosus ◽  
Multiple Drug ◽  
Therapeutic Effects ◽  
Drug Resistant ◽  
Intestinal Infection ◽  
E Coli ◽  
Intestinal Integrity ◽  
Multiple Drug Resistant

Reducing the viability of pathogens may also play an important role for the therapeutic effects of Lactobacillus rhamnosus SHA113 against multiple-drug-resistant E. coli, as well as influencing on the intestinal integrity and functions of animals.

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