scholarly journals Special Issue: Shiga Toxin-Producing Escherichia coli

2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Rodney A. Moxley
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Shiga Toxin ◽  
Diarrheal Disease ◽  
Hemorrhagic Colitis ◽  
Special Issue ◽  
Uremic Syndrome

Globally, Shiga toxin-producing Escherichia coli (STEC) is an important cause of diarrheal disease, most notably hemorrhagic colitis, and post-diarrheal sequela, such as hemolytic-uremic syndrome (HUS) [...]

scholarly journals The Isolation Rate ofEscherichia coli0157:H7 in Toronto and Surrounding Communities

1990 ◽  
Vol 1 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Andrew E Simor ◽  
Christine Watt ◽  
Donald E Low
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Diarrheal Disease ◽  
Hemorrhagic Colitis ◽  
Isolation Rate ◽  
E Coli ◽  
History Of ◽  
Uremic Syndrome ◽  
Stool Specimens ◽  
Differential Medium

Verocytotoxin-producing strains ofEscherichia coli,most often serotype 0157:H7, have been associated with both sporadic and epidemic diarrheal disease in Canada. In order to determine the isolation rate ofE coli0157:H7 in outpatients with diarrhea, all stool specimens submitted for culture to Med-Chem Laboratories in Metropolitan Toronto between June 1988 and September 1989 were cultured on MacConkey-Sorbitol agar in addition to standard enteric media. A total of 46 (0.3%) of 16,125 stool specimens yieldedE coli0157:H7 or verotoxin-producingE coli0157:H−. These isolates came from 31 patients with diarrhea; only 16 (52%) had a history of hemorrhagic colitis and one patient developed hemolytic uremic syndrome. Although MacConkey-Sorbitol agar was useful as a differential medium for detectingE coli0157:H7, 14.5% of all specimens yielded nonsorbitol-fermenting isolates. It is not certain whether the routine use of MacConkey-Sorbitol agar is justified when isolation rates ofE coli0157:117 are very low.

scholarly journals A Novel Tail-Associated O91-Specific Polysaccharide Depolymerase from a Podophage Reveals Lytic Efficacy of Shiga Toxin-Producing Escherichia coli

2020 ◽  
Vol 86 (9) ◽  
Author(s):  
Yibao Chen ◽  
Xiangmin Li ◽  
Shuang Wang ◽  
Lingyu Guan ◽  
Xinxin Li ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Proinflammatory Cytokines ◽  
Shiga Toxin ◽  
Hemorrhagic Colitis ◽  
Content Type ◽  
Increased Risk ◽  
Specific Polysaccharide ◽  
Life Threatening ◽  
Uremic Syndrome

ABSTRACT Shiga toxin-producing Escherichia coli (STEC) strains are important zoonotic foodborne pathogens, causing diarrhea, hemorrhagic colitis, and life-threatening hemolytic uremic syndrome (HUS) in humans. However, antibiotic treatment of STEC infection is associated with an increased risk of HUS. Therefore, there is an urgent need for early and effective therapeutic strategies. Here, we isolated lytic T7-like STEC phage PHB19 and identified a novel O91-specific polysaccharide depolymerase (Dep6) in the C terminus of the PHB19 tailspike protein. Dep6 exhibited strong hydrolase activity across wide ranges of pH (pH 4 to 8) and temperature (20 to 60°C) and degraded polysaccharides on the surface of STEC strain HB10. In addition, both Dep6 and PHB19 degraded biofilms formed by STEC strain HB10. In a mouse STEC infection model, delayed Dep6 treatment (3 h postinfection) resulted in only 33% survival, compared with 83% survival when mice were treated simultaneously with infection. In comparison, pretreatment with Dep6 led to 100% survival compared with that of the control group. Surprisingly, a single PHB19 treatment resulted in 100% survival in all three treatment protocols. Moreover, a significant reduction in the levels of proinflammatory cytokines was observed at 24 h postinfection in Dep6- or PHB19-treated mice. These results demonstrated that Dep6 or PHB19 might be used as a potential therapeutic agent to prevent STEC infection. IMPORTANCE Shiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen worldwide. The Shiga-like toxin causes diarrhea, hemorrhagic colitis, and life-threatening hemolytic uremic syndrome (HUS) in humans. Although antibiotic therapy is still used for STEC infections, this approach may increase the risk of HUS. Phages or phage-derived depolymerases have been used to treat bacterial infections in animals and humans, as in the case of the “San Diego patient” treated with a phage cocktail. Here, we showed that phage PHB19 and its O91-specific polysaccharide depolymerase Dep6 degraded STEC biofilms and stripped the lipopolysaccharide (LPS) from STEC strain HB10, which was subsequently killed by serum complement in vitro. In a mouse model, PHB19 and Dep6 protected against STEC infection and caused a significant reduction in the levels of proinflammatory cytokines. This study reports the use of an O91-specific polysaccharide depolymerase for the treatment of STEC infection in mice.

scholarly journals Whole-genome characterization of hemolytic uremic syndrome-causing Shiga toxin-producing Escherichia coli in Sweden

Virulence ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 1296-1305
Author(s):  
Ying Hua ◽  
Milan Chromek ◽  
Anne Frykman ◽  
Cecilia Jernberg ◽  
Valya Georgieva ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Shiga Toxin ◽  
Whole Genome ◽  
Genome Characterization ◽  
Uremic Syndrome

scholarly journals Infection by verocytotoxin-producing Escherichia coli.

1989 ◽  
Vol 2 (1) ◽  
pp. 15-38 ◽  
Author(s):  
M A Karmali
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Mammalian Cells ◽  
Significant Risk ◽  
Public Health Problem ◽  
Hemorrhagic Colitis ◽  
Commercial Development ◽  
High Biological Activity ◽  
Systemic Complications ◽  
Uremic Syndrome

Verocytotoxin (VT)-producing Escherichia coli (VTEC) are a newly recognized group of enteric pathogens which are increasingly being recognized as common causes of diarrhea in some geographic settings. Outbreak studies indicate that most patients with VTEC infection develop mild uncomplicated diarrhea. However, a significant risk of two serious and potentially life-threatening complications, hemorrhagic colitis and the hemolytic uremic syndrome, makes VTEC infection a public health problem of serious concern. The main reservoirs of VTEC appear to be the intestinal tracts of animals, and foods of animal (especially bovine) origin are probably the principal sources for human infection. The term VT refers to a family of subunit exotoxins with high biological activity. Individual VTEC strains elaborate one or both of at least two serologically distinct, bacteriophage-mediated VTs (VT1 and VT2) which are closely related to Shiga toxin and are thus also referred to as Shiga-like toxins. The holotoxins bind to cells, via their B subunits, to a specific receptor which is probably the glycolipid, globotriosyl ceramide (Gb3). Binding is followed by internalization of the A subunit, which, after it is proteolytically nicked and reduced to the A1 fragment, inhibits protein synthesis in mammalian cells by inactivating 60S ribosomal subunits through selective structural modification of 28S ribosomal ribonucleic acid. The mechanism of VTEC diarrhea is still controversial, and the relative roles of locally acting VT and "attaching and effacing adherence" of VTEC to the mucosa have yet to be resolved. There is increasing evidence that hemolytic uremic syndrome and possibly hemorrhagic colitis result from the systemic action of VT on vascular endothelial cells. The role of antitoxic immunity in preventing the systemic complications of VTEC infection is being explored. Antibiotics appear to be contraindicated in the treatment of VTEC infection. The most common VTEC serotype associated with human disease is O157:H7, but over 50 different VT-positive O:H serotypes have now been identified. The best strategies for diagnosing human VTEC infection include testing for the presence of free VT in fecal filtrates and examining fecal cultures for VTEC by means of deoxyribonucleic acid probes that specify genes encoding VT1 and VT2. Both methods are currently confined to specialized laboratories and await commercial development for wider use. In the meantime, most laboratories should continue to screen for the most common human VTEC serotype, O157:H7, using a sorbitol-containing MacConkey medium.

Outbreak of Shiga Toxin–Producing Escherichia coli (STEC) O104:H4 Infection in Germany Causes a Paradigm Shift with Regard to Human Pathogenicity of STEC Strains

2012 ◽  
Vol 75 (2) ◽  
pp. 408-418 ◽  
Author(s):  
LOTHAR BEUTIN ◽  
ANNETT MARTIN
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Shiga Toxin ◽  
Outbreak Strain ◽  
Fenugreek Seeds ◽  
E Coli ◽  
Aggregative Adherence ◽  
Uremic Syndrome ◽  
Enterocyte Effacement ◽  
The Way

An outbreak that comprised 3,842 cases of human infections with enteroaggregative hemorrhagic Escherichia coli (EAHEC) O104:H4 occurred in Germany in May 2011. The high proportion of adults affected in this outbreak and the unusually high number of patients that developed hemolytic uremic syndrome makes this outbreak the most dramatic since enterohemorrhagic E. coli (EHEC) strains were first identified as agents of human disease. The characteristics of the outbreak strain, the way it spread among humans, and the clinical signs resulting from EAHEC infections have changed the way Shiga toxin–producing E. coli strains are regarded as human pathogens in general. EAHEC O104:H4 is an emerging E. coli pathotype that is endemic in Central Africa and has spread to Europe and Asia. EAHEC strains have evolved from enteroaggregative E. coli by uptake of a Shiga toxin 2a (Stx2a)–encoding bacteriophage. Except for Stx2a, no other EHEC-specific virulence markers including the locus of enterocyte effacement are present in EAHEC strains. EAHEC O104:H4 colonizes humans through aggregative adherence fimbrial pili encoded by the enteroaggregative E. coli plasmid. The aggregative adherence fimbrial colonization mechanism substitutes for the locus of enterocyte effacement functions for bacterial adherence and delivery of Stx2a into the human intestine, resulting clinically in hemolytic uremic syndrome. Humans are the only known natural reservoir known for EAHEC. In contrast, Shiga toxin–producing E. coli and EHEC are associated with animals as natural hosts. Contaminated sprouted fenugreek seeds were suspected as the primary vehicle of transmission of the EAHEC O104:H4 outbreak strain in Germany. During the outbreak, secondary transmission (human to human and human to food) was important. Epidemiological investigations revealed fenugreek seeds as the source of entry of EAHEC O104:H4 into the food chain; however, microbiological analysis of seeds for this pathogen produced negative results. The survival of EAHEC in seeds and the frequency of human carriers of EAHEC should be investigated for a better understanding of EAHEC transmission routes.

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