shiga toxin-producing escherichia coli (stec) are food-borne pathogens primarily associated with the consumption of contaminated ground beef and are an important food safety concern worldwide. stec has been found to produce a family of related cytotoxins known as shiga toxins (stxs). shiga toxins have been classified into two major classes, stx1 and stx2. a single strains of stec can produce st...

Escherichia coli Shiga-like toxin I, a close relative of Shiga toxin and a distant relative of the ricin family of plant toxins, inhibits eukaryotic protein synthesis by catalyzing the depurination of adenosine 4324 in 28S rRNA. By comparing the crystallographic structure of ricin with amino acids conserved between the Shiga and ricin toxin families, we identified seven potential active-site re...

Evidence is presented that endocytosis is involved in the transport to the cytosol of the cytotoxin from Shigella dysenteriae 1, Shiga toxin, which acts by removal of a single adenine residue in 28-S ribosomal RNA. Inhibition of endocytosis by ATP depletion of the cells prevented toxin uptake. Exposure of HeLa S3 and Vero cells to toxin at low extracellular pH, where translocation to the cytoso...

Shiga toxin, Shiga-like toxin I (SLT-I) and Shiga-like toxin II (SLT-II) are cell-associated cytotoxins that kill both Vero cells and HeLa cells, whereas Shiga-like toxin II variant (SLT-IIv) is an extracellular cytotoxin that is more cytotoxic for Vero cells than for HeLa cells. The basis for these differences in cytotoxin localization and host cell specificity were examined in this study. The...

Background: Shiga toxin-producing Escherichia coli (STEC) are group of E. coli causing bloody diarrhea. The goal of this survey was to determine the prevalence of multidrug resistant shiga toxin-producing E. coli in cattle meat and its contact surfaces. Methods: Swab samples (n=120) were randomly collected from meat and contact surface of butchery shops in Sharkia province, Egypt. Prevalence o...

Shiga toxin is the main virulence factor of enterohemorrhagic Escherichia coli, a non-invasive pathogen that releases virulence factors in the intestine, causing hemorrhagic colitis and, in severe cases, hemolytic uremic syndrome (HUS). HUS manifests with acute renal failure, hemolytic anemia and thrombocytopenia. Shiga toxin induces endothelial cell damage leading to platelet deposition in thr...

Shiga toxin recognizes a galactose-alpha 1-->4-galactose terminal glycolipid, globotriaosylceramide (Gb3), in sensitive mammalian cells and is translocated by endocytosis to the cytoplasm, where it blocks protein synthesis. To determine if Gb3 is both required and sufficient for toxicity, Gb3 content in cells was altered by blocking key biosynthetic or degradative path enzymes with specific inh...

Virulence of enterohemorrhagic Escherichia coli (EHEC) strains depends on production of Shiga toxins. These toxins are encoded in genomes of lambdoid bacteriophages (Shiga toxin-converting phages), present in EHEC cells as prophages. The genes coding for Shiga toxins are silent in lysogenic bacteria, and prophage induction is necessary for their efficient expression and toxin production. Under ...

BACKGROUND Virulence genes can spread among commensal bacteria through horizontal gene transfer. The bacterium with novel virulence factors may pose a severe threat to public health because of the absence of a management system unlike known pathogens. Especially, when a pathogenic bacterium acquires a new kind of virulence genes, it tends to exhibit stronger virulence. In this study, we analyze...

Cattle are reservoirs for Shiga toxin Escherichia coli (STEC), bacteria shed in animal feces. Humans infected through consumption of contaminated food or water and by direct contact, causing serious disease kidney failure the most vulnerable.