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Colonic Bleeding
Published in John F. Pohl, Christopher Jolley, Daniel Gelfond, Pediatric Gastroenterology, 2014
Louis Ghanem, Benjamin A Sahn, Petar Mamula
Contaminated food, antibiotic exposure, and immunodeficient states are all associated with increased risk of infectious enterocolitis. Common bacterial pathogens that result in hemorrhagic colitis include Escherichia coli O157:H7, Shigella and Salmonella spp., Campylobacter jejuni, Yersinia enterocolitica, and Clostridium difficile. Entamoeba histolytica is responsible for the highest incidence of parasitic infection in children worldwide. Hemorrhagic cytomegalovirus (CMV) colitis occurs more frequently in patients with congenital or acquired immunodeficiency, most notably underlying chronic colitis in children on long-term therapy with steroids for IBD. Pediatric cases of hemolytic uremic syndrome (HUS) result from shiga toxin-producing enterohemorrhagic Escherichia coli (EHEC) and Shigella in most cases, with pathology predominant in the left and transverse colon. Pseudomembranes, mucosal necrosis, and vascular thrombosis are colonic features of acute and severe HUS.
Waterborne zoonoses *
Published in Jamie Bartram, Rachel Baum, Peter A. Coclanis, David M. Gute, David Kay, Stéphanie McFadyen, Katherine Pond, William Robertson, Michael J. Rouse, Routledge Handbook of Water and Health, 2015
The term enterohaemorrhagic E. coli(EHEC) is used to describe a pathogroup of this species that produce one or more phage-encoded protein toxins (highly related to Shiga toxin of Shigella dysenteria type 1), and are associated with haemorrhagic colitis (HC) in humans. While EHEC have been isolated from a number of animal sources, ruminants and specifically cattle are considered the main animal reservoir of these pathogens. Young age classes of cattle have been shown to shed these organisms in their faeces in large numbers, and EHEC have been isolated from their carcasses at slaughter and from raw beef products such as ground beef. There is also a strong epidemiological link between both sporadic cases and outbreaks of human infections and the consumption of undercooked beef and other foods, including raw vegetables, unpasteurized milk and fruit juices, and water contaminated with ruminant faeces (Gyles 2007, Karmali et al. 2010). EHEC are associated with both systemic and enteric illnesses in humans which range in severity from mild diarrhea to the haemolytic uremic syndrome (HUS). During colonization of the intestine, EHEC release one or more antigenic variant of Shiga toxin (Stx). Once taken up into the bloodstream of the human host, this bipartite protein toxin attaches to and kills the endothelial cells in the small blood vessels of a number of organ systems. The endothelial cell damage promotes coagulation of blood and micro-thrombi formation in target organs such as the kidney. EHEC-associated HUS is characterized by renal failure and hemolytic anemia. EHEC infections are most common in children and sometimes result in death.
Apyrase decreases phage induction and Shiga toxin release from E. coli O157:H7 and has a protective effect during infection
Published in Gut Microbes, 2022
Ida Arvidsson, Ashmita Tontanahal, Karl Johansson, Ann-Charlotte Kristoffersson, Sára Kellnerová, Michael Berger, Ulrich Dobrindt, Diana Karpman
Enterohemorrhagic Escherichia coli (EHEC) cause diarrhea, hemorrhagic colitis, and in certain cases the severe complication hemolytic uremic syndrome (HUS)1 characterized by nonimmune hemolytic anemia, thrombocytopenia, and acute kidney injury with up to 5% mortality. There are no specific or effective treatments for this infection and antibiotic treatment, during the prodromal pre-HUS phase, may increase the risk of developing HUS.2E. coli O157:H7 is the most common clinical isolate of EHEC.1 EHEC infects via oral intake of contaminated food or water and is a noninvasive bacterium.3 After ingestion EHEC colonize the intestine.4 In the intestine, EHEC release virulence factors such as Shiga toxin (Stx).5 During human EHEC infection Stx can be found within intestinal cells6 and massive intestinal inflammation and apoptosis have been reported.7 Similarly, mice inoculated intragastrically with EHEC exhibit goblet cell depletion,8 intestinal inflammation, and apoptosis particularly associated with the presence of Stx.7
Dasatinib-induced colitis: clinical, endoscopic and histological findings
Published in Scandinavian Journal of Gastroenterology, 2022
Kenji Yamauchi, Tomoki Inaba, Hugh Shunsuke Colvin, Ichiro Sakakihara, Kumiko Yamamoto, Koichi Izumikawa, Sakuma Takahashi, Shigetomi Tanaka, Shigenao Ishikawa, Masaki Wato, Midori Ando, Masato Waki
Nishiwaki et al. reported that faecal occult blood testing was performed on 18 patients with CML on dasatinib, and colonoscopy was performed in 10 patients with positive results, of whom six patients (33%) were finally diagnosed with dasatinib-induced haemorrhagic colitis [12]. The incidence of colitis was slightly higher than that in our study, but this is probably because the faecal occult blood test detected mild cases without symptoms. Indeed, no patients in their study had clinically significant symptoms. In addition, in patients with dasatinib-induced colitis without symptoms, dasatinib therapy could be continued for a long time without worsening of colitis [9]. Since the management of patients with symptomatic dasatinib-induced colitis is clinically important, patients with symptoms were enrolled in our study. However, in order to evaluate the true incidence of dasatinib-induced colitis, it may have been more accurate if the subclinical cases were captured through screening, for example by measuring faecal calprotectin.
Butyrate-producing human gut symbiont, Clostridium butyricum, and its role in health and disease
Published in Gut Microbes, 2021
Magdalena K. Stoeva, Jeewon Garcia-So, Nicholas Justice, Julia Myers, Surabhi Tyagi, Madeleine Nemchek, Paul J. McMurdie, Orville Kolterman, John Eid
Studies have also identified C. butyricum as a preventative intervention for gut pathogen infection. Enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes diarrhea and hemorrhagic colitis in humans. Takahashi et al. demonstrated that EHEC O157:H7 growth, toxin production, and adhesion to epithelial cells is inhibited in vitro by CBM 588.77,78 Prophylactic C. butyricum administration to germ-free mice prior to EHEC O157:H7 infection prevented death completely, while administration post infection increased the survival rate from 0% in non-treated controls to 50%.77C. butyricum may also play a preventative role in Clostridium difficile infection. C. difficile is a common pathogen responsible for a large proportion of AAD cases, and in a human study C. butyricum administration was associated with decreased fecal levels of C. difficile as well as the toxin it produces.79 More recently, Woo and colleagues demonstrated that in vitro co-culture of C. difficile with CBM 588 decreased the pathogen’s toxicity in a dose-dependent manner.80 Oka et al. used a non-lethal rat model of C. difficile infection to show a reduced incidence of diarrhea with CBM 588 supplementation.81