E. coli serotype O157:H7 infection may cause severe life-threatening symptoms such as hemorrhagic colitis. Most of the symptoms arise due to the Shiga like toxin, which has a genetic similarity with Shiga toxin of Shigella dysenteriae. Why do scientists think that the Origin of the Shiga toxin gene is from Shigella species that cause dysentery, a disease with a similar symptom?
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coli O157:H7. - Scientists have observed that the Shiga-like toxin produced by E. coli O157:H7 shares a high degree of genetic similarity with the Shiga toxin produced by Shigella dysenteriae. This similarity suggests a common origin or a close evolutionary Show more…
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E. coli O157:H7 is a strain that causes food-borne disease and produces Shiga toxin, which is an AB exotoxin. These toxins have multiple B subunits for adhesion and the A subunit to inhibit host cell protein synthesis. are composed of LPS. disrupt host cell adhesion. disrupt membrane of host cells to release nutrients. do not disrupt host cell adhesion.
Shaiju T.
Enterohemorrhagic E. coli will likely cause infantile diarrhea. They cause an inflammatory response. These bacteria have phage genes that produce a toxin similar to tetanospasmin toxin. Like ETEC these E. coli can produce Intimin. The EHEC are also moderately invasive. These organisms can lead to Hemolytic Uremic Syndrome. The toxin can damage blood vessels by binding to GB3 receptor: there are more of these receptors in the renal system.
Madhur L.
The 0157:H7 strain of E. coli is responsible for kidney failure and hemolytic uremic syndrome (HUS). It produces what type of toxin? a. endotoxins similar to staph enterotoxins. b. a superantigen similar to tsst-1. c. an enterohemorrhagic toxin that has similar activities as shiga toxins, but much more serious symptoms. d. an exotoxin similar to bacillus cereus also implicated in food-borne illnesses. Mary Mallon, a.k.a., Typhoid Mary, was identified as the first (but certainly not the only) chronic carrier of Salmonella typhi. Parasitizing her gall bladder, the bacteria probably overcame host defense by doing the following: a. inducing tolerance and suppressing the immune response by interrupting key signaling pathways in the host immune system. b. blocking or interrupting cellular mechanisms to digest or destroy bacteria once in the host cell by interfering with inflammasomal activation. c. resisting host immune response in a manner similar to M. tuberculosis (waxy lipid coating). d. a and b are both correct. Helicobacter pylori was shown to induce ulcers when a research scientist actually drank a bit of the pure culture he had made. What is the most likely mechanism of this pathology? a. the chronic exposure to the organisms focuses the immune system on the infected area of the epithelium causing repeated damage, which results in an ulcer lesion. b. Helicobacter sometimes interrupts the digestion of certain foods, especially spicy ones. c. the lining of the stomach and proximal duodenum are susceptible to ulceration due to constant stress or eating too quickly in some people. d. some people do not have enough probiotics in their diet.
Adi S.
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