تسجيل الدخول

تسجيل

Bacteria , Escherichia coli

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  117

2026-09-27

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Bacteria , Escherichia coli

Several strains of the common intestinal bacterium E. coli may cause diarrhoeal disease in man. One such strain, which occurs naturally in the gut of cattle and other animals, produces verotoxin (or verocytotoxin), a potent cytotoxin. This E. coli strain, usually referred to as verotoxin producing E. coli (VTEC), is geographically wide spread and is associated with life-threatening human diseases that range from bloody diarrhoea to the haemolytic-uraemic syndrome and thrombocytopenic purpura. Young children, especially those from urban areas, are a particularly vulnerable group because of their age and immunological naivety to farmhouse infections. The chemical nature of verotoxin has not yet been elucidated. VTEC strains are characterised through polymerase chain reaction (PCR) and deoxyribonucleic acid (DNA) hybridisation, and by a Vero-cell cytotoxicity assay (Leung et al. 2001). ELISA methods have also been developed for the detection of verotoxin. Other E. coli strains (O157:H7) and other bacterial species produce Shiga toxins, which may produce disease in humans after consumption of undercooked contaminated beef. In humans these toxins may cause haemorrhagic colitis and haemolytic uraemic syndrome. Enzyme immunoassays are available that detect Shiga toxins in diarrhoeal stool samples from humans, and in contaminated beef (Atalla et al. 2000; Hyatt et al. 2001).