Synopsis of enterovirulent Escherichia coli O157:H7

The organism, Escherichia coli 0157:H7 is a Gram negative, facultative anaerobic, rod shaped, sorbitol and glucurionidase negative bacterium that infects the intestinal tract and produces a toxin that affects other parts of the body. Infection and complications: Hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP) are serious illnesses characterized by kidney failure and destruction of the red blood cells leading to anemia, respectively. Young children and the elderly are at greatest risk of developing HUS or TTP fallowing infection. The infection can be acquired by eating contaminated food or water and by contact with fecal material from infected persons or animals. Infective dose is as low as 10 bacterial cells. Foods implicated include raw or undercooked beef, raw milk and raw milk products and unpastuerized fruit juice. Person-to-person spread of the bacteria is possible, however, it is not known if infected persons with no symptoms spread the infection. Symptoms: Symptoms include diarrhea, which is often bloody and recognized for the first time not before 1982, and severe abdominal cramps. The symptoms typically appear from 3 to 8 days, but usually about 3-4 days, following exposure. There is generally little or no fever. Some individuals may become infected but display no symptoms. HUS and thrombotic thrombocytopenic purpura (TTP) have been known to exist for many years, but their association with E coli 0157:H7 infection has only recently been identified. The survival in the host body is conserned, in adults, E coli 0157:H7 infections generally resolve within one week, while in children about one third will carry and shed the organism in their stool for up to three weeks. Treatment: Antibiotic treatment is not only ineffective but also does not alter the severity and duration of diarrhoea, or shorten the period of time someone has E. coli 0157:H7 in this stool. Antibiotic treatment also does not reduce the risk of developing complications after infection rather increase the risk of developing HUS. It is important to prevent and treat dehydration. HUS and TIP require hospitalization for transfusions and kidney dialysis. Prevention: Infection can be prevented through avoiding eating raw or undercooked beef, avoiding drinking unpasteurized milk or milk products, or fruit juices, thorough washing of hands regularly after bowel movements, before and after food preparation and following contact with cattle and their excreta. (Résumé d'auteur