<P> Nonpathogenic E. coli strain Nissle 1917, also known as Mutaflor, and E. coli O83: K24: H31 (known as Colinfant) are used as probiotic agents in medicine, mainly for the treatment of various gastroenterological diseases, including inflammatory bowel disease . </P> <P> Most E. coli strains do not cause disease, but virulent strains can cause gastroenteritis, urinary tract infections, neonatal meningitis, hemorrhagic colitis, and Crohn's disease . Common signs and symptoms include severe abdominal cramps, diarrhea, hemorrhagic colitis, vomiting, and sometimes fever . In rarer cases, virulent strains are also responsible for bowel necrosis (tissue death) and perforation without progressing to hemolytic - uremic syndrome, peritonitis, mastitis, septicemia, and Gram - negative pneumonia . Very young children are more susceptible to develop severe illness, such as hemolytic uremic syndrome, however, healthy individuals of all ages are at risk to the severe consequences that may arise as a result of being infected with E. coli . </P> <P> Some strains of E. coli for example O157: H7, can produce Shiga toxin (classified as a bioterrorism agent). This toxin causes premature destruction of the red blood cells, which then clog the body's filtering system, the kidneys, causing hemolytic - uremic syndrome (HUS). Unlike most E. coli that naturally live in the gut, the Shiga toxin that causes inflammatory responses in target cells of the gut (the lesions the toxin leaves behind are the reason why bloody diarrhea is a symptom of an Shiga toxin producing E. Coli infection). (In some rare cases (usually in children and the elderly) Shiga toxin producing E. Coli infection may lead to hemolytic uremic syndrome (HUS), which can cause kidney failure and even death . Signs of hemolytic uremic syndrome, include decreased frequency of urination, lethargy, and paleness of cheeks and inside the lower eyelids . In 25% of HUS patients, complications of nervous system occur, which in turn causes strokes due to small clots of blood which lodge in capillaries in the brain . This causes the body parts controlled by this region of the brain not to work properly . In addition, this strain causes the buildup of fluid (since the kidneys do not work), leading to edema around the lungs and legs and arms . This increase in fluid buildup especially around the lungs impedes the functioning of the heart, causing an increase in blood pressure . </P> <P> Uropathogenic E. coli (UPEC) is one of the main causes of urinary tract infections . It is part of the normal microbiota in the gut and can be introduced in many ways . In particular for females, the direction of wiping after defecation (wiping back to front) can lead to fecal contamination of the urogenital orifices . Anal intercourse can also introduce this bacterium into the male urethra, and in switching from anal to vaginal intercourse, the male can also introduce UPEC to the female urogenital system . For more information, see the databases at the end of the article or UPEC pathogenicity . </P>

All members of species escherichia coli belong to the large group known as