Escherichia coli Infection (E. coli Infection)
Escherichia coli (E. coli), is one of many species of bacteria living in the lower intestines of mammals, known as gut flora. When located in the large intestine, it actually assists with waste processing, vitamin K production, and food absorption.
E. coli can generally cause several intestinal and extra-intestinal infections such as urinary tract infections, meningitis, peritonitis, mastitis, septicemia and Gram-negative pneumonia. The enteric E. coli are divided on the basis of virulence properties into enterotoxigenic (ETEC, causative agent of diarrhea in humans, pigs, sheep, goats, cattle, dogs, and horses), enteropathogenic (EPEC, causative agent of diarrhea in humans, rabbits, dogs, cats and horses); enteroinvasive (EIEC, found only in humans), verotoxigenic (VTEC, found in pigs, cattle, dogs and cats); enterohaemorrhagic (EHEC, found in humans, cattle, and goats, attacking porcine strains that colonize the gut in a manner similar to human EPEC strains) and enteroaggregative E. coli (EAggEC, found only in humans).
Urinary tract infections
Although it is more common in female due to the shorter urinary tract, urinary tract infection is seen in both males and females. It is found in roughly equal proportions in elderly men and women. Since bacteria invariably enter the urinary tract through the urethra (an ascending infection), poor toilet habits can predispose to infection (doctors often advise women to "wipe front to back, not back to front") but other factors are also important: (pregnancy in women, prostate enlargement in men) and in many cases the initiating event is unclear. While ascending infections are generally the rule for lower urinary tract infections and cystitis, the same may not necessarily hold for upper urinary tract infections like pyelonephritis which may be hematogenous in origin.
Gastrointestinal
If E. coli bacteria escape the intestinal tract through a perforation (hole or tear, for example from an ulcer, a ruptured appendix, or a surgical error) and enter the abdomen, they usually cause peritonitis that can be fatal without prompt treatment.