Escherichia coli, is a kind of bacteria, which lives in the lower intestines of humans and animals. It can cause different diseases under certain conditions, for example, when the immune system is not strong and cannot resist disease from an environmental exposure. Escherichia coli is one of microbial species, which is beneficial for the human`s organism. It has different functions, for example, it helps in digesting, produces some vitamins and prevents colonization by toxic bacteria (Evans et. al, 1996). Though, it is often considered to be harmful for the human`s organism and may cause various illnesses. Many researchers are still working to discover the health hazards of Escherichia coli. It is an interesting fact that the human immune system does not accept E. coli as a foreign object (Frenzen et.al, 2005). On the other hand, these bacteria are known to be the cause of infections in the urinary tract, abdominal cavity, wounds, and hemorrhagic diarrhea. This type of bacteria may be very harmful for people`s health in case of environmental contamination, for example from contaminated food or water. The research asserts that E. coli bacterium is used to indicate safety of drinking water from 1890. It is also an indicator in fecal contamination analysis.
The symptoms of infections and various complications depend on the kind of infection and the strain of Escherichia coli, and may range from mild to severe. Well-known E. coli-causing infections are: appendicitis, ischemic colitis, diabetes mellitus, pancreatitis, and gastroenteritis and neonatal meningitis among others. Treatment of E. coli infection may be started after the first symptoms of the illness have occurred, approximately after ten days of contamination. Escherichia coli is resistible for antibiotics, and according to some available information, they may be even harmful because of the presence of antibiotic resistant organisms. Therefore, treatment of E. coli infection may be individual for a certain disease.