E. coli represents a Gram-negative bacillus that belongs to the family Enterobacteriaceae. It is a facultative anaerobic microorganism, motile, does not produce spores and lives as a normal resident in the human digestive tract. With its virulence factors it can give rise to opportunistic infections in the gastrointestinal and urinary systems. Its antigenic system consists of somatic antigen O, flagellar antigen H and capsular antigen K. E. coli which causes diarrhoea can be divided into six subtypes. Many strains of E. coli become resistant to certain antibiotics. It is transmitted by the feco-oral route, through contaminated water, food (beef) or via surface of various objects. E. coli in the genitourinary system can cause asymptomatic bacteraemia, cystitis, prostatitis, and pyelonephritis. Characteristic symptoms are pain and tingling when urinating, perineal and rectal pain, dysuria, nocturia, and hematuria. The characteristic risk groups are the elderly, women (shorter urethra), diabetics, pregnant women and individuals with a urinary catheter. When gastrointestinal infections are concerned, traveler's diarrhoea associated with fever, vomiting, and nausea are the most commonly observed. The use of antibiotics in general in traveler's diarrhoea shortens the duration of symptoms. E. coli can also cause sepsis and hemolytic-uremic syndrome, and continues to be a major public health problem today, especially in developing countries. Treatment is based on antibiotic therapy according to the antibiogram, although rehydration and electrolyte replacement are performed in instances of diarrhoea. The diagnosis is based on microscopic examination, cultivation, urine culture, polymerase chain reaction, biochemical tests, as well as some newer methods such as mass spectrometry. The role of the nurse / technician (except in direct patient care) is in education or prevention. Patient care is based on adjustment, alleviation of fear, pain and other symptoms, as well as the application of Fowler's position, antipyretics, antiemetics and fluid/electrolyte replacement with the help of infusion solutions (i.e., providing venous route). Likewise, it is pivotal to ensure privacy, adequate diet, implement relaxation and pain distancing techniques. Prevention includes proper hand and genital hygiene, consumption of adequately prepared food and sufficient fluid intake.