Escherichia coli are widespread gram-negative rod bacteria. Non-pathogenic strains of E. coli are part of the normal intestinal flora of humans. Other strains can cause severe intestinal diseases. These include enterohaemorrhagic E. coli (EHEC), enteropathogenic E. coli (EPEC), enterotoxin-forming E. coli (ETEC), enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC) and diffusely adherent E. coli (DAEC).
Infected humans or animals excrete the pathogens with their faeces. The bacteria are transmitted through direct or indirect contact with contaminated persons, animals or objects and through the ingestion of contaminated, raw, or insufficiently heated food or polluted water. Bacteria can also enter the human digestive tract when bathing in (unchlorinated) waters polluted with faeces.
The ability to produce certain cytotoxins, so-called Shiga toxins (cytotoxic proteins), in particular, are what makes certain E. coli bacteria so malicious. Infection with enterohaemorrhagic E. coli (EHEC), for example, can lead to haemorrhagic colitis and haemolytic uraemia syndrome (HUS). The HUS destroys blood cells and damages kidney function. Acute kidney failure occurs, as well as thrombocytopenia, a lack of thrombocytes in the blood.
The enteropathogenic E. coli (EPEC) strain is often the cause of diarrhoea in infants, which is often fatal in developing countries. Similarly, enterotoxin-forming E. coli (ETEC) bacteria can cause severe watery diarrhoea. The bacteria are toxic and attach to the enterocytes of the small intestine.
Enteroinvasive E. coli (EIEC) can attack the mucous membrane of the large intestine and cause inflammation.
The enteroaggregative E. coli (EAEC) bacteria lead to long-term infections, especially in children. In adults, an infection is often accompanied by inflammation outside the gastrointestinal tract.
Diffusely adherent E. coli (DAEC) also cause diarrhoea.
The incubation period for an E. coli infection is 3 to 4 days on average. An affected person is considered contagious as long as E. coli is in the faeces. In children, the bacteria are in excretions much longer than in adults. Symptoms include bloody watery diarrhoea, nausea, vomiting, and abdominal pain. Bowel inflammation with spasmodic abdominal pain, bloody stool, and partial fever occurs during a severe course of the disease. However, an infection can also be asymptomatic and remain clinically undetected.
E. coli is one of the most frequent causes of bacterial urinary tract infections. But stomach and intestinal infections, respiratory tract and wound infections, as well as, rarely, blood poisoning (sepsis) can be traced back to infections with E. coli. E. coli bacteria are among the most common pathogens of nosocomial infections. Antibiotic resistance to E. coli has increased in recent years.
1.5 hours to 16 months
The necessary spectrum of activity against Escherichia coli is: bactericidal