Actually, Escherichia coli is a harmless intestinal inhabitant. However, as an opportunist, this germ is often diagnosed in the medical laboratory. Its distribution, pathogenicity, and even the intended use of E. coli are as variable as the germ itself.
What is Escherichia coli?
Escherichia coli is well known in the human intestinal flora as a source of vitamins, especially vitamin K. The bacterium does not normally cause disease. Click to enlarge. When viewed under a microscope, Escherichia coli is a so-called “gram-negative rod bacterium”. It belongs to the enterobacteria family and is a member of the genus Escherichia. Most bacteria of this genus are motile and have numerous other properties. Among other things, E.coli has so-called “fimbriae” or “pili” with which it can attach itself to human blood cells. But that’s not all: many strains also possess so-called “sex pili”: this allows the effortless transfer of genetic information that can give other bacteria advantages, such as resistance to many antibiotics. Another survival advantage is the active “pumping out” of toxins: For example, certain bacteria within the genus can also remove antibiotics from inside the cell. This germ can exist both in the presence or absence of oxygen; it is “obligate anaerobic”. E.coli therefore colonizes not only the intestine, but also wounds, the urinary bladder, or in the worst case, the blood of some patients in intensive care.
Significance and function
Escherichia coli is just not only villain, but also an important component of the human intestinal flora. So this microbe is very significant for human health and also produces vitamin K.
In newborns, it is even often the first germ to colonize the body. E.coli is therefore even used as a drug, to build up a healthy flora of the intestine after antibiotic therapy. Like, for example, the isolated strain from the intestinal flora of a soldier who was apparently immune to diarrhea. This particular E.coli was not only particularly good at absorbing iron from added food, but also protected its carrier against pathogens that would have caused diarrhea without its presence. But this microbe is not only important to the pharmaceutical industry as a probiotic: with the help of biotechnology, E. coli can be used to produce numerous drugs. For this purpose, foreign genes can be introduced into the bacterial cells of specially bred and completely harmless E. coli, which contain specific information for proteins. These are then produced in the bacterium, synthesized, so to speak. And this is done in large quantities and in optimal compatibility, since E.coli as a component of the human intestinal flora hardly causes allergies.
Diseases
Normally, E.coli is a harmless bacterium. However, as an opportunistic pathogen, it finds small weak spots in the host and produces infections. Uropathogenic E.coli (UPEC), play an important role in uncomplicated urinary tract infections. A danger for newborns is E.coli of the “NMEC” type, which can pass the blood–brain barrier and is thus the trigger for neonatal meningitis. Variants of E.coli with an extended ß-lactamase spectrum (ESBL) are particularly difficult to treat, which is why an antibiotic test (antibiogram) should always be performed in the case of infections with Escherichia coli. The “pathogenic E. coli”, which cause 160 million illnesses worldwide every year and are the cause of death for one million people, occupy a special position in terms of the danger and relevance of these bacteria. Children under the age of five are particularly affected, becoming infected with enteropathogenic E.coli (EPEC) mainly in developing countries. The next large group is Enterotoxic E.coli (ETEC), which very often affects travelers. In this case, the supply of electrolytes is important, because “Montezuma’s revenge” and two different enterotoxins cause watery, extreme diarrhea. Enteroinvasive E.coli (EIEC) produce inflammation and ulcers in the stomach or intestine because they directly invade the cells there. Enterohemorrhagic E.coli (EHEC) are particularly dangerous because their toxin can cause severe food poisoning.Complications such as hemolytic uremic syndrome (HUS) are very feared here because they result in death from kidney failure in 10-30 percent of cases. Pathogen reservoirs are often cattle, whose feces contain one to two percent EHEC bacteria, of which, however, only 10 – 100 germs are sufficient for an infection.
Typical and common intestinal diseases
- Crohn’s disease (chronic inflammatory bowel disease)
- Inflammation of the intestine (enteritis)
- Intestinal polyps
- Intestinal colic
- Diverticula in the intestine (diverticulosis)
