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How did E. coli become the culprit of diarrhea? Uncovering the pathogenic mechanism of EAEC!
Escherichia coli is a common bacterium in the intestines, but some mutant strains can cause serious diseases, especially diarrhea. Furthermore, enteroaggregative Escherichia coli (EAEC), as an emerging pathogen, has been identified as one of the important causes of diarrhea worldwide. This article will delve into the pathogenicity, symptoms, and transmission routes of EAEC, and alert readers to its potential threats.
Characteristics and pathological mechanisms of EAEC
Enteroaggregative Escherichia coli (EAEC), known for its "stacked brick" attachment pattern, reacts primarily in the human laryngeal epithelial cell system. The pathogenic process of EAEC mainly includes bacterial aggregation and adhesion to the intestinal mucosa, followed by the release of enterotoxins and cytotoxins, which can damage host cells and induce inflammatory responses, ultimately leading to diarrhea.
EAEC is reported to be the second most common cause of traveler's diarrhea after enterotoxigenic Escherichia coli (ETEC) and is particularly prevalent in children.
Transmission routes and symptoms of EAEC
EAEC is primarily transmitted via the fecal-oral route, usually associated with contaminated food and water. Common sources of infection include:
- Contaminated water sources
- Contaminated food (such as beef and unpasteurized dairy products)
- Human-to-human transmission (without proper hand washing)
Symptoms of EAEC usually begin within 8 to 52 hours of infection and include abdominal pain, diarrhea, nausea, and vomiting. Some patients may even be at risk for bloody stools, dehydration, or kidney failure, especially those with weakened immune systems.
Bloody stools were observed primarily in children, and in the 2011 outbreak in Germany, EAEC O104:H4 variants caused diarrhea accompanied by bloody stools.
Diagnosis and treatment of EAEC
EAEC is usually diagnosed by stool culture, supplemented with antibiotic susceptibility testing. This process can take as little as 2 days and as long as several weeks. Recent molecular diagnostic techniques can rapidly detect EAEC within a few hours.
In mild cases, antibiotics are not recommended, but for moderate to severe cases, antibiotics such as azithromycin or ciprofloxacin may be an effective treatment option.
Etiology of EAEC and future challenges
The pathogenic mechanism of EAEC is still not fully understood. Studies have shown that it mainly adheres to the intestinal mucosa through polymeric adhesion factor (AAF) and releases a variety of toxins to promote infection. Due to the genetic diversity of EAEC, it is also quite difficult to understand its pathogenicity.
Historically, E. coli has been known as a pathogen for a hundred years, and EAEC has caused many infections in many parts of the world since it was first discovered in 1987. Especially in developing countries, the risk of EAEC infection remains high due to relatively poor sanitary conditions.
The continued threat of EAEC reflects that global public health remains a challenge, and research on how to effectively prevent and treat EAEC infection is urgently needed. In this case, should we rethink our hygiene habits in daily life to reduce our risk of infection?
