Researchers Analyze E. Coli DNA and History to Better Understand E. Coli and, Eventually, Develop a Vaccine

E. coli O157:H7 vs. non-O157 STEC, What’s the Difference?
E. coli O157:H7 vs. non-O157 STEC, What’s the Difference?

Escherichia coli (E. Coli) bacteria causes at least 400,000 deaths, and about 400 million cases of diarrhea each year – this according to scientists in the early stages of research intended to eventually develop an E. Coli vaccine to prevent the roughly 350 strains of E. coli which have been linked to human illnesses and death. According to one of the lead researchers, Astrid von Mentzer, E. Coli is the number one cause of diarrhea in the developing world, and a threat to human health globally. He, along with other researchers from Cardiff University and the University of Gothenburg, have just finished a study of 362 strains of E. Coli in one of the largest studies of its kind.

Each of the strains studied were the cause of illnesses across a set of 20 countries over the last 30 years.

The research is focused on looking at the properties of the different strains of E. Coli, both from analysis of the available data on these illnesses and through whole genome sequencing of each strain. The goal is to identify weaknesses across different strains of E. Coli for the purposes o exploiting those weaknesses – one area of focus, for example, has been on how these strains attach to the lining of the stomach and intestines. With this information, the researchers are hopeful that one day they can develop a vaccine that might prevent such adhesion. Professor Gordon Dougan, one of the authors of the study, noted that strains from Africa, Asia and Americas all demonstrated similar traits in many regards, leading him to assert that the “research strengthens our belief that it is possible to target a broad range of enterotoxigenic Escherichia coli groups with one vaccine.”

At present, there is no vaccine for E. Coli, and in fact routine tests for the presence of many of the strains of E. Coli remain elusive. Even in the U.S., there are only select laboratories that can properly identify each strain of Shiga Toxin producing E. Coli, with most testing (both in inspection of food and stool testing of suspected victims) focusing on E. Coli O157:H7, and to a lesser degree E. Coli O121, the common Shiga Toxin producing E. coli that account for the majority of food borne illness E. Coli outbreaks in the U.S.

E. Coli Bacteria: Onset, Duration and Sources

E. coli bacteria is located in the digestive tracts of most mammals, including humans. And while many of the strains are harmless, there is a group of these bacteria that cause diarrhea, dehydration, and can lead to Hemolytic Uremic Syndrome (HUS), which can be fatal. The strains of E. Coli that produce toxins, including Shiga Toxin, cause mild to severe diarrhea, stomach cramps, nausea and vomiting. In the acute cases, the diarrhea is accompanied by blood, which can lead to anemia and kidney failure.

The symptoms can begin within hours or may not present for three to four days – on rare occasions, onset may not take place for a full week. Onset depends on the amount of the pathogen consumed, the health of the victim, and other environmental factors. And while most cases resolve in three to seven days following the onset of symptoms, in many cases they last for weeks or even months. And some victims ill developed ongoing illness including irritable bowel disease or irritable bowel syndrome as a result of an acute case of E. Coli food poisoning.

According to Food Safety Layer Ron Simon, most cases of E. coli food poisoning result from consumption of undercooked beef (particularly mince, burgers and meatballs), unpasteurized milk or milk products, or consumption of produce that is contaminated with human of animal feces. “And in nearly every case in the U.S., the contamination, and the resultant illnesses, are preventable through adoption and careful adherence to good food processing and handling guidelines and practices.”


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