By: Kellie Vinal, Ph.D.
Every year, several unfortunate families find themselves either fighting for the life of a child or, tragically, grieving the loss of a child due to anE. coli infection. After several days of non-stop bloody diarrhea, vomiting, and emergency room visits, many children are admitted into the hospital with severe dehydration, or worse, Hemolytic Uremic Syndrome (HUS). Diagnostic laboratory tests confirm these children developed acute kidney failure or other complications from E. coli. A myriad of treatments may be needed, such as dialysis, blood transfusions, platelet transfusions, or potentially even a kidney transplant. Supportive care is required to help the body fight the infection. Some children fall into comas. Others experience severe edema.
Regardless of the source of infection or the symptoms, a child with an E. coli infection is at risk.
What are E. coli?
Escherichia coli (typically abbreviated as E. coli) are bacteria found commonly in the intestines of people and animals, in the environment, and in foods. E. coli are ubiquitous — meaning they are found everywhere — and the group of bacteria they belong to is incredibly diverse. While most E. coli are harmless, some can cause disease ranging from diarrhea to respiratory illness or urinary tract infections. Pathogenic, or disease-causing, E. coli are typically transmitted through contaminated food or water, or through contact with infected people or animals.
Pathogenic E. coli strains are categorized into “pathotypes” depending on the type of disease they cause. There are six pathotypes that are associated with diarrhea, which are typically referred to as diarrheagenic E. coli:
- Shiga toxin-producing coli (STEC)
- Enterotoxigenic coli (ETEC)
- Enteropathogenic coli (EPEC)
- Enteroaggregative coli (EAEC)
- Enteroinvasive coli (EIEC)
- Diffusely adherent coli (DAEC)
In particular, Shiga toxin-producing E. coli, abbreviated as STEC, is most commonly reported in the news as being associated with foodborne outbreaks.
What are Shiga toxin-producing E. coli?
What gives these bacteria the ability to cause such devastating disease is their capability to create a molecular weapon called a Shiga toxin. These toxins can severely damage the lining of the intestines and kidneys. Shiga toxin-producing E. coli (STEC) can also be referred to as verocytotoxic E. coli (VTEC) or enterohemorrhagic E. coli (EHEC). The STEC strain most commonly identified in cases of foodborne E. coli outbreaks is E. coli O157:H7. Certain strains of STEC are capable of causing bloody diarrhea and in some cases, this can progress to hemolytic uremic syndrome (HUS), which causes the kidneys to fail.
Who is at risk for STEC infections? What are the symptoms?
Although any individual can become infected by STEC, the individuals most susceptible to developing severe disease and/or complications are very young (<5) children and the elderly. Symptoms can vary, but typically an infected individual might experience severe stomach cramps, vomiting, fever, and excessive (and sometimes bloody) diarrhea. The CDC recommends that potentially infected individuals seek medical attention if symptoms include high fever, bloody stool, minimal urination, and excessive vomiting that lasts for more than several days.
What is hemolytic uremic syndrome (HUS)?
According to the CDC, approximately 5-10% of individuals who contract a confirmed case of STEC infection can develop a life-threatening complication called hemolytic uremic syndrome (HUS). In a developing case of HUS, an individual might show symptoms including extreme fatigue, loss of pink color in cheeks and eyelids, or decreased frequency of urination. Immediate medical intervention is required in these cases, as the kidneys might stop working altogether or more serious complications could develop. Although some patients recover with medical attention, others might permanently suffer damage or die from their complications.
How do these infections spread?
An infection begins when an individual swallows STEC, which means that a miniscule (typically invisible) amount of human or animal feces has been ingested. This exposure can be transferred to the mouth through consumption of contaminated food, ingestion of unpasteurized milk or juice, ingestion of contaminated water, contact with feces of infected individuals, or contact with cattle or other animals. There have been reports of STEC infection from swallowing lake water, touching animals or the environment at petting zoos or other settings in which animals are on display, and by consuming food prepared by individuals that did not properly wash their hands after using the restroom.
Petting zoos have been implicated in the past for spreading E. coli infection. In these rare cases, the bacteria is transferred from the animal to the child’s hands, and then spread from the child’s hands to their mouth.
How can I prevent a STEC infection?
Know your risks! Individuals at higher risk for foodborne illness are newborns, children, pregnant women, immunocompromised individuals, and the elderly.
It is incredibly important to exercise proper hygiene – especially handwashing. The CDC urges individuals to wash their hands thoroughly after changing diapers or using the restroom, before and after preparing or eating food, after contact with animals or their environments (at petting zoos or farms), before and after preparing bottles for infants or toddlers, and before touching an object that might go into an infant or toddler’s mouth. If soap and water are unavailable, the CDC recommends using hand sanitizer with at least 60% alcohol, though this method is not a completely safe substitute for proper handwashing.
When preparing food, the CDC recommends individuals to follow the four steps of food safety: clean, separate, cook, and chill. When preparing food, make sure to cook meat thoroughly, always use a food thermometer, prevent cross-contamination by thoroughly washing cutting boards and utensils, and avoid unpasteurized products.
When possible, avoid swallowing water while swimming in pools, lakes, or ponds.