What is Escherichia coli (e Coli 0157 H7) (Shiga Toxin-Producing Escherichia Coli O157: H7 )?
The bacteria Shiga toxin-producing Escherichia coli O157: H7, first found in 1982, is a significant problem as it can be spread through food and water, causing symptoms like diarrhea, bloody stools, and a condition called hemolytic-uremic syndrome (HUS) in people. This bacterium, E. coli O157: H7, infects the digestive tract and can cause stomach cramps along with bloody diarrhea. You can catch it if you consume contaminated or undercooked liquids and foods, through a process known as the ‘fecal-oral route’. This bacterium can also spread from person to person, accounting for roughly 11% of infections.
The dreaded properties of E. coli 0157: H7 come from its production of Shiga toxins, which can lead to everything from watery diarrhea to bloody stools. This condition is what doctors refer to as ‘enterohemorrhagic disease’. It can invade your entire body through a condition called hemolytic uremic syndrome. This can cause your red blood cells to break down (hemolytic anemia), lower the amount of platelets which help with blood clotting (thrombocytopenia), or even result in sudden kidney failure (acute renal failure). This syndrome can cause acute, potentially deadly illness, or possibly diseases that persist throughout one’s life.
What Causes Escherichia coli (e Coli 0157 H7) (Shiga Toxin-Producing Escherichia Coli O157: H7 )?
E. coli O157: H7 is a major food-borne bacteria found globally that can cause dangerous conditions such as Haemolytic Uremic Syndrome (HUS) and Thrombotic Thrombocytopenic Purpura (TTP). These are serious illnesses that affect the blood and blood vessels. Studies have found the main carrier of E. coli O157: H7 to be cattle, particularly those in feedlots. The bacteria can thrive in other farm animals too.
The bacteria can be transmitted to humans through several avenues. Eating undercooked meat or dairy products that haven’t been pasteurized properly can lead to E. coli infection. Similarly, coming into contact with contaminated objects carrying this type of E. coli is a common way of getting infected.
Other sources of E. coli infections can include drinking contaminated water, swimming in polluted pools or lakes, consuming poorly cooked meats or poorly washed leafy greens and fruits, drinking unpasteurized juice, or from direct contact with infected animals at petting farms. E. coli contamination on fresh fruits and vegetables can happen because of fecal matter present in the water used for irrigation.
Even though other bacteria can cause haemolytic uremic syndrome (HUS), which damages the blood vessels and affects the kidneys, it is mostly associated with E. coli, particularly E. coli O157: H7. This strain of E. coli has a stronger survival tendency than other strains, which allows it to live through a wide range of tough conditions, often present in the human food chain. This means it can stay in food for a long time, increasing the risk of infection.
Risk Factors and Frequency for Escherichia coli (e Coli 0157 H7) (Shiga Toxin-Producing Escherichia Coli O157: H7 )
The E. coli O157: H7 bacteria is responsible for around 63,000 cases of bloody diarrhea, known as hemorrhagic colitis, every year in the United States. Worldwide, it’s estimated to result in roughly 2.8 million cases per year. This specific type of E. coli can also lead to a serious condition called Hemolytic Uremic Syndrome (HUS), which causes kidney failure, especially in children.
- E. coli O157: H7 causes an estimated 63,000 cases of hemorrhagic colitis annually in the US.
- The number of global cases is around 2.8 million per year.
- The severe E. coli O157: H7-induced HUS can lead to kidney failure, particularly in children.
- While this bacteria can cause diarrheal illness in both adults and children, severe complications are more frequent in children.
- In adults, E. coli O157: H7 infections can sometimes result in HUS and another serious condition, thrombotic thrombocytopenic purpura.
- Outbreaks of this E. coli strain typically happen sporadically and are often linked to contaminated food sources.
Signs and Symptoms of Escherichia coli (e Coli 0157 H7) (Shiga Toxin-Producing Escherichia Coli O157: H7 )
People suffering from this condition usually have sudden attacks of bloody diarrhea and stomach cramps, although they often don’t have a fever. The diarrhea might not be bloody at first and could be watery. Because of the accompanying nausea, vomiting, and heavy diarrhea, patients often feel dehydrated, weak, and notice less urine. It’s essential to know if the patient has any risk factors, like eating raw or undercooked meat or dairy, especially unpasteurized milk, or if they’ve been near farm animals or visited petting zoos or farms.
A physical examination would reveal stomach tenderness as a result of the inflammation and vascular damage in the intestines due to E. coli 0157: H7 Shiga toxin. The stomach pain tends to be more severe than other types of gut inflammation because of the bleeding in the blood vessels. If the person also has signs of dehydration like dryness in the mouth and throat, rapid heart rate, decreased skin plumpness, slow return of skin color when pinched, cold hands and feet, and confusion, that could be a sign of more serious health problems, especially in children.
Testing for Escherichia coli (e Coli 0157 H7) (Shiga Toxin-Producing Escherichia Coli O157: H7 )
If your doctor suspects that you may be suffering from a bacterial infection known as E. coli O157:H7, they will conduct a series of tests to confirm this diagnosis. E. coli is usually found in your stool if you’re infected.
Initially, your doctor will request a blood test, known simply as a complete blood count. This will check for certain conditions such as elevated white blood cells (known as leukocytosis), red blood cell destruction (or hemolysis), and low platelet count (or thrombocytopenia).
A further blood test called a complete metabolic profile will then be done to check your body’s hydration status and whether there are any disturbances in your body’s electrolyte levels or an excess of waste products in the blood, a condition known as uremia. Most people suffering the E. coli O157:H7 will have elevated white blood cell count, usually above 10,000/microL.
Following the blood tests, the doctor will test a sample of your stool. This is because the type of E. coli suspected is usually present in the poop of infected individuals. It is important to know that not all types of E. coli are harmful. Therefore, a special growth medium called sorbitol MacConkey agar is used to distinguish between harmless E. coli and the disease-causing E. coli O157.
Notably, you may be asked if your diarrhea is bloody, as this is a common symptom of E. coli O157:H7 infection. However, not all labs routinely test for E. coli O157:H7, so your physician may have to request this test specifically.
Finally, the presence of E. coli O157:H7 in the stool is confirmed by testing for specific antigens (substances that trigger an immune response) or toxin genes related to this bacteria. This test can be performed using commercially available assays that can detect the Shiga toxins, harmful substances produced by this bacteria, especially in bloody stool samples.
Treatment Options for Escherichia coli (e Coli 0157 H7) (Shiga Toxin-Producing Escherichia Coli O157: H7 )
E. coli 0157: H7 is a type of bacteria that can cause an infection in your gut. Treatment for this infection mainly involves helping you stay hydrated and managing any symptoms that might cause discomfort. In most cases, patients can recover within ten days just by replenishing their body’s fluids.
There was a time when antibiotics were considered a potential treatment for this kind of E. coli infection, but research has shown that they may actually make things worse. They can increase the likelihood of developing a serious condition known as Hemolytic Uremic Syndrome (HUS), which affects the kidneys. This might be because antibiotics can cause a sudden release of a harmful toxin from the E. coli bacteria into your system.
If HUS does develop and become severe, a process called hemodialysis might be recommended. Hemodialysis helps manage any problems with blood volume or electrolyte balance, as well as issues related to acute kidney failure. This procedure works by filtering waste and excess fluid from the blood, essentially performing the kidney’s job when it is not able to.
There is a medication called eculizumab that is sometimes used for E. coli 0157: H7 HUS, but the research on this is still limited. Eculizumab works by blocking a certain process in your immune system, which can help reduce damage to the small blood vessels in your kidneys. However, it’s a very expensive drug primarily used for another rare blood disorder (paroxysmal nocturnal hematuria), and clinicians don’t yet agree about its use in treating HUS related to E. coli. It’s often considered a ‘last resort’ treatment for the most serious cases.
Lastly, while medication called antiperistaltic agents (for example, loperamide or dicyclomine) could be considered because they slow down the movement of the intestines, they’re not advised for E. coli 0157: H7 infections. This is because they could potentially increase the risk of serious complications.
What else can Escherichia coli (e Coli 0157 H7) (Shiga Toxin-Producing Escherichia Coli O157: H7 ) be?
When dealing with a certain dangerous type of E. coli (O157: H7) that causes bloody diarrhea, doctors need to distinguish it from other harmful gut bacteria that cause similar symptoms. These other bacteria are:
- Salmonella
- Shigella
- Campylobacter
- Yersinia
- C. difficile (Clostridium difficile)
The reason that this is important is because using antibiotics can often help patients to recover from these other bacterial infections.
Doctors also need to keep in mind that symptoms like bloody diarrhea can be caused by things other than infections. Some possible non-infectious causes they might consider are:
- Ischemic colitis (inflammation caused by not enough blood flow to the colon)
- Mesenteric ischemia (not enough blood flow to the intestines)
- Crohn’s disease (a type of chronic inflammation of the digestive tract)
- Ulcerative colitis (a type of inflammatory bowel disease that affects the innermost lining of your large intestine (colon) and rectum)
What to expect with Escherichia coli (e Coli 0157 H7) (Shiga Toxin-Producing Escherichia Coli O157: H7 )
Generally, people with a type of bacterial infection in their intestines known as enterohemorrhagic E. coli colitis have a good chance of recovery, especially if they don’t display symptoms beyond diarrhea. However, there’s a complication called Hemolytic Uremic Syndrome (HUS), a serious condition affecting the blood and blood vessels, which can occur in up to 10% of E. coli cases, notably the strain 0157:H7.
This risk is particularly higher for young children, especially those under 5 years old. If they develop HUS complications, the chances of these patients not surviving is about 5%. So, while most patients recover well from E.coli colitis, it’s critical to watch for signs of serious complications and promptly address them with medical care.
Possible Complications When Diagnosed with Escherichia coli (e Coli 0157 H7) (Shiga Toxin-Producing Escherichia Coli O157: H7 )
While most individuals recover from the acute phase of HUS (hemolytic uremic syndrome) linked to bloody diarrhea, they could potentially face long-lasting kidney problems and other complications. These complications can include seizures, diabetes, chronic colitis, and high blood pressure. HUS is most often caused by a strain of bacteria called E. coli O157:H7, presenting most frequently in children under 5 years old and the elderly.
HUS usually appears 5 to 10 days after the start of bloody diarrhea. It is characterized by three main symptoms:
- hemolytic anemia, a condition where red blood cells are destroyed faster than they can be produced,
- acute kidney failure,
- thrombocytopenia, a low platelet count in the blood.
About 10% of children infected with E. coli O157:H7 might develop HUS. {his condition carries a yearly death rate of 5%, and survivors are at a higher risk of developing chronic kidney disease. This strain of E. coli also significantly impact elderly people’s health and life expectancy.
E. coli 0157:H7 infections create more than $400 million in healthcare costs every year in the U.S. Since about 10% of individuals with E. coli 0157:H7 bloody colitis might progress to HUS, preventing these bacterial infections could improve health outcomes and reduce health care costs.
Preventing Escherichia coli (e Coli 0157 H7) (Shiga Toxin-Producing Escherichia Coli O157: H7 )
One way to avoid HUS, a severe kidney disorder, is to reduce the spread of certain harmful bacteria, known as Shiga toxin-producing E. coli, from animals to humans. It is important to keep our food and water safe from these bacteria. This can be done through public health measures like ensuring clean water and proper food handling. Personal hygiene, like handwashing, also plays a big role in preventing the spread of this harmful bacteria. Properly washing hands can help prevent infections and reduce the risk of HUS.
Steps that the public can take to prevent the spread of this harmful bacteria include safe food preparation and properly storing food. Many foodborne illnesses can be prevented through public health education and laws designed to improve food safety. There is also ongoing research on how changing the diets of cows may reduce the spread of E. coli. One study found that cows fed hay instead of grain were less likely to spread harmful bacteria.
In addition, there’s ongoing research on a potential vaccine for humans against this bacteria. The goal is to create a vaccine to avoid its spread, including HUS. Such a vaccine could be particularly important for people living in low-income, high-risk areas, where this disease is more common. The vaccine could also, in turn, provide herd immunity, which occurs when a large part of the population becomes immune to a disease, making its spread less likely, protecting those who are not immune.
