Escherichia coli (E. coli) O157


Escherichia coli O157 (E. coli O157) is a strain of E. coli bacteria that can cause severe food poisoning when ingested by humans. It is a Gram-negative rod-shaped bacterium that is commonly found in the environment and can be found in the intestines of humans and animals, often in contaminated food or water. Infection can cause abdominal cramps, bloody diarrhea, and abdominal pain, and in some cases, it can cause complications such as kidney failure or even death. Careful food safety practices and proper handling of foods can help reduce the risk of infection.


The most common symptoms associated with E. coli O157 infection are abdominal cramps, vomiting, diarrhea (often bloody) and fever. Other than these classic symptoms, more serious complications, such as hemolytic uremic syndrome (HUS), may develop. Symptoms of HUS include decreased frequency of urination, fatigue, paleness, easy bruising, and in the most serious cases, seizures and coma.


The most common cause of E. coli O157 infections is consuming food or water contaminated with the bacteria. This can occur through contact with animal feces that contains the bacteria, eating undercooked ground beef, or consuming unpasteurized milk and juice products. In some cases, the contamination can be spread through contact with an infected person or animal. Poor hygiene practices, such as not thoroughly washing one’s hands after changing a diaper or after contact with animals, can also be a source of E. coli O157 contamination.

Risk factors

The risk factors for Escherichia coli (E. coli) O157 are:

  1. Eating contaminated food, particularly raw fruits and vegetables, undercooked or raw ground beef, contaminated tap water, and unpasteurized milk and juices.
  2. Contact with infected animals, such as cattle, goats, and sheep.
  3. Contact with contaminated surfaces and objects, such as diaper changing areas, toys, and playground equipment.
  4. Having contact with someone who has the infection.
  5. Poor hygiene, such as not washing hands after using the bathroom or before handling food.
  6. Poor sanitation and crowded living conditions.
  7. Swimming in or drinking contaminated water, such as untreated or inadequately treated municipal water supplies.


E. coli O157 infection can be diagnosed by a stool sample or culture test. During the test, a healthcare provider will collect a stool sample from the patient and send it off to a laboratory for testing. The laboratory will then test the sample for the presence of E. coli O157 bacteria. If the bacteria are found, the lab will then perform additional tests to confirm the diagnosis.


Esherichia coli O157 is a type of gram-negative, rod-shaped bacterium commonly found in the intestines of humans and other mammals. This pathogenic strain is notable for its ability to produce a potent toxin called Shiga toxin, as well as its capability to cause severe foodborne illnesses.

E. coli O157 can be further subdivided into a number of different subtypes based on specific genetic characteristics. These subtypes include:

  1. E. coli O157:H7: This is the most common subtype of E. coli O157 and is the one most responsible for causing foodborne illnesses. It is characterized by its ability to produce Shiga toxin and belongs to the 7/8 serogroup.
  2. E. coli O157:HNM: This subtype is characterized by its ability to produce a non-Shiga-toxin-producing form of the bacteria, commonly referred to as Nonmotile Strain (NM). While it is the least common of the O157 subtypes, it has the potential to cause serious infections if ingested.
  3. E. coli O157:H10: This subtype differs from O157:H7 and O157:HNM in that it can produce both Shiga toxin and Nonmotile Strain forms of E. coli. It is mainly associated with humans, livestock, and poultry.
  4. E. coli O157:H6: This subtype is characterized by its lack of Shiga toxin production and is typically found in wild birds, though it can also be found in humans and livestock.


The treatment options for Escherichia coli (E. coli) O157 include the following:

  1. Antibiotic therapy: Antibiotic therapy is the most common treatment for E. coli O157 infections. Commonly used antibiotics include ciprofloxacin, trimethoprim-sulfamethoxazole, amoxicillin, and azithromycin. It is important to finish the entire course of antibiotics, even if symptoms improve.
  2. Supportive care: Supportive care is important in treating E. coli O157 infections. This may include IV fluids to prevent dehydration, pain medications to help with abdominal discomfort, rest, and adequate nutrition.
  3. Antidiarrheal medications: Antidiarrheal medications, such as loperamide, can be used to help control diarrhea in mild cases.
  4. Blood transfusions: Blood transfusions may be necessary in severe cases.
  5. Surgery: Surgery may be necessary in severe cases to remove abscesses or to repair perforated organs.

It is important to seek medical attention as soon as possible if you think you may have an E. coli O157 infection. Early diagnosis and treatment can help prevent complications and reduce the risk of death.


The best way to reduce the risk of E. coli O157 is to practice good hygiene habits. This includes washing hands frequently with soap and water and avoiding contact with contaminated surfaces. Additionally, it is important to cook all meats thoroughly, avoiding the consumption of undercooked or raw food, including unpasteurized juices and raw milk. Additional safety measures include avoiding cross-contamination in the kitchen, such as separating raw meat, poultry and seafood from other items, cleaning all surfaces and utensils after contact with raw meat, and washing all fruits and vegetables before consumption. Lastly, it is important to take extra precaution when visiting petting zoos, avoiding direct contact with animals and washing hands afterwards.

Gender differences?

Yes, there are gender-specific differences in the presentation and management of E. coli O157. Males seem to be more likely to suffer from more severe symptoms than females, such as bloody diarrhea, abdominal pain and nausea. Females, on the other hand, are more likely to be asymptomatic. In terms of management, males are more likely to need extra supportive care to prevent dehydration or electrolyte imbalances from developing, whereas females may just require re-hydration and careful monitoring of their symptoms. It is also important for males to take preventative measures to reduce the risk of recurrent infection, such as avoiding undercooked meats and practicing good hand-washing techniques.


Nutrition plays a very important role in the management of E. coli O157. Proper nutrition is essential to help the immune system fight off any E. coli O157:H7 infection. Eating a balanced diet with plenty of fresh fruits, vegetables, proteins and healthy fats can help fortify the immune system and make it more difficult for the bacteria to establish an infection. Avoiding contaminated food, including raw or undercooked meats, is also essential for preventing an infection. Additionally, it is important to practice good hygiene, such as washing hands before and after preparing food, to help prevent the spread of the bacteria. Finally, nutritional supplements, such as probiotics or enzymes, may be beneficial in helping to manage the effects of an E. coli O157 infection.

Physical Activity

Physical activity can affect Escherichia coli (E. coli) O157 in a variety of ways. For example, physical activity can cause changes to the environment in which the bacteria live. These changes can increase the amount of nutrients available for the bacteria to feed on, potentially enabling the bacteria to grow. Additionally, physical activity can spread bacteria from one host to another, increasing the chance of contact with E. coli O157. Physical activity can also lead to increased perspiration, which in turn can increase the rate of nutrient absorption in the gut, which E. coli O157 can utilize to survive and multiply. Finally, physical activity can lead to increased respiration, providing more oxygen to the environment, which can help E. coli O157 to better survive in hostile environments.

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