Filter Glossary


  • Overview


    Escherichia coli (E. coli) bacteria are typically found in the intestinal tract of healthy individuals and animals. While most strains of E. coli are harmless or only cause mild diarrhea, certain strains like E. coli O157:H7 can result in severe symptoms such as intense abdominal cramping, bloody diarrhea, and vomiting.

    Exposure to E. coli can occur through contaminated water or food, particularly raw vegetables and undercooked ground beef. In most cases, healthy adults are able to recover from E. coli O157:H7 infection within a week. However, young children and elderly individuals are at a greater risk of developing a potentially life-threatening form of kidney failure as a result of the infection.

  • Symptoms


    The manifestation of E. coli O157:H7 infection is commonly observed after a period of three to four days from initial exposure to the bacteria. However, it is possible to experience symptoms ranging from one day to over a week after the exposure. Some common indicators of this infection include diarrhea, which can vary from mild and watery to severe and accompanied by blood, as well as stomach cramps, pain or tenderness, and in some cases, nausea and vomiting.

  • When to see a doctor


    Abnormal symptoms may be a warning sign of potential dangerous diseases. Please contact our team of doctors immediately for detailed advice and update the most accurate and appropriate health care method.

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  • Causes


    Only certain strains of E. coli are capable of causing diarrhea, among them being the E. coli O157:H7 strain which belongs to a subgroup that produces a potent toxin capable of damaging the lining of the small intestine. This damage can result in bloody diarrhea. Ingesting this particular strain of bacteria leads to an E. coli infection, and unlike other bacteria that cause diseases, it only takes a small amount of E. coli to cause an infection. As a result, consuming an undercooked hamburger or ingesting contaminated pool water can lead to illness. Potential sources of exposure to this bacterium include contaminated food or water, as well as person-to-person contact.

    Sources of Contamination:

    1. Foodborne Transmission:
      • E. coli infections are commonly contracted through consuming contaminated food items, including:
      • Ground beef: The meat can become contaminated during slaughter and processing, with ground beef being particularly risky due to mixing meat from multiple animals.
      • Unpasteurized milk: Raw milk may carry E. coli bacteria from a cow’s udder or milking equipment.
      • Fresh produce: Runoff from cattle farms can taint the fields where vegetables like spinach and lettuce are cultivated, making them susceptible to contamination.
    2. Waterborne Transmission:
      • Human and animal feces can contaminate ground and surface water, including irrigation sources. Although public water systems typically treat water with chlorine, ultraviolet light, or ozone to eliminate E. coli, some outbreaks have been linked to contaminated municipal water supplies. Private wells, particularly in rural areas, pose a higher risk as they lack proper disinfection methods. Infections can also occur through contact with contaminated water in swimming pools and lakes.
    3. Person-to-Person Transmission:
      • E. coli bacteria can spread easily between individuals, especially when infected individuals, particularly young children, fail to practice proper hand hygiene. Family members of infected children are at increased risk. Outbreaks have been documented in settings like petting zoos and animal barns at county fairs, where contact with animals can lead to transmission.
  • Risk factors


    Factors Influencing E. coli Risk:

    1. Age: Certain groups are more susceptible to E. coli-related complications. Young children and older adults face a higher risk of both contracting E. coli infection and developing severe complications.
    2. Weakened Immune Systems: Individuals with compromised immune systems, such as those with AIDS or undergoing immunosuppressive treatments, are more prone to E. coli illness upon exposure.
    3. Food Selection: Specific foods pose greater risks, including inadequately cooked ground beef, unpasteurized dairy products like milk, apple juice, cider, and soft cheeses made from raw milk.
    4. Seasonal Trends: A notable pattern emerges with the majority of U.S. E. coli infections occurring between June and September, though the exact cause remains uncertain.
    5. Reduced Stomach Acid: Stomach acid plays a protective role against E. coli. If you are using medications that decrease stomach acid levels, such as esomeprazole (Nexium), pantoprazole (Protonix), lansoprazole (Prevacid), or omeprazole (Prilosec), your vulnerability to E. coli infections may increase.
  • Prevention


    Minimizing E. coli Exposure:

    1. Preventive Measures: Currently, there is no available vaccine or medication to shield against E. coli infections, although researchers are actively exploring potential vaccines. To decrease your risk of encountering E. coli, take the following steps:
    2. Water Safety: Refrain from ingesting water from pools or lakes. Ensure water safety by avoiding accidental swallowing.
    3. Hand Hygiene: Maintain frequent handwashing to thwart potential E. coli contamination. Effective hand hygiene is crucial in reducing the risk of infection.
    4. Smart Food Choices: Be mindful of your food choices to mitigate exposure. Steer clear of hazardous foods and adopt cautious practices to avoid contamination.
    5. Thorough Cooking: When cooking hamburgers, ensure they reach an internal temperature of 160°F (71°C) to eliminate any potential E. coli bacteria. Rely on a meat thermometer to ensure thorough cooking.
    6. Pasteurized Consumption: Opt for pasteurized milk, juice, and cider. While pasteurization may not be indicated on the label, boxed or bottled room-temperature beverages are typically pasteurized.
    7. Proper Produce Washing: Vigorously clean raw produce to minimize E. coli presence. While washing may not eliminate all bacteria, it reduces the risk. Special attention should be given to leafy greens.
    8. Prevent Cross-Contamination: Prevent cross-contamination by adhering to these practices:
      • Utensil Hygiene: Thoroughly wash knives, cutting boards, and countertops before and after contact with fresh produce or raw meat using hot, soapy water.
      • Separate Handling: Utilize separate cutting boards for raw meat and other foods, such as fruits and vegetables, to prevent cross-contact.
      • Plate Separation: Never place cooked hamburgers on the same plate used for raw patties, ensuring a clear divide to avoid contamination.
      • Effective Handwashing: Implement rigorous handwashing habits after meal preparation, eating, using the restroom, or changing diapers. Promote hand hygiene among children before meals, post-bathroom use, and following animal interaction.
  • *Please note that the information provided in the article is for reference purposes only. It is essential to consult a doctor before applying any of the suggestions mentioned.

Content Details

Medical info from Mayo Clinic, for reference only. Visit Hoan My for better advice.

Last updated on: 06/08/2023