Bacillus Cereus
Bacillus cereus (B. cereus) is a microscopic organism that releases harmful toxins. It can cause food poisoning (intestinal B. cereus) or more serious health issues (non-intestinal B. cereus). Most people with food poisoning recover within 24 hours. But you’re at higher risk of complications if you have a weak or compromised immune system.
What is Bacillus cereus?
Bacillus cereus, often abbreviated as B. cereus, is a type of spore-forming bacterium that can only be observed through a microscope due to its minuscule size. It is commonly found in the environment and possesses the ability to produce harmful toxins that can cause illness in humans.
There are two distinct forms of Bacillus cereus, each affecting different parts of the body:
- Intestinal Bacillus cereus: This form leads to food poisoning, and it typically resolves on its own within a short period. However, individuals with weakened or compromised immune systems are at risk of developing more severe symptoms.
- Non-intestinal Bacillus cereus: This variant can result in more serious infections affecting areas outside of the gastrointestinal tract, such as the eyes, respiratory system, or wounds. Individuals with compromised immune systems, surgical or traumatic injuries, or indwelling catheters are particularly vulnerable to severe non-intestinal Bacillus cereus infections.
What are the subtypes of intestinal Bacillus cereus?
Intestinal Bacillus cereus primarily causes gastrointestinal issues and food poisoning. There are two subtypes of intestinal Bacillus cereus:
- Enterotoxins (diarrheal syndrome): In this subtype, the toxin is produced in the small intestine after consuming food contaminated with the bacterium or its spores. Symptoms typically manifest within six to 15 hours after ingesting contaminated food, which can include various items such as fish, dairy products, meat, sauces, soups, stews, and vegetables.
- Emetic (vomiting) syndrome: In the emetic subtype, the toxin is present in the food before consumption. Symptoms, such as nausea and vomiting, typically appear within one to six hours after consuming contaminated food. Rice is commonly associated with this type of Bacillus cereus contamination, although it may occur in other starchy foods like pasta, pastry, potatoes, and sushi, as well as cheese.
What is non-intestinal Bacillus cereus?
Non-intestinal Bacillus cereus refers to infections caused by this bacterium outside of the gastrointestinal tract, affecting various body parts including the eyes, respiratory system, and wounds. Non-intestinal Bacillus cereus can be contracted through exposure to contaminated dust, plants, soil, or water.
Who is susceptible to Bacillus cereus?
Bacillus cereus can affect individuals of all ages and ethnic backgrounds. However, the risk of developing non-intestinal Bacillus cereus infections is higher for:
- Newborns.
- Individuals with indwelling catheters.
- People with compromised or weakened immune systems.
- Those with surgical or traumatic wounds.
- Intravenous (IV) drug users.
How common is Bacillus cereus?
Intestinal Bacillus cereus infections, typically associated with food poisoning, are relatively common. It is estimated that there are around 63,400 instances of B. cereus outbreaks each year in the United States.
On the other hand, non-intestinal Bacillus cereus infections are rarer and occur less frequently.
SYMPTOMS AND CAUSES
How does Bacillus cereus cause food poisoning?
Intestinal Bacillus cereus-related food poisoning typically arises from consuming foods that have been stored at room temperature. Interestingly, reheating the contaminated food does not eliminate the risk of illness. This occurs because Bacillus cereus in the intestines forms spores that release toxins. These spores can multiply at room temperature, and when ingested, the toxins induce symptoms like vomiting or diarrhea.
What are the symptoms of food poisoning caused by Bacillus cereus?
Food poisoning from Bacillus cereus can result in two distinct sets of symptoms:
- Enterotoxins (diarrheal syndrome) symptoms include:
- Abdominal pain.
- Stomach cramps.
- Watery diarrhea.
- Emetic (vomiting) syndrome symptoms include:
- Nausea.
- Vomiting.
How does Bacillus cereus cause non-intestinal illnesses?
Non-intestinal illnesses caused by Bacillus cereus occur when its spores enter the body and release toxins. These spores can be acquired through various means, including:
- Contaminated hospital equipment, such as catheters.
- Infected wounds.
- Inhalation of contaminated dust.
- Hospital outbreaks of infections.
Non-intestinal Bacillus cereus infections can lead to a range of health issues, including bacteremia (bacteria in the bloodstream), endophthalmitis (eye infection), brain abscess, cellulitis, endocarditis, meningitis, osteomyelitis, and pneumonia.
What are the symptoms of non-intestinal illnesses caused by Bacillus cereus?
The symptoms of non-intestinal Bacillus cereus infections vary depending on the type of infection. Endophthalmitis, a severe eye infection, can exhibit symptoms such as eye pain, fatigue, fever, increased white blood cell count (leukocytosis), impaired vision, redness of the eye, and ring-shaped corneal ulcers. Severe cases of endophthalmitis can lead to permanent vision loss.
DIAGNOSIS AND TESTS
How is intestinal Bacillus cereus diagnosed?
The diagnosis of Bacillus cereus-related food poisoning can be confirmed by isolating a significant quantity (greater than or equal to 100,000 organisms per gram) of B. cereus from the implicated food source. Healthcare providers will inquire about symptoms and recent meals, perform a physical examination, and may conduct tests on samples of both the suspected contaminated food and the patient’s stool or vomit. In cases of diarrheal syndrome, blood tests may also be employed to detect the presence of the toxin.
How is non-intestinal Bacillus cereus diagnosed?
The diagnosis of non-intestinal Bacillus cereus infections involves various methods depending on the specific condition. Common diagnostic approaches include blood cultures to detect bacteria in the bloodstream, routine cultures, and Gram staining to identify bacteria in body fluids like vitreous fluid (for endophthalmitis). These tests aim to confirm the presence of Bacillus cereus in the affected area.
MANAGEMENT AND TREATMENT
How is intestinal Bacillus cereus treated?
Most cases of food poisoning related to Bacillus cereus resolve on their own within 24 hours. Treatment typically involves:
- Resting and allowing the body to recover.
- Increasing fluid intake to prevent dehydration.
In severe cases with prolonged diarrhea or vomiting, healthcare providers may recommend intravenous (IV) fluids to rehydrate the patient.
How is non-intestinal Bacillus cereus treated?
The treatment of non-intestinal Bacillus cereus infections varies depending on the specific condition. Typically, antibiotics are prescribed to combat the bacteria. However, it’s important to note that Bacillus cereus has shown resistance to certain antibiotics. Treatment decisions will depend on the type and severity of the infection, and healthcare providers will choose appropriate antibiotics accordingly.
How can I reduce my risk of intestinal Bacillus cereus?
To lower the risk of intestinal Bacillus cereus-related food poisoning, it’s important to practice safe food handling and storage. Here are some steps to reduce the risk:
- Rapidly cool cooked foods that won’t be consumed immediately to a temperature below 41 degrees Fahrenheit (41°F) within six hours.
- Maintain cold foods at temperatures below 41°F.
- Keep hot foods at temperatures above 135 degrees Fahrenheit (135°F).
- Ensure that reheated food reaches a minimum temperature of 165 degrees Fahrenheit (165°F).
- Discard any food suspected of bacterial contamination.
How can I reduce my risk of non-intestinal Bacillus cereus?
Reducing the risk of non-intestinal Bacillus cereus infections involves the following precautions:
- Adhere to proper and frequent handwashing to reduce the risk of infection.
- Seek treatment for any underlying medical conditions that compromise the immune system.
- Avoid intravenous (IV) drug use.
- Promptly seek medical care for any wounds or injuries to prevent infection.
What can I expect if I have Bacillus cereus?
For individuals with intestinal Bacillus cereus, the prognosis is typically excellent, and most people recover fully. The illness tends to be self-limiting and resolves quickly.
In contrast, non-intestinal Bacillus cereus infections can lead to severe complications, including death or the development of various health issues. The outcome depends on factors such as the speed of treatment, the severity of the infection, and the presence of underlying medical conditions.
What is the outlook if I have Bacillus cereus?
The outlook for individuals with intestinal Bacillus cereus is generally positive, with a full recovery expected in most cases.
For those with non-intestinal Bacillus cereus infections, the prognosis varies and depends on several factors, including how promptly treatment is initiated, the seriousness of the infection, and the presence of underlying health conditions.
Are there other conditions that may put me at higher risk of complications?
Individuals with compromised immune systems are at a higher risk of experiencing complications from Bacillus cereus infections. Additionally, the prognosis may be less favorable in cases where:
- Newborns are affected.
- Hospitalization is required.
- Antibiotics for non-intestinal infections are not promptly initiated.
- Underlying conditions, such as hematologic malignancies (e.g., leukemia, lymphoma, or multiple myeloma), liver disease, neutropenia, or corticosteroid use, are present.
How do I take care of myself with Bacillus cereus?
If you have intestinal Bacillus cereus-related food poisoning, self-care measures include:
- Staying well-hydrated by drinking plenty of water.
- Getting adequate rest and allowing your body to recover.
For individuals with non-intestinal Bacillus cereus infections, taking care of oneself involves:
- Maintaining a healthy lifestyle.
- Complying with prescribed medications to manage any underlying medical conditions.
When should I see my healthcare provider?
If you have a weakened or compromised immune system and experience symptoms of food poisoning or a Bacillus cereus infection, it’s essential to seek immediate medical attention.
