Listeria is a bacteria found in soil, water, and some farm animals. With the right conditions, listeria can grow on many different types of food, including fruits, vegetables, meats, and dairy products. When people eat food contaminated with listeria, they can get very sick.
In healthy people, listeria usually results in only mild clinical symptoms, such as fever and diarrhea that self-resolve without treatment. However, in rare cases healthy people can end up in the hospital, especially if they consume excessive amounts of the bacteria. Those that have weakened immune systems, are very young or old, or are pregnant are at higher risk of getting more serious Listeria infections.
Listeria infections most often occur in people with weakened immune systems due to a disease, age, or medication. Elderly and very young people are also at higher risk, as are pregnant women and their unborn babies.
What Are the Symptoms of Listeria Infection?
The signs and symptoms of a listeria infection can range from mild to severe. The most common signs and symptoms of a mild infection include:
- Fever and chills.
- Abdominal pain.
- Diarrhea (non-bloody).
Listeria can spread to the brain through the bloodstream, especially in people who are higher risk of developing infection. In this case, people can develop:
- A stiff neck.
- Loss of balance.
- High fevers.
- Nausea and vomiting.
- Sensitivity to light (photophobia).
Without timely treatment, listeria infection can be fatal.
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How Do Doctors Treat a Listeria Infection?
Doctors treat listeria with antibiotics. The most common treatment for this infection is with the antibiotic ampicillin, which is typically given intravenously in the hospital.
This treatment is safe for most people, including pregnant women. Doctors may also combine ampicillin with another antibiotic in cases of more serious infections. If a patient is allergic to one drug, doctors will choose an alternative antibiotic.
In addition, doctors provide other treatments to reduce symptoms of a listeria infection. These include medications to reduce pain or bring down swelling in the brain.
The Dangers of Listeria in Pregnancy
Women are more than 10 times likely than the general population to get a listeria infection. This is because the immune system’s response is not as robust in pregnancy.
In some cases, pregnant women can pass the infection on to their unborn babies. A listeria infection, called listeriosis, is very dangerous for babies in the womb.
A listeria infection can cause miscarriage, stillbirth, or preterm labor. Babies infected with listeria in the womb may have health problems including seizures, developmental disabilities, or problems with their organs.
Due to the dangers of listeria in pregnancy, pregnant women who have symptoms of listeria infection should see a doctor right away. A doctor can test women for listeria listeria in the blood and give antibiotics. This will reduce the risk of long-term complications for the baby, while also improving the mother’s health.
Experts also recommend pregnant women avoid foods more likely to harbor listeria, like deli meats, sprouts, and soft cheeses. Pregnant women should also steer clear of refrigerated smoked seafood, other cold meats, and pâtés. (Deli meats and hot dogs that are properly microwaved or cooked are safe, as this kills the bacteria). They should also avoid consuming unpasteurized foods.
Pregnant women should also take the precautions described below when cooking, cleaning, and preparing food.
How Can I Prevent a Listeria Infection?
You can prevent a listeria infection by taking precautions to clean, cook, and separate food properly. You can also sign up for alerts for certain food brand recalls due to listeria or the presence of other pathogens.
Here are some steps you can take:
- Wash your hands with soap for at least 20 seconds before handling food, and after touching raw food.
- Wash raw fruits and vegetables and dry them with a clean cloth or paper towel before eating them.
- Keep uncooked meats separate from cooked foods and vegetables, both when storing and preparing food.
- Avoid unpasteurized milk — and cheese made from unpasteurized milk.
- Heat prepared meals and leftovers until they are steaming hot.
- Wash cutting boards, utensils, and kitchen surfaces with soap and hot water.
The UPMC Center for Care of Infectious Diseases provides expert multidisciplinary care. For more information or to make an appointment, call 412-647-7228 or 1-877-788-7228.
About Infectious Diseases
If you have a disease caused by bacteria, fungi, parasite, or virus, the UPMC Center for Care of Infectious Diseases can help. Our team of experts is specially trained in the prevention and treatment of infectious diseases, including of HIV-AIDs, postsurgical and transplant infections, illnesses caused by international travel, and more. We research infectious diseases and participate in clinical trials to learn more and develop better treatment and prevention methods. Visit our website to find an expert near you.