Listeriosis (Listeria monocytogenes Infection)

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Quick GuideBacterial Infections 101: Types, Symptoms, and Treatments

Bacterial Infections 101: Types, Symptoms, and Treatments

How does a person get listeriosis?

The majority of people who get listeriosis have consumed Listeria-contaminated foods. Because the bacteria are often found in both soil and water, cultivated foods like vegetables can easily become contaminated, especially from fertilizer or animal waste. Listeria has been found in many types of raw food (even seafood) but especially in meats, vegetables, and cheeses. It has even been found in processed foods because of contamination during or after processing. After the contaminated food or fluid has been ingested, it may take up to three weeks for the organisms to cause symptoms.

The fetus may become infected after the mother ingests the organisms; the bacteria apparently reach the fetus via the bloodstream. Newborn infants can acquire the bacteria during a cesarean procedure or be exposed to them while traversing the vagina.

What are the complications of listeriosis?

The major complications of listeriosis include

  • blood infection (septicemia/bacteremia),
  • meningitis and/or encephalitis,
  • brain abscesses,
  • seizures,
  • miscarriage,
  • premature birth,
  • neonatal sepsis (potentially fatal),
  • stillbirth, and
  • death.

Is it possible to prevent listeriosis?

Yes, listeriosis can be prevented. The CDC recommends the following food safety measures:

General recommendations:

  • Thoroughly cook raw food from animal sources, such as beef, pork, or poultry.
  • Wash raw vegetables thoroughly (scrub with a clean produce brush in uncontaminated running water) before eating.
  • Keep uncooked meats separate from vegetables and from cooked foods and ready-to-eat foods.
  • Avoid unpasteurized (raw) milk or foods made from unpasteurized milk.
  • Wash hands, knives, and cutting boards after handling uncooked foods.
  • Consume perishable and ready-to-eat foods as soon as possible.

Here are food safety recommendations for people at high risk, such as pregnant women and people with weakened immune systems, in addition to the recommendations listed above:

  • Do not eat hot dogs, luncheon meats, or deli meats, unless they are reheated until steaming hot.
  • Avoid getting fluid from hot-dog packages on other foods, utensils, and food preparation surfaces, and wash hands after handling hot dogs, luncheon meats, and deli meats.
  • Do not eat refrigerated pâtés or meat spreads. Canned or shelf-stable pâtés and meat spreads may be eaten.
  • Do not eat refrigerated smoked seafood, unless it is contained in a cooked dish, such as a casserole. Refrigerated smoked seafood, such as salmon, trout, whitefish, cod, tuna or mackerel, is most often labeled as "nova-style," "lox," "kippered," "smoked," or "jerky." The fish is found in the refrigerator section or sold at deli counters of grocery stores and delicatessens. Canned or shelf-stable smoked seafood may be eaten.
  • Avoid cross-contaminating other foods, utensils, and food-preparation surfaces with fluid from hot-dog packages, and wash hands after handling hot dogs.
  • Do not eat soft cheeses such as feta, Brie, and Camembert, blue-veined cheeses, or Mexican-style cheeses such as queso blanco, queso fresco, and Panela, unless they have labels that clearly state they are made from pasteurized milk. Cheeses that may be eaten include hard cheeses, semi-soft cheeses such as mozzarella, pasteurized processed cheeses such as slices and spreads, cream cheese, and cottage cheese.
  • Do not drink raw (unpasteurized) milk or eat foods that contain unpasteurized milk.

There is no commercially available vaccine to protect against infection by Listeria.

Medically Reviewed by a Doctor on 6/6/2017

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