Listeriosis (Listeria monocytogenes Infection)

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Medical Author:

Charles Patrick Davis, MD, PhD

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.

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Medical Editor:

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.

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Medical Editor:

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.

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• Listeriosis is a disease caused by a gram-positive bacterium named Listeria that can penetrate and replicate inside human cells.
• Most people who are infected have few or no symptoms; when symptoms are present, they usually consist of fever, muscle aches, nausea, or diarrhea. Some people may develop more severe symptoms such as meningitis, mental changes, brain abscesses, or death.
• Although most people have self-limited disease, people with risk factors such as an altered or depressed immune response (for example, pregnant females and their fetus or newborn, cancer patients, AIDS patients) are at higher risk for getting the disease and some are more likely to have more severe disease.
• Listeriosis is usually diagnosed by discovering that a person was associated with an outbreak of Listeria-contaminated food or fluid or identified as a person associated with the source of a known listeriosis outbreak. Definitive diagnosis is done when Listeria bacteria are isolated from the patient's blood, cerebrospinal fluid, or other body fluid.
• Most normal people spontaneously clear the infection and require no treatment. In contrast, people with risk factors should be treated quickly with IV antibiotics.
• People are exposed to Listeria bacteria if they ingest contaminated food or fluid. Foods that are not cooked or fluids that are not treated or pasteurized are frequently the sources of infection. Pregnant females can transmit Listeria organisms to their fetus or to their newborn.
• Cooking foods, treating or pasteurizing fluids, and avoiding food and fluids that may be contaminated with animal or human waste may prevent infection.
• The prognosis for most Listeria infections is excellent even if people have consumed contaminated foods or fluid; however, the prognosis rapidly declines in patients with risk factors if they are not quickly diagnosed and treated.
• U.S. government agencies are responsible for maintaining safe foods and fluids for the U.S. population and may enforce regulations to ensure contaminated products are reported, removed, recalled, and production and sales stopped until processing meets acceptable standards of safety.