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Contributors: Haya Raef MD, Susan Burgin MD, Paritosh Prasad MD
Other Resources UpToDate PubMed


Listeriosis is caused by infection with the gram-positive bacillus Listeria monocytogenes. The organisms infect farm and laboratory animals worldwide and are rarely directly transferred to humans by handling infected animals. Ingestion of contaminated milk, cheese, and poultry is the main source of human infection. Contaminated produce is rarely the cause, although there has been an increase in produce-related illnesses in the past few years.

Most adult infections appear to be subclinical, but clinical infections ranging from mild to severe have been reported. Most symptomatic adult infections occur in immunocompromised patients and in those at the extremes of age, but adult infections in farmers and veterinarians do occur. Listeriosis is associated with increased susceptibility among pregnant individuals, who account for 1 in 4 reported cases in the United States. Infections during pregnancy can lead to stillbirth.

Severe infection can be manifested with meningitis, gastrointestinal symptoms and signs, or a glandular fever-like illness. Hematogenous spread and widespread dissemination is rare.

Cutaneous involvement outside of the neonatal period is rare and usually occurs from direct inoculation of the skin in farmers or veterinarians who are exposed to animal products of conception.

Pediatric patient considerations:
As with adults, in children, infection and illness are more likely in the immunocompromised. Infection can occur by ingestion of contaminated or unpasteurized milk or ingestion of cheeses from unpasteurized milk.

The highest incidence of disease is in the neonatal period. See neonatal listeriosis for more information.


A32.9 – Listeriosis, unspecified

4241002 – Listeriosis

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

In pregnant patients:
Central nervous system (CNS) infection:
  • Sepsis from other types of bacteremia

Best Tests

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Management Pearls

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Drug Reaction Data

Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.

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Last Reviewed:02/22/2021
Last Updated:08/12/2021
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A medical illustration showing key findings of Listeriosis : Diarrhea, Rash, Contaminated food exposure, Malaise, Myalgia, Currently pregnant
Clinical image of Listeriosis - imageId=232590. Click to open in gallery.  caption: 'Numerous pustules with surrounding erythema on the forearm.'
Numerous pustules with surrounding erythema on the forearm.
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