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Listeriosis Infection

Listeriosis is a potentially serious disease caused by Listeria monocytogenes bacteria. This infection is uncommon, but certain children and adults have an increased chance of getting this illness, including pregnant women and their fetuses, as well as newborns and children with weakened immune systems. Pregnant women can spread the organism across the placenta and infect their unborn babies.

If a woman becomes infected with L monocytogenes early in her pregnancy, perhaps by eating contaminated food, she may have a high risk of a miscarriage. Late in pregnancy, the infection can cause stillbirth or, at times, serious illness or death in the newborn shortly after delivery. Although healthy children sometimes contract listeriosis, it rarely causes serious illness.

L monocytogenes is found in the environment. A person can get sick from these bacteria by eating contaminated foods such as soft cheeses (eg, feta, Brie, Camembert), unpasteurized milk, prepared meats (eg, hot dogs, deli meat, pâté), undercooked poultry, and unwashed raw vegetables.

Signs and Symptoms

When listeriosis occurs in an infant, the signs and symptoms may include

  • Listlessness
  • Vomiting
  • Loss of appetite
  • Jaundice (yellowing of the skin and eyes)
  • Skin rash
  • Breathing difficulties

Many childhood cases of listeriosis lead to meningitis. In older children and adults, listeriosis sometimes causes diarrhea.

How Is the Diagnosis Made?

Cultures are performed on blood, urine, and cerebrospinal fluid. If your pediatrician suspects that your newborn may have listeriosis, the placenta or amniotic fluid can be tested for the infectious organism.


Your pediatrician will prescribe antibacterials to treat L monocytogenes infections. For initial therapy, the doctor may recommend treating your baby intravenously with ampicillin plus an additional medication called an aminoglycoside (usually gentamicin). As your baby begins to get better, ampicillin alone can be given.

What Is the Prognosis?

When a fetus becomes infected with L monocytogenes, the prognosis is poor. The death rate is as high as 50%. The risk of death is also high when a newborn develops the infection.


To protect your child from listeriosis caused by food-borne organisms, you should follow procedures such as

  • Thoroughly cook raw food from animal sources.
  • Do not give your child unpasteurized dairy products.
  • Wash raw vegetables.
  • Store ready-to-eat foods at 40°F or lower.
  • Keep uncooked meats separate from vegetables.
  • Wash your hands, as well as knives and cutting boards, after they’ve touched uncooked foods.

When listeriosis is diagnosed in a pregnant woman, treatment of her infection can prevent the spread of infection to her newborn. Pregnant women can lower their risk of developing listeriosis by following these steps

  • Avoid soft cheeses.
  • Thoroughly cook leftover foods and ready-to-eat foods such as hot dogs until they are steaming hot.
  • Stay away from foods from delis such as prepared salads, meats, or cheeses, or heat these foods until steaming before eating.
  • Avoid unpasteurized or raw milk.
Last Updated
Immunizations & Infectious Diseases: An Informed Parent's Guide (Copyright © 2006 American Academy of Pediatrics)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
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