Listeria (Listeriosis)

Definition

Image of Medscape PowerPoint Slide Listeria: Food Poisoning's Rare but Deadly Germ
February 27, 2012
Dr. Benjamin Silk presents key information on listeriosis in the aftermath of the large 2011 outbreak.

What is Listeriosis?

Listeriosis, a serious infection usually caused by eating food contaminated with the bacterium Listeria monocytogenes, is an important public health problem in the United States. The disease primarily affects older adults, pregnant women, newborns, and adults with weakened immune systems. However, rarely, persons without these risk factors can also be affected. The risk may be reduced by following a few simple recommendations.

What are the Symptoms of Listeriosis?

A person with listeriosis usually has fever and muscle aches, sometimes preceded by diarrhea or other gastrointestinal symptoms. Almost everyone who is diagnosed with listeriosis has "invasive" infection, in which the bacteria spread beyond the gastrointestinal tract. The symptoms vary with the infected person:

Pregnant women: Pregnant women typically experience only a mild, flu-like illness. However, infections during pregnancy can lead to miscarriage, stillbirth, premature delivery, or life-threatening infection of the newborn.
Persons other than pregnant women: Symptoms, in addition to fever and muscle aches, can include headache, stiff neck, confusion, loss of balance, and convulsions.

Listeriosis can present in different ways depending on the type of infection. Manifestations of listeriosis are host-dependent. In older adults and persons with immunocompromising conditions, septicemia and meningitis are the most common clinical presentations. Pregnant women may experience a mild, flu-like illness followed by fetal loss or bacteremia and meningitis in their newborns. Immunocompetent persons may experience acute febrile gastroenteritis or no symptoms.