A gram-positive bacterial infection that affects neonates, pregnant women, adults over 45 to 50 years of age, and immunocompromised people.
Mainly a food-borne disease. Prevention consists of hand hygiene, cooking food well, and avoiding unwashed and leftover food.
Bacteremia, sepsis, meningitis, encephalitis, brain abscess, endocarditis, and gastroenteritis are the most common clinical manifestations.
Cultures from clinically sterile sites and serologic tests are the keys for laboratory diagnosis.
Ampicillin is the preferred drug for initial treatment for systemic (nongastroenteritis) manifestations. Gastroenteritis alone is usually self-limited.
Listeriosis is a food-borne infection caused by a motile, nonspore-forming, gram-positive bacillus. Its incidence is relatively low in the general population. 
Honorary Clinical Senior Lecturer
Consultant in Acute and General Medicine
PMK declares that he has no competing interests.
Infectious Diseases Division
Massachusetts General Hospital and Harvard Medical School
EM is an author of several references cited in this monograph. He has also received grant support from T2 Biosystems, Astellas pharma, and Boehringer Ingelheim. He is also a member of Astellas pharma.
Professor of Medicine and Community Health
JDR declares that he has no competing interests.
Infection and Immunity
Southern General Hospital
AL declares that he has no competing interests.
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