The only listeriae that cause human disease are L. monocytogenes and the rare species L. ivanovii. The designation L. monocytogenes results from the observation that infections of rodents, which are much more susceptible than humans, are accompanied by a monocytosis.
Listeria monocytogenes is nonspore-forming, noncapsulated bacilli, facultative intracellular, aero-anaerobic Gram positive bacterium able to invade, survive, and replicate in phagocytic cells and nonphagocytic cells, commonly found in soil, water, plants, decaying vegetation, and so on.
Listeriae are classic opportunists. In immunocompetent persons, an infection will either be clinically silent or present the picture of a mild flu. In immunocompromised patients, the disease manifests as a primary sepsis and/or meningoencephalitis. More rarely, listeriae cause endocarditis. Listeriosis during pregnancy may result in spontaneous abortion or connatal listeriosis (granulomatosis infantiseptica).
Human infection with L. monocytogenes can lead to abortion (in case of pregnancy) and meningitis in its severe form. This bacterium has been known to be associated with raw milk, not adequately pasteurized fluid milk, other dairy products, including cheeses (particularly soft-ripened varieties) and ice cream. This is mainly because of its ability to grow at temperatures as low as 3 oC permits its multiplication in refrigerated dairy products. However, this bacterium can be sufficiently killed by the usual pasteurization procedure.
Penicillins (amoxicillin) and cotrimoxazole, sometimes in combination with aminoglycosides, are used in therapy. Listeriosis is a rare infection characterized by sporadic occurrence. Occasional gastrointestinal epidemics due to contaminated food may result from the coincidence of unfortunate circumstances.
Listeria monocytogenes is nonspore-forming, noncapsulated bacilli, facultative intracellular, aero-anaerobic Gram positive bacterium able to invade, survive, and replicate in phagocytic cells and nonphagocytic cells, commonly found in soil, water, plants, decaying vegetation, and so on.
Listeriae are classic opportunists. In immunocompetent persons, an infection will either be clinically silent or present the picture of a mild flu. In immunocompromised patients, the disease manifests as a primary sepsis and/or meningoencephalitis. More rarely, listeriae cause endocarditis. Listeriosis during pregnancy may result in spontaneous abortion or connatal listeriosis (granulomatosis infantiseptica).
Human infection with L. monocytogenes can lead to abortion (in case of pregnancy) and meningitis in its severe form. This bacterium has been known to be associated with raw milk, not adequately pasteurized fluid milk, other dairy products, including cheeses (particularly soft-ripened varieties) and ice cream. This is mainly because of its ability to grow at temperatures as low as 3 oC permits its multiplication in refrigerated dairy products. However, this bacterium can be sufficiently killed by the usual pasteurization procedure.
Penicillins (amoxicillin) and cotrimoxazole, sometimes in combination with aminoglycosides, are used in therapy. Listeriosis is a rare infection characterized by sporadic occurrence. Occasional gastrointestinal epidemics due to contaminated food may result from the coincidence of unfortunate circumstances.
References:
- Kayser F, et al. 2005. Color Atlas of Medical Microbiology. Stuttgart: Thieme Medical Publisher.
- Schaechter Moselio. 2009. Encyclopedia of Microbiology 3rd Edition. New York: Academic Press.