Listeria monocytogenes is the causative agent of listeriosis and is transmitted through contaminated foods. Listeriosis is a virulent foodborne illness with 20-30% mortality, especially in immunocompromised individuals.
Tabs Content Clinical Overview Diagnosis
Indications for Testing
High level of suspicion coupled with symptoms in at-risk patients
Laboratory Testing
CDC – diagnosis and testing recommendations Rapid detection tests may be available (monoclonal antibodies or nucleic acid hybridization) but may only identify genus Listeria
Culture
Blood
Cerebrospinal fluid (CSF)
Amniotic fluid
Maternal/fetal tissues
Differential Diagnosis
Background
Epidemiology
Prevalence – ~1,600 people/year in U.S. (CDC, 2016)
Organism
Gram-positive facultative, intracellular rods
Hardy organism – capable of growing at both 4ºC and 37ºC
Motile by means of flagella at room temperature, but not at 37ºC (body temperature); can spread from cell to cell via actin polymerization
The only recognized human pathogen in Listeria species; has >14 serotypes
Infection usually follows consumption of contaminated food (listeria can grow and multiply in a refrigerated state)
Uncooked meats and vegetables
Unpasteurized milk and cheeses
Processed foods (eg, soft cheeses, processed meats, smoked seafood)
Risk Factors
Immunocompromised state as a result of
Chronic diseases
>65 years
Pregnancy
Clinical Presentation
Initial symptoms – fever, muscle aches, nausea, diarrhea
Localized infection
More serious symptoms (may develop if infection spreads)
Systemic sepsis
Central nervous system (CNS) infection
Manifestations in pregnancy
ARUP Lab Tests
Detect presence of bacteria in blood
Identify bacteria in normally sterile body fluids
Anaerobe culture is recommended for body fluids, tissue, and deep wound/surgical cultures; refer to anaerobe culture and gram stain
For CSF specimens, order CSF culture and gram stain
For blood specimens, order blood culture or blood culture, AFB and fungal
Anaerobe culture is NOT included with this order
Confirm Listeria as agent of infection (endocarditis, central nervous system [CNS])
Document past infection if culture was not performed or if patient received antibiotics that would make culture unreliable
Confirm Listeria as agent of infection (CNS)
Document past infection if culture was not performed or if patient received antibiotics that would make culture unreliable
References Allerberger F, Wagner M. Listeriosis: a resurgent foodborne infection. Clin Microbiol Infect. 2010; 16(1): 16-23. PubMed
Bortolussi R. Listeriosis: a primer. CMAJ. 2008; 179(8): 795-7. PubMed
Drevets DA, Bronze MS. Listeria monocytogenes: epidemiology, human disease, and mechanisms of brain invasion. FEMS Immunol Med Microbiol. 2008; 53(2): 151-65. PubMed
Gandhi M, Chikindas ML. Listeria: A foodborne pathogen that knows how to survive. Int J Food Microbiol. 2007; 113(1): 1-15. PubMed
Posfay-Barbe KM, Wald ER. Listeriosis. Semin Fetal Neonatal Med. 2009; 14(4): 228-33. PubMed
Ramaswamy V, Cresence VM, Rejitha JS, Lekshmi MU, Dharsana KS, Prasad SP, Vijila HM. Listeria--review of epidemiology and pathogenesis. J Microbiol Immunol Infect. 2007; 40(1): 4-13. PubMed
Related Topics Last Update: October 2019
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