Listeria monocytogenes
- Diagnosis
- Background
- Lab Tests
- References
- Related Topics
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
- CSF
- Amniotic fluid
- Maternal/fetal tissues
Differential Diagnosis
- Diarrhea
- Other agents of gastroenteritis (viral, bacterial, parasitic)
- Meningeal symptoms
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.
Epidemiology
- Prevalence – ~1,600 people/year in U.S. infected (CDC, 2016)
Organism
- Gram-positive facultative, intracellular rods
- Hardy organism – capable of growing at both 4ºC and 37ºC
- Organisms are motile by means of flagella at room temperature, but not at 37ºC (body temperature); can spread from cell to cell via actin polymerization
- L. monocytogenes is the only recognized human pathogen in Listeria species and has >14 serotypes
- Infection usually follows eating 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
- Corticosteroids
- Transplant drugs
- Cancer
- HIV/AIDS
- Chronic diseases
- Age >65 years
- Pregnancy
Clinical Presentation
- Initial symptoms – fever, muscle aches, nausea, diarrhea
- Localized infection
- Skin
- Intra-abdominal
- More serious symptoms may develop if infection spreads
- Systemic sepsis
- Central nervous system infection
- Manifestations in pregnancy
- Sepsis in mother and newborn
- Spontaneous or septic abortion
- Still birth
Cerebrospinal Fluid (CSF) Culture and Gram Stain 0060106
Method: Stain/Culture/Identification
Identify bacteria in CSF
Blood Culture 0060102
Method: Continuous Monitoring Blood Culture/Identification
Detect presence of bacteria in blood
Identify Listeria as agent of infection
Testing is limited to the University of Utah Health Sciences Center only
Body Fluid Culture and Gram Stain 0060108
Method: Stain/Culture/Identification
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
Anaerobe culture is NOT included with this order
Listeria Antibody, Serum by CF 0099529
Method: Semi-Quantitative Complement Fixation
Confirm Listeria as agent of infection (endocarditis, CNS)
Document past infection if culture was not performed or if patient received antibiotics that would make culture unreliable
Listeria Antibody, CSF by CF 2002086
Method: Semi-Quantitative Complement Fixation
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
General 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
Medical Reviewers
Last Update: September 2016
