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Listeria monocytogenes

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Listeria monocytogenes, Listeriosis

  • See Also
  1. Acute Diarrhea
  2. Foodbourne Illness
  3. Gram Positive Rod
  4. Bacterial Meningitis
  • Pathophysiology
  1. Non-spore forming Gram Positive Rod (Diphtheroid similar to Corynebacterium)
  2. Facultative Anaerobe, and able to grow at cold Temperatures (4 to 10 C)
  3. Flagella which result in a tumbling-type of motility
  4. Listeriolysin O is a virulence factor produced by Listeria
    1. Activated in the acidic environment of Phagosomes (e.g. Macrophages)
    2. Results in cytolysis of Macrophages, resulting in release of Listeria monocytogenes
  5. Listeriolysin O allows for Listeria to survive within immune cells as a facultative Intracellular Organism
    1. Immunocompetent patients can destroy intracellular Listeria
    2. However, Immunocompromised patients are enable to fully eradicate intracellular Listeria
  6. References
    1. Gladwin, Trattler and Mahan (2014) Clinical Microbiology, Medmaster, Fl, p. 59-61
  • Causes
  • Sources
  1. See Foodbourne Illness
  2. Deli Meat
  3. Frozen Vegetables (2016 outbreak in U.S.)
  4. Unpasteurized milk (including derived soft cheese, cole slaw, butter)
    1. (2008) MMWR Morb Mortal Wkly Rep 57(40):1097-100 +PMID:18846031 [PubMed]
  • Risk Factors
  • Severe, invasive disease
  1. Elderly or Immunocompromised patients (e.g. Lymphoma, Corticosteroids, organ transplant, AIDS)
    1. Listeria is among the most common Meningitis causes in this cohort
  2. Pregnancy
    1. Typically, affects women in the third trimester, resulting in bacteremia and Sepsis
    2. Affects the fetus in nearly one quarter of cases resulting in neonatal death or premature birth
  3. Newborns
    1. Infection may be acquired via Vaginal Delivery in asymptomatic, colononized mothers
    2. Results in Neonatal Sepsis and Meningitis, most commonly presenting at 2 weeks of life
  • Symptoms
  1. Onset
    1. Gastrointestinal symptoms start within 9 to 48 hours
    2. Immunocompetent hosts typically have self-limited course
    3. Invasive disease onset delayed for 2 to 6 weeks
  2. Gastrointestinal infection
    1. Fever
    2. Diarrhea
    3. Nausea
    4. Myalgias
  3. Invasive infection (esp. Immunocompromised patients)
    1. Bacteremia
    2. Meningitis
    3. Endocarditis
  4. Pregnancy (presents with flu-like illness)
    1. Premature delivery
    2. Stillbirth
  • Labs
  1. Missed on Stool Culture
  • Management
  1. See Acute Diarrhea
  2. Antibiotics
    1. Not typically used (self-limited disease in normal hosts)
    2. Consider in severe, invasive cases or high risk patients (5 days Amoxicillin or Septra has been used)
  • Resources
  1. CDC Listeria
    1. http://www.cdc.gov/listeria/
  • References
  1. Ooi (2005) Clin Infect Dis 40(9): 1327-32 +PMID: 15825036 [PubMed]
  2. Switaj (2015) Am Fam Physician 92(5): 358-65 [PubMed]