Listeriosis
Listeriosis is invasive infection with the foodborne gram-positive rod Listeria monocytogenes, ranging from self-limited gastroenteritis in healthy hosts to bacteremia, meningitis, or rhombencephalitis in pregnant, neonatal, elderly, or immunocompromised patients, confirmed by culture of a sterile site, and treated with ampicillin, since the organism is intrinsically resistant to all cephalosporins.
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What this article covers
- Overview
Listeriosis is infection with Listeria monocytogenes, a gram-positive, facultative intracellular rod acquired through contaminated food, that ranges from mild self-limited gastroenteritis in healthy…
- Epidemiology
Acquired through ingestion of unpasteurized dairy products, soft cheeses, deli meats, hot dogs, smoked seafood, and contaminated produce (for example cantaloupe), with periodic multistate outbreaks traced to specific food recalls.
- Risk factors
Pregnancy, which markedly increases susceptibility to invasive infection and carries risk to the fetus regardless of how mild maternal symptoms appear.
- Pathophysiology
Listeria monocytogenes is a facultative intracellular, catalase-positive gram-positive rod that is ingested with contaminated food and crosses the intestinal epithelium, after which it disseminates hematogenously and lymphatically.
- Clinical features
Presentation depends heavily on host risk factors.
- Differential diagnosis
Streptococcus pneumoniae or Neisseria meningitidis meningitis: more acute onset with classic meningismus and a more often positive cerebrospinal fluid (CSF) Gram stain, unlike the subacute…
- Diagnosis
Invasive listeriosis is confirmed by isolating Listeria monocytogenes in culture from a normally sterile site: blood, cerebrospinal fluid, amniotic fluid, placenta, or neonatal specimens; culture is…
- Management
First, for any patient with suspected bacterial meningitis who is over age 50, pregnant, immunocompromised, or a neonate, add ampicillin to the standard empiric regimen (vancomycin plus a…
- Complications
Fetal loss, stillbirth, or preterm labor from maternal bacteremia and placental infection.
- Prognosis
Mortality from invasive listeriosis (bacteremia or meningitis) in high-risk hosts is substantial, roughly 20% to 30%, reflecting the vulnerability of the affected population as much as the organism's virulence.
- Prevention
Pregnant women and immunocompromised patients should avoid unpasteurized milk and cheeses (including soft cheeses such as queso fresco), avoid deli meats and hot dogs unless reheated to steaming hot…
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