Listeria Monocytogenes Infection (Listeriosis) Clinical Presentation

Updated: Aug 10, 2022
  • Author: Karen B Weinstein, MD, FACP; Chief Editor: Michael Stuart Bronze, MD  more...
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L monocytogenes infection may be a self-limited gastrointestinal tract illness or a more severe CNS infection, bacteremia, or a localized infection such as monoarticular septic arthritis.



Examination depends on the organ system involved.

Listeriosis in Pregnancy

Listeria may proliferate in the placenta and cause infection due to impaired cell-mediated immunity during pregnancy.

CNS infection is very rare during pregnancy, although it is observed frequently in other compromised hosts.

Fever, myalgias, arthralgias, back pain, and headache are classic symptoms of bacteremia. Symptoms may mimic those of a flulike illness. The infection may be mild and self-limited.

Listeriosis during pregnancy usually occurs during the third trimester, when cell-mediated immunity is at its lowest.

Preterm labor and/or delivery is common. Abortion, stillbirth, and intrauterine infection are possible.

Neonatal infection (granulomatosis infantisepticum)

Two forms are described. [8]

Early-onset sepsis, with Listeria acquired in utero via transplacental transmission, results in premature birth. Listeria can be isolated in the placenta, blood, meconium, nose, ears, and throat, among other sites, and manifests as abscesses and/or granulomas.

Late-onset meningitis is acquired through vaginal transmission, although it also has been reported with cesarean deliveries.

CNS infection

Listeria has a predilection for the brain parenchyma, especially the brain stem, and the meninges.

Mental status changes are common.

Seizures, both focal and generalized, occur in at least 25% of patients.

Cranial nerve deficits may be present.

Strokelike syndromes with hemiplegia may occur.

Nuchal rigidity is less common.

Movement disorders may include tremor, myoclonus, and ataxia.

Patients may present with encephalitis, especially of the brainstem. [9]

Meningitis is possible.

Ventriculitis, particularly of the fourth ventricle, may develop.

Cervical myelitis has been reported. [10]

Brain abscess occurs in 10% of CNS infections, often located in the thalamus, pons, and medulla. This uncommon complication is associated with high mortality. [11]

Febrile gastroenteritis

L monocytogenes can produce food-borne diarrheal disease, which is typically noninvasive.

The median incubation period is 1-2 days, with diarrhea lasting anywhere from 1-3 days.

The prevalence of diarrheal illness is high in individuals exposed to inocula of Listeria.

Patients present with fever, myalgias, and diarrhea and recover with supportive care.



Most infections are due to food-borne transmission.

A substantial minority of infections are transmitted by other modes. Transmission can occur transplacentally or via an infected birth canal. Isolated incidences of cross-infection in neonatal nurseries have been reported.

Nosocomial infection, while rare, has been reported.