Listeriosis

Summary

Congenital listeriosis, caused by Listeria monocytogenes, is a rare foodborne infection transmitted transplacentally or during delivery, leading to miscarriage, stillbirth, preterm birth, or neonatal sepsis and meningitis; diagnosis is by blood/CSF culture, treatment is IV ampicillin with gentamicin, and prevention relies on food safety.

Overview

• Epidemiology

• Incidence: ~3 per 100,000 live births/year in the US.

• Pathogen

• Listeria monocytogenes.

• Transmission

• Maternal: ingestion of contaminated food (unpasteurized dairy, fish, meat, ready-to-eat vegetables).

• Fetal:

• Transplacental spread from infected mother.

• Direct exposure to infected vaginal secretions and/or blood during delivery.

• Clinical Features

• Maternal infection:

• Often asymptomatic or mild, flu-like illness (fever, chills, myalgia, diarrhea).

• Associated with spontaneous abortion, stillbirth, and preterm delivery.

• Neonatal infection:

• Early-onset (at birth):

• Granulomatosis infantiseptica.

• Disseminated abscesses in multiple organs.

• Respiratory distress, skin lesions, and possible early meningitis.

• Late-onset (5 days–3 weeks):

• Meningitis or meningoencephalitis.

• Diagnosis

• Culture of Listeria monocytogenes from blood or cerebrospinal fluid.

• CSF findings: pleocytosis.

• Treatment

• Intravenous ampicillin + gentamicin (mother and newborn).

• Prevention

• Avoid unpasteurized milk and soft cheeses.

• Avoid undercooked meats, contaminated water, and unsafe ready-to-eat foods.

• Nationally notifiable disease: mandatory reporting to health authorities.