The bacteremic illness in the mother presents with a nonspecific
illness (flulike or gastrointestinal symptoms) and may progress
to amnionitis, preterm labor, or septic abortion in 3 to 7 days.6 Perinatal
listeriosis results in neonatal death or stillbirth in 22% of
the cases. Neonatal listeriosis has an early and a late onset presentation.
Neonates with early onset disease usually present at 1 to 2 days
of age, are born prematurely, and typically exhibit a septiclike
picture, although respiratory distress, pneumonia, and, rarely,
meningitis and granulomatosis infantisepticum are described. The
latter is manifested by diffuse granulomas in the liver, skin, and
placenta as well as other organs. Late onset disease typically presents
at 2 weeks of age, most commonly as meningitis. The case fatality
rate in neonates is 20% to 30%.4 Population-based
studies show that 88% of listeriosis in children younger
than 5 years occurs before 1 year of age, half of which presents
on the first day of life.7In 2006, 58 of 884 cases
reported in the United States were in children younger than 5 years, whereas
the majority of cases occurred in the elderly.8 After
the neonatal period, invasive listeriosis most commonly presents
as bacteremia without a source or as meningitis (30–55% of
cases) leading to neurologic sequelae in 30%. Other forms
of central nervous system infection include meningoencephalitis,
cerebritis, brainstem or spinal cord abscesses, and brainstem involvement
(rhombencephalitis).