Listeria monocytogenes meningitis is most common in which group?

• A. Ages 1 month - 50 years
• B. Neonates
• C. >50 years or alcoholics
• D. All age groups equally

Answer: (A)

Listeria meningitis targets people with weaker cell-mediated immunity, so the extremes of age and immune compromise are the main risk groups. Infants have immature T-cell responses, while older adults experience immunosenescence; pregnant women and other immunocompromised individuals are also at higher risk. Because of this, Listeria meningitis is most commonly seen in neonates and in people over about 50 years old, rather than being evenly distributed across ages.

Among the options, the classic high-risk group is neonates, with age over 50 also being a recognized high-risk category. The idea that it’s most common strictly within a broad 1 month to 50 year range doesn’t fit the established pattern of risk.