Case‑specific epidemiological investigation: A patient infected with Listeria monocytogenes at a private hospital in Bangkok, February 2025

Abstract

Listeria monocytogenes is a Gram-positive bacterium that can cause listeriosis, an infection with an incubation period of 3–70 days. It is a severe illness, especially dangerous for vulnerable populations such as pregnant women, infants, the elderly, obese individuals, and those with weakened immune systems. This bacterium is commonly found in the environment and can survive in cold conditions, making it a frequent contaminant of refrigerated and processed foods. The aim of this study was to investigate a specific, confirmed case of Listeria monocytogenes infection in a patient with a history of consuming food from street vendors or in public areas—typically sold from stalls, carts, or food trucks. Data were collected on clinical symptoms, food consumption history, environmental exposure, and laboratory results. Although the exact source of infection could not be definitively identified, the investigation suggests that eating fresh street food sold from stalls, carts, or food trucks was a major risk factor. This investigation highlights the importance of establishing food traceability systems and enhancing food safety surveillance. It also proposes control and prevention strategies at the healthcare and community levels, includes international cooperation, and emphasizes the need for widespread communication to high-risk groups. These measures aim to prevent future outbreaks and strengthen public health security.