In light of the current avocado recall, here’s the high yield information medical students should know!
Listeria monocytogenes is a gram positive, beta-hemolytic, rod-shaped bacteria that grows well in cold environments.
This pathogen is commonly ingested with consumption of contaminated dairy products, deli meats, and in the recent recall, avocados. In healthy individuals this bacteria may cause self-limited gastroenteritis and fever. Listeria monocytogenes is a concern for neonates, pregnant women, elderly, and immunosuppressed individuals. In these individuals, Listeria may cause meningitis, meningoencephalitis, or bacteremia. Concerns in pregnant women may also include amnionitis and granulomatosis infantiseptica.
Diagnosis of Listeria is commonly through CSF or blood culture, in the case of outbreaks special media can be used for stool culture. Characteristic of listeria is the tumbling motility seen with light microscopy. First-line treatment of listeriosis is usually ampicillin or penicillin G. CNS, neonatal, and immunocompromised infections are often treated with gentamicin for synergistic effects.