Abstract
Listeria (L.) monocytogenes is a gram-positive, non-sporulating, facultatively anaerobic bacillus transmitted to humans through ingestion of contaminated foods. Listeriosis represents the third most common cause of death from foodborne illness, with a mortality rate of 20-30%, especially for patients affected by an invasive disease, which typically affects immunocompromised patients, pregnant women, the elderly, and neonates. It causes several clinical syndromes, of which meningitis, meningoencephalitis, and sepsis are the most challenging to deal with. Here, five cases of L. monocytogenes meningitis/meningoencephalitis affecting two previously healthy immunocompetent and three immunocompromised adult patients treated with ampicillin plus gentamicin are reported. In addition, all the patients described in this report received a low dose of intravenous dexamethasone; four of them made a full recovery. Additionally, a literature search was performed to better explain the appropriate clinical and therapeutic management approaches for these patients, highlighting the value of dexamethasone administration as part of the therapy.