Listeria monocytogenes is the third most frequent cause of bacterial meningitis [2–5]. This gram-positive bacillus is principally spread by contaminated food, which was discovered after outbreaks of listeriosis in the 1980s [1, 6–9]. In the literature, meningitis due to L. It's most commonly caused by eating improperly processed deli meats and unpasteurized milk products. Healthy people rarely become ill from listeria infection, but the disease can be fatal to unborn babies, newborns and people with weakened immune systems. But most of the germs that can lead to bacterial meningitis aren't contagious. ... Not all bacteria that cause meningitis are spread from one person to another. You can also develop bacterial meningitis after eating certain foods containing the Listeria bacterium, such as: soft cheeses.