[Invasive listeriosis - a rare and often severe infectious disease].

We describe the case of an immunocompromised patient in whom a severe infection with meningoencephalitis was detected. Listeria monocytogenes was the pathogen. Invasive listeriosis is a rare infectious disease that is notifiable in Switzerland and can be lethal. The most common route of contamination for the ubiquitous bacteria is the consumption of foods such as dairy products, raw vegetables or meat. Antibiotic treatment can lead to a complete cure.