Listeria infections typically resolve without treatment, but antibiotics may be necessary to treat some cases.
Non-invasive Listeria infection is usually a self-limiting illness—which means that a majority of infected individuals will improve without the need for medical care. But for those patients with a high fever, a stool culture and antibiotic treatment may be justified (even for otherwise healthy individuals).
In a retrospective observational study conducted in Denmark between 1997 and 2012, the researchers found a statistically significant association between inadequate empiric therapy of L. monocytogenes bacteremia/meningitis and a higher 30-day mortality. They noted that this was likely related to the late identification of Listeria as the offending pathogen:
No primary focus of infection was found in the majority of patients, most probably because L. monocytogenes bacteraemia has few clinical characteristics except for fever, which may subside intermittently. Hence, empiric treatment often followed the local guidelines for treatment of sepsis with an unknown focus.
Indeed, more than half of the patients received inadequate empiric antibiotic treatment, and the therapy was not changed until L. monocytogenes was cultured from blood or CSF.
Invasive infections with Listeria can be treated with antibiotics. When infection occurs during pregnancy, antibiotics given promptly to the pregnant woman can often prevent infection of the fetus or newborn. Babies with listeriosis receive the same antibiotics as adults, although a combination of antibiotics is often used until physicians are certain of the diagnosis.
From Johns Hopkins’ ABX Guide for Listeria monocytogenes: