RESUMEN
Listeria monocytogenes is a facultative anaerobic, gram-positive bacillus. Listeria is commonly found in processed and prepared foods and listeriosis is associated with high morbidity and mortality. This bacterium is an important cause of severe infection in neonates and pregnant women. Pregnant women are at high risk for listeriosis, but symptoms are non-specific and diagnosis is difficult. Neonatal Listeriosis is generally a severe and fatal disease. There are two forms of the disease in the neonate, early- and late-onset, suggesting different modes of transmission. Generally, early detection and empirical treatment of listeriosis help to improve survival and prognosis. We explained two cases of L. monocytogenes sepsis with culture-proven in preterm and late preterm newborns from asymptomatic mothers. These neonates had fulminant clinical course even if standard antibiotics treatments were administrated.