Purpose: The authors had for aim to describe the characteristics of listeriosis encephalitis patients enrolled in a national study.

Methods: Listeria monocytogenes was identified as the forth etiology of encephalitis, in a prospective study in France, in 2007. We analyzed 12 cases with confirmed listeriosis (seven with rhombencephalitis, five with encephalitis) and compared them with encephalitis of other etiologies and with listeriosis encephalitis, mandatorily notified during the same year.

Results: L. monocytogenes strains were genoserotyped as IVb (n=6), IIa (n=3), and IIb (n=3). Cerebrospinal fluid (CSF) median protein level was 2.5g/L and the median WBC counts was 367cells/mm(3). Among twelve patients, seven patients had ongoing comorbidities. The case fatality rate during hospitalization was 50%. Patients presenting with listeriosis enrolled in the study did not differ from those reported to the mandatory surveillance system according to their demographical characteristics and comorbidities. They were older, presented more frequently with cancer, or were more often under corticosteroid treatment than patients presenting with encephalitis due to other etiologies.

Conclusions: Neurolisteriosis has a poor prognosis, thus it should be considered early in patients presenting with encephalitis to improve its management.