Listeria monocytogenes bacteremia:: analysis of 110 episodes

BACKGROUND AND OBJECTIVE: Over the last years, we registered an increase in the number of listeriosis cases. The aim of this study was to analyze the co-morbidity, clinical presentation and prognosis of Listeria monocytogenes bacteremia episodes diagnosed over 15 years. PATIENTS AND METHOD: From January 1991 to April 2005, we prospectively recorded the medical records of 110 patients in whom L. monocytogenes was isolated from one or more blood cultures. In all patients, demographic, clinical presentation, antimicrobial treatment and outcome data were recorded. RESULTS: Twenty cases (18.2%) were recorded from 1991 to 1995; 27 (24.6%) from 1996 to 2000 and 63 (57.3%) from 2001 to April 2005 (p < 0.05). One hundred patients (90.9%) had one or more underlying diseases or immunosuppressive conditions, and 54 (49.9%) were under steroid therapy. In 63 patients, primary bacteremia developed, in 35 there was a central nervous system infection and 6 patients developed a spontaneous peritonitis (all patients with liver cirrhosis). Thirteen patients (11.8%) developed septic shock, and 18 (16.3%) died. The mortality rate of patients with meningitis who were treated empirically with a third generation cephalosporin was 50% (5 out of 10) whereas the mortality rate of those patients who received initially an antimicrobial agent active against L. monocytogenes was 12% (3 out of 25) (p = 0.05). CONCLUSIONS: The rate of systemic infection due to L. monocytogenes increased over the last years. Immunosuppressed patients should have a better knowledge of the guidelines needed to avoid eating potentially contaminated food. When empiric treatment is to be selected in immunosuppressed patients with unexplained fever and/or meningitis, a lack of activity against L. monocytogenes by cephalosporins should be considered.