Listeriosis in 225 non-pregnant patients in 1992: clinical aspects and outcome in relation to predisposing conditions.

Clinical information was collected on 225 cases of Listeria monocytogenes (LM) infection not associated with pregnancy occurring in France in 1992. Infections affected primarily men (62%) and persons over 65 years of age. Of the cases found, 81% occurred in persons with some underlying condition: 34% involved patients with severe immunosuppression; 37% were on dialysis or had diabetes mellitus, alcoholism, hepatic failure or malignancies without immunosuppressive therapy; and 10% had other underlying conditions not clearly associated with immunosuppression. The clinical presentation of listeriosis depended on the predisposing factors: in previously healthy adults central nervous system infection was the most frequent clinical form (80%), whereas the group characterized by severe immunosuppression or other immunosuppressive conditions tended to develop bacteraemia (52%). The rate of hospital-associated cases (11%) was lower than that reported in other countries. Mortality directly related to LM infection was 24%. Predisposing disease was the major prognostic factor. No fatal outcome was observed in the group of adults < 65 years old without underlying conditions. In summary, although classification based on the degree of alteration of T-cell-mediated immunity enables determination of the role of predisposing conditions in cases of listeriosis outside of pregnancy, clinical aspects and outcome of listeriosis vary within these groups and depend on the severity of each underlying disease.