Listeriosis - A review of eighty-four cases

Objective: To review the epidemiology, risk factors for acquisition, clinical features and outcomes of Listeria monocytogenes infection in Sydney. Design: A retrospective study over the period 1983-1992 at four university teaching hospitals in Sydney. Cases were identified from microbiology laboratory records of the isolation of L. monocytogenes from sterile sites. Results: Eighty-four cases were reviewed, with 72 patients (86%) having a predisposing underlying condition, including 13 perinatal patients (15%). Septicaemia (56%) and central nervous system disease (41%) were the major clinical presentations. Nineteen patients (23%) had hospital-associated infection. A mortality of 21% (18 patients) was directly attributable to L. monocytogenes infection, with another 10% (nine patients) dying of their underlying disease during admission. The 84 cases represented 80% of all L. monocytogenes cases occurring in Sydney during the study period. Conclusions: Listeriosis is predominantly a disease of the elderly or of immunosuppressed individuals, pregnant women and neonates. The presentation and outcome in these groups are similar to those reported in other Western countries. A significant feature of this study was the number of cases occurring in already hospitalised patients, suggesting that L. monocytogenes may be an important hospital-associated pathogen in immunocompromised patients.