Severe listeriosis in intensive care units: insights from a retrospective multicentric study

Listeriosis is a rare but severe foodborne infection, particularly affecting immunocompromised individuals and older adults. Severe cases may lead to neurolisteriosis and sepsis, necessitating intensive care unit (ICU) admission. This study aims to analyze the demographic characteristics, clinical presentation, microbiological findings, treatments, and outcomes of critically ill patients with Listeria infections in the ICU.

A retrospective multicenter study was conducted across 23 French hospitals over a 10-year period, including ICU patients with culture-confirmed Listeria monocytogenes infections. Data on demographics, comorbidities, ICU admission characteristics, biological and microbiological parameters, treatments, and outcomes were collected. The primary outcome was ICU mortality. A multivariable logistic regression model was used to identify factors associated with mortality in patients with neurological manifestations.

A total of 110 patients were included, with a median age of 68 years; 61% were male, and 71% were immunocompromised. Neurological involvement was present in most cases. Invasive mechanical ventilation was required in 58% of patients, and vasopressor support in 44%. ICU and in-hospital mortality rates were 25% and 32%, respectively. Among patients with neurolisteriosis, each 1-point decrease in Glasgow Coma Scale score at admission was associated with increased mortality (OR, 1.22; 95% CI 1.05-1.45; p = 0.009), as were higher cerebrospinal fluid (CSF) protein levels (OR, 1.56; 95% CI 1.15-2.41; p = 0.028). Steroid use was not significantly associated with reduced mortality (OR, 0.30; 95% CI 0.07-1.05; p = 0.076).

Listeriosis requiring ICU admission is associated with high morbidity and mortality, particularly in older and immunocompromised patients. The severity of these infections is reflected by the frequent need for organ support. Further research is needed to clarify the potential role of steroids in neurolisteriosis.