Clinical features and prognosis of severe legionnaires' disease requiring intensive care unit admission: a multicentric retrospective cohort study.

Introduction: Legionella is the second cause of community-acquired pneumonia in Intensive Care Unit (ICU) patients. The aim of this study was to describe the epidemiology and outcome in patients with Legionella pneumonia (LP) in French ICUs.

Methods: A multi-center, retrospective, observational study in 12 French ICUs was performed between January 2014 and December 2019.

Results: LP was diagnosed in 162 patients during the study period. Invasive mechanical ventilation was required in 95 patients (58%), 73 (45%) of whom had acute respiratory distress syndrome (ARDS). Most of these patients were treated with a combination of antibiotics (128, patients; 79%). The most common combination consisted in a fluoroquinolone and a macrolide (118 patients). Median length of stay in an ICU was 11 [5; 11] days. At 28 days, 19 (12%) out of the 162 patients had not survived. In multivariate analyses, age (Incidence risk Ratio: IRR, 1.07; 95% CI, 1.01; 1.14) and a high Sequential Organ Failure Assessment (SOFA) score in the first 48 h (IRR, 1.47; 95% CI, 1.09; 2) were significantly associated with mortality.

Conclusion: In this French multicentric cohort, the LP prognosis in ICUs was apparently more favorable than in the literature, possibly because of the timely and improved LP management in ICUs.