Aspergillus in the lower respiratory tract of immunocompetent critically ill patients

Abstract

Objectives: To shed light on the meaning of Aspergillus-positive lower-respiratory-tract samples in non immunocompromized critically ill patients.

Methods: Multicentre matched case-control (1:5) study. We used prospectively collected data to identify risk factors for Aspergillus-positive specimens, as well as outcomes in Aspergillus-positive patients.

Results: 66 cases (5 with definite invasive pulmonary aspergillosis (IPA), 18 with probable IPA, and 43 colonisations) were matched to 330 controls. In the multivariate conditional logistic model, independent risk factors for at least one Aspergillus-positive respiratory-tract specimen were worse SAPSII at admission [OR, 1.10; 95%CI, 1.00-1.21], ARDS [OR, 2.64; 95%CI, 1.29-5.40]; long-term steroid therapy [OR, 4.77; 95%CI, 1.49-15.23]; steroid therapy started in the ICU [OR, 11.03; 95%CI, 4.40-27.67]; and bacterial infection [OR, 2.73; 95%CI, 1.37-5.42]. The risk of death, compared to the controls, was not higher in the cases overall [HR, 0.66; 95%CI, 0.41-1.08; p = 0.1] or in the subgroups with definite IPA [HR, 1.60; 95%CI, 0.43-5.94; p = 0.48], probable IPA [HR, 0.84; 95%CI, 0.28-2.50; p = 0.76], or colonisation [HR, 0.58; 95%CI, 0.33-1.02; p = 0.06]. In cases who received antifungal therapy, mortality was not lower than in untreated cases [HR, 0.67; 95%CI, 0.36-1.24; p = 0.20].

Conclusions: In critically ill immunocompetent patients, risk factors for presence of Aspergillus in lower respiratory tract specimens are steroid therapy (either chronic or initiated in the ICU), ARDS, and high severity of the acute illness. Prospective studies are warranted to further examine these risk factors and to investigate immune functions as well as the impact of antifungal therapy on patient outcomes.

Keywords: ARDS; Aspergillus; Bacterial infection; Immunocompromized; Mechanical ventilation.