Acinetobacter etiology respiratory tract infections associated with mechanical ventilation: what impacts on the prognosis? A retrospective cohort study

Abstract

Introduction: Acinetobacter species treatment often represents a challenge. The main objective of this study is identify predictors of ICU mortality in patients submitted to mechanical ventilation (MV).

Materials and methods: Retrospective cohort study. Patients with MV > 48 h who developed a respiratory tract positive culture for Acinetobacter were included, and distinguished among colonized, ventilator-associated pneumonia (VAP) or ventilator-associated tracheobronchitis (VAT) patients. Primary outcome was ICU mortality.

Results: 153 patients were in MV and presented positive culture for Acinetobacter calcoaceticus-baumanii complex, 70 of them with VAP, 59 with VAT and 24 patients were colonized. The factors related to ICU mortality were VAP (OR 2.2, 95% CI 1.1-4.5) and shock at the time of diagnosis (OR 4.8, 95% CI 1.8-2.3). In multivariate analysis, only SOFA score at the time of diagnosis (OR 1.06, 95% CI 1.03-1.09) was related with ICU mortality. A paired-matched analysis was performed to assess effect of dual therapy on outcomes, and no effect was found in terms of clinical cure, ICU or hospital mortality or duration of antimicrobial therapy.

Conclusions: Previous comorbidities and degree of associated organic injury seem to be more important factors in the prognosis than double antibiotic therapy in patients with Acinetobacter-related respiratory infection.

Keywords: Acinetobacter; Hospital-associated pneumonia; Intensive care unit; Polymixin; Ventilator-associated pneumonia; Ventilator-associated tracheobronchitis.