Risk factors for tracheobronchial acquisition of resistant gram-negative bacterial pathogens in mechanically ventilated ICU patients

Abstract

The aim of this study was to identify risk factors for tracheobronchial acquisition with the most commonresistant Gram-negative bacteria in the intensive care unit (ICU) during the first week after intubation and mechanical ventilation. Tracheobronchial and oropharyngeal cultures were obtained at admission, after 48 hours, and after 7 days of mechanical ventilation. Patient characteristics, interventions, and antibiotic usage were recorded. Among 71 eligible patients with two negative bronchial cultures for resistant Gramnegative bacteria (at admission and within 48 hours), 41 (58%) acquired bronchial resistant Gram-negative bacteria by day 7. Acquisition strongly correlated with presence of the same pathogens in the oropharynx: Acinetobacter baumannii [odds ratio (OR)520.2, 95% confidence interval (CI): 5.5–73.6], Klebsiella pneumoniae (OR58.0, 95% CI: 1.9–33.6), and Pseudomonas aeruginosa (OR527, 95%: CI 2.7–273). Bronchial acquisition with resistant K. pneumoniae also was associated with chronic liver disease (OR53.9, 95% CI: 1.0–15.3), treatment with aminoglycosides (OR54.9, 95% CI: 1.4–18.2), tigecycline (OR54.9, 95% CI: 1.4–18.2), and linezolid (OR53.9, 95% CI: 1.1–15.0). In multivariate analysis, treatment with tigecycline and chronic liver disease were independently associated with bronchial resistant K. pneumoniae acquisition. Our results show a high incidence of tracheobronchial acquisition with resistant Gramnegative microorganisms in the bronchial tree of newly intubated patients. Oropharynx colonization with the same pathogens and specific antibiotics use were independent risk factors. © 2015 Edizioni Scientifiche per l’Informazione su Farmaci e Terapia