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 common resistant 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 Gram-negative 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) = 20·2, 95% confidence interval (CI): 5·5-73·6], Klebsiella pneumoniae (OR = 8·0, 95% CI: 1·9-33·6), and Pseudomonas aeruginosa (OR = 27, 95%: CI 2·7-273). Bronchial acquisition with resistant K. pneumoniae also was associated with chronic liver disease (OR = 3·9, 95% CI: 1·0-15·3), treatment with aminoglycosides (OR = 4·9, 95% CI: 1·4-18·2), tigecycline (OR = 4·9, 95% CI: 1·4-18·2), and linezolid (OR = 3·9, 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 Gram-negative microorganisms in the bronchial tree of newly intubated patients. Oropharynx colonization with the same pathogens and specific antibiotics use were independent risk factors.

Suspicion of respiratory tract infection with multidrug-resistant Enterobacteriaceae: epidemiology and risk factors from a Paediatric Intensive Care Unit

“…The OR of 4.56 (95% CI 1.69–12.30) for antibiotic exposure for ≥ 7 days indicates that after antibiotic therapy of 7 days or more, the risk of infection with MDR Enterobacteriaceae increases 4.56 times for every additional day of treatment. Our finding is consistent with numerous papers that have demonstrated antibiotic exposure as a strong risk factor for infection with MDR organisms [ 6 , 18 , 44 ]. Furthermore, this study investigated another important issue: namely, at which particular time an antibiotic might select MDR organisms in ventilated PICU patients.…”

“…MDR Enterobacteriaceae have become a particular concern for mechanically ventilated patients [ 4 ]. Placement of an endotracheal tube is followed rapidly by tracheal colonization with potentially pathogenic microorganisms from the oropharyngeal flora, including MDR organisms [ 5 , 6 ]. Colonization of the lower respiratory tract by endogenous flora or opportunistic pathogens provides the major route to acquiring ventilator-associated pneumonia (VAP) [ 7 ].…”

A plasmid locus associated with Klebsiella clinical infections encodes a microbiome-dependent gut fitness factor

“…Our previous work demonstrated a role for ter during Kp infection [10], therefore indicating that ter is important in the infectious process. Given that prior gut colonization often precedes disease [11][12][13]66], our finding that the ter operon is necessary for gut fitness in a microbiome-dependent manner corroborates our previous studies and explains why the ter operon is dispensable in murine models of pneumonia [10] and bacteremia but strongly associated with human infection in these sites. The importance of the ter operon is validated by the demonstration this operon is genetically independent, rather than a marker of the Kp hypervirulence plasmid.…”

Risk factors for multidrug‐resistant Gram‐negative bacteria infection in intensive care units: A meta‐analysis

“…Changes in diet, physiology, and medication treatment post‐operatively in hospitalized patients may have been responsible for making surgery a risk factor for development of MDR‐GNB infection. For postoperative patients, the physiological stress of the problem responsible for their inpatient stay, and the increased exposure to immunosuppressive agents, may have reduced their immunity and increased their risk of infection (Papakonstantinou et al, ).…”