Clinical Manifestations and Risk Factors Influencing Eradication of Extensive Multidrug-resistant Acinetobacter baumannii from the Respiratory Tract

Purpose: Extensive multidrug-resistant Acinetobacter baumannii (XDRAB) has increasingly emerged as one of the most difficult bacteria to treat in the healthcare setting. In this study, we intended to evaluate the factors affecting eradicating XDRAB from the respiratory tract, clinical manifestations, and treatment outcomes. Methods: We retrospectively reviewed the medical records of patients who had XDRAB isolated from the respiratory tract in our medical center from January 1, 2012 to February 28, 2013. Results: In total, 87 patients were included in this study. Eradication was achieved in 69 patients (79.3%). The factors that negatively affect eradication of XDRAB by aerosolized colistin therapy for two weeks included: (1) receiving noninvasive mechanical ventilation; (2) being infected/colonized during residency in long-term care facilities; and (3) receiving combination therapy with intravenous tigecycline. The 30-day mortality in patients with versus without eradication was 26.1% versus 55.6%, respectively (. p<0.05), and the in-hospital mortality rate (40.6% vs. 66.7%, p<0.05), were significantly lower in the eradication group than the noneradication group. Steroid use was associated with significantly higher overall mortality (32% vs. 61%, p<0.05) in both high and low dose groups. Conclusion: XDRAB eradication from the respiratory tract is associated with improved clinical outcomes. Clinicians should be aware of the possible negative effect of combination therapy with aerosolized colistin and tigecycline for eradicating XDRAB.