Influencing factors of successful eradication of multidrug-resistant Acinetobacter baumannii in the respiratory tract with aerosolized colistin

Background: The increased prevalence of multidrug-resistant Acinetobacter baumannii (MDRAB) poses a worldwide treatment challenge. Although aerosolized colistin therapy for MDRAB pneumonia has attracted increasing interest, factors influencing successful eradication remain unclear. Methods: This retrospective study evaluated 135 consecutively admitted adult patients showing positive respiratory secretion cultures for MDRAB who underwent aerosolized colistin therapy between January 2007 and November 2011. Possible factors related to pneumonia and MDRAB eradication were collected for analysis. Results: Patients with successful MDRAB eradication on Day 14 had a shorter interval between the day the positive MDRAB sputum cultures were yielded and the day colistin inhalation treatment began (4.0 ± 2.5 vs. 7.3 ± 6.5; p = 0.002). Patients with a worsening chest X-ray on Day 7 of the colistin inhalation had a lower chance of 14-day MDRAB eradication [1/44 (2.3%) vs. 8/37 (21.6%); p = 0.006]. Patients with diabetes mellitus also had a lower chance of early MDRAB eradication [13/44 (29.5%) vs. 20/37 (54.1%); p = 0.025]. Conclusions: Early intervention using aerosolized colistin in patients with MDRAB pneumonia or colonization can achieve better eradication.