Eradication of multidrug-resistant Acinetobacter baumannii from the respiratory tract with inhaled colistin methanesulfonate: a matched case-control study

Abstract

Repeated isolation of multidrug-resistant Acinetobacter baumannii (MDRAB) from respiratory secretions poses a great challenge for infection control. We conducted a retrospective case-control study to evaluate the efficacy and adverse effect of inhaled colistin methanesulfonate (CMS) in the eradication of MDRAB from the respiratory tract. Patients who were admitted to Taipei Veterans General Hospital between February 2009 and June 2010, had at least two sets of monomicrobial culture of MDRAB from respiratory secretions, and remained in hospital for at least 14 days after the first isolation of MDRAB (index day) were included. Patients who received intravenous CMS were excluded. Patients who received CMS inhalation for ≥ 3 days were selected as cases whereas the controls were matched for age and Acute Physiology and Chronic Health Evaluation II score. Thirty-nine cases and controls were identified. The duration of CMS inhalation was 10.9 ± 3.6 days. The use of inhaled CMS was the only independent factor associated with the eradication of MDRAB within 14 days after the index day (OR 266.33; 95% CI 11.26-6302.18, p <0.001), and shortened the duration of MDRAB recovery from the respiratory tract by 13.3 ± 1.45 days. The adverse effects were similar for both groups. The increase of colistin minimal inhibitory concentrations in the last isolate compared with the index isolate from the same patient did not differ between the two groups. In conclusion, our study demonstrated that inhaled CMS enhanced the eradication of MDRAB from the respiratory tract without significant clinical adverse effect or impact on colistin resistance.

Role of aerosolized colistin methanesulfonate therapy for extensively-drug-resistant Acinetobacter baumannii complex pneumonia and airway colonization

“…conducted in Taiwan, when aerosolized CMS was used in a mixed population (both XDRAB-infected and -colonized patients) for eradication of XDRMB from the respiratory tract, recognized benefits were the shortening of contact isolation duration and reduction of cost for isolation measures. 12 As XDRAB can colonize multiple body sites 3 and survive for a long time in the environment, 1,2 eradication of XDRAB from the respiratory tract may not be an effective hospital infection control measure. Further studies are needed to evaluate the impact of such a practice on hospital infection control.…”

“…5,11 Some hospitals in Taiwan have also employed aerosolized CMS for eradication of XDRAB as part of their infection control measures. 12 Despite the increasing use of aerosolized CMS for XDRAB pneumonia, its clinical benefit has not been well studied. Bacterial colonization of the airway is crucial for development of nosocomial pneumonia.…”

Clinical and Pathophysiological Overview of Acinetobacter Infections: a Century of Challenges

“…In contrast, nebulizing polymyxins has the potential to achieve very high concentrations in the lungs while minimizing systemic exposure and toxicity. Numerous investigators have described favorable outcomes of patients with nonbacteremic Acinetobacter pneumonia who were treated with nebulized polymyxins (252)(253)(254)(255)(256)(257)(258)(259)(260)(261). In one case-control study, use of inhaled colistin increased microbial eradication rate from the airways in ventilated patients compared to systemic therapy (257).…”

Comparison of the efficacy of colistin monotherapy and colistin combination therapies in the treatment of nosocomial pneumonia and ventilator-associated pneumonia caused by Acinetobacter baumannii

“…Eradication was con sidered as bacterial absence in two consecutive samples from respiratory tract secretions during or at the end of the treatment. [9] Respiratory tract specimens taken from the ICU patients were sent to the Infectious Diseases and Clinical Microbiology Laboratory of our hospital. Here, the samples were inoculated into blood agar and eosin methylene-blue lactose sucrose agar, and the antibiotic susceptibilities were studied in Mueller-Hinton agar medium using the Kirby-Bauer Disk Diffusion method in accordance with the standards of Clinical and Laboratory Standards Institute for microorganisms growing after 24 -48 hours.…”