Background Chronic bronchial infection with Pseudomonas aeruginosa in patients with non-cystic fibrosis (CF) bronchiectasis/chronic obstructive pulmonary disease (COPD) is related to worsening lung function and increased morbidity and mortality. Inhaled antibiotics represent an effective therapeutic approach for these diseases.

Purpose To evaluate the use of inhaled colistin in the treatment of chronic colonisation with Pseudomonas aeruginosa in patients with non-CF bronchiectasis/COPD.

Materials and Methods Retrospective study of patients with COPD/non-CF bronchiectasis colonised with Pseudomonas aeruginosa treated with inhaled colistin for at least three months from January 2008 to April 2012. Data collected: sex, age, diagnosis, duration of the treatment, disease-related hospitalizations pre and post-treatment, sputum cultures, clinical evolution.

Results 5 patients (3 with non-CF bronchiectasis and 2 with COPD) and 6 treatment episodes (1 patient received 2 courses of treatment) were included. Treatment duration was 27.6 months (range 4–48). Average cost per patient €13,896 (range €2,950–25,888). In 5 episodes, treatment was initiated after ≥4 consecutive sputum cultures positive for Pseudomonas resistant to tobramycin/ciprofloxacin. No difference in number of disease-related hospitalizations/month pre-and post-treatment (0.25 vs. 0.26). Sputum Pseudomonas eradication (3 consecutive negative sputum samples) was reported in 2 patients; treatment was continued, which was an unnecessary cost of €15,500 (22% of total costs). No resistance developed to colistin. In two episodes (one with eradication) clinical improvement occurred (reduction in cough and expectoration).

The number of hospitalizations/month was similar before and after treatment, and the microbiological response (negative results on sputum) and the clinical response (reducing cough and sputum purulence) was moderate (2 of 6 episodes).

Three patients died from their bronchial disease.

Conclusions In most episodes the initial prescription was correct (≥3 consecutive sputum cultures positive).

In patients whose Pseudomonas had been eradicated, treatment was continued, therefore sputum cultures should be monitored more frequently.

No effective treatment was observed.

No conflict of interest.