Effect of aerosolized colistin on multidrug-resistant Pseudomonas aeruginosa in bronchial secretions of patients without cystic fibrosis.

We performed a limited microbiological study to examine the effect of aerosolized colistin (1 million international units every 8 hours) on the colonization of the respiratory tract with Pseudomonas aeruginosa of five intubated, mechanically ventilated patients in the Intensive Care Unit (ICU). No adverse or side effects of the administered aerosolized colistin were reported. The microbial counts of Pseudomonas aeruginosa prior to the use of aerosolized colistin, as well as during the second, fourth, sixth, and eighth day after the use of the drug were measured. The results of this preliminary study suggest that aerosolized colistin was effective in reducing quickly the microbial counts and eliminating microbial growth of Pseudomonas aeruginosa by the sixth day of use in all studied patients.