Use of aerosolized colistin sodium in cystic fibrosis patients awaiting lung transplantation.

BACKGROUND In patients with cystic fibrosis (CF) who are awaiting lung transplant, prolonged exposure to systemic antibiotics has frequently led to airway colonization with resistant isolates of Pseudomonas. This resistance limits the arsenal of effective antimicrobials available for infections after the initiation of immunosuppression and has been considered a theoretical deterrent to lung transplantation. METHODS Twenty CF transplant candidates with "pan-resistant" Pseudomonas received maintenance antibiotic therapy with aerosolized colistin sodium (75 mg b.i.d.), and intravenous antibiotics were eliminated. Ten other CF candidates did not use colistin sodium. Sputum cultures and antibiotic sensitivities were followed every 3-6 weeks. RESULTS All 20 candidates (100%) who used aerosolized colistin sodium became colonized with sensitive isolates of Pseudomonas in an average of 45.1+/-20.2 days. In contrast, only 3 of 10 CF transplant candidates (30%) who did not use colistin sodium later became colonized with sensitive isolates. The mean time to spontaneous emergence of sensitive organisms was 144.6+/-48.0 days in candidates who did not use colistin sodium and was significantly longer than in the candidates who used colistin sodium (P=0.007). The occurrence of redeveloping sensitive isolates of Pseudomonas was significantly greater in the candidates who used colistin sodium (P<0.05). Of the candidates who used colistin sodium, six have been transplanted at our institution. In five of these six recipients (83.3%) bacterial cultures taken from the explanted lungs continued to demonstrate sensitive organisms. CONCLUSION Aerosolized colistin sodium may be a useful therapy to promote emergence of sensitive microbes in CF candidates with pan-resistant isolates of Pseudomonas.