USE OF AEROSOLIZED COLISTIN SODIUM IN CYSTIC-FIBROSIS PATIENTS AWAITING LUNG TRANSPLANTATION

Background. In patients with cystic fibrosis (CF) who are awaiting lun g transplant, prolonged exposure to systemic antibiotics has frequentl y led to airway colonization with resistant isolates of Pseudomonas. T his resistance limits the arsenal of effective antimicrobials availabl e for infections after the initiation of immunosuppression and has bee n considered a theoretical deterrent to lung transplantation. Methods. Twenty CF transplant candidates with ''pan-resistant'' Pseudomonas re ceived maintenance antibiotic therapy with aerosolized colistin sodium (75 mg b.i.d.), and intravenous antibiotics were eliminated. Ten othe r CF candidates did not use colistin sodium. Sputum cultures and antib iotic sensitivities were followed every 3-6 weeks. Results. All 20 can didates (100%) who used aerosolized colistin sodium became colonized w ith sensitive isolates of Pseudomonas in an average of 45.1 +/- 20.2 d ays. 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 14 4.6 +/- 48.0 days in candidates who did not use colistin sodium and wa s significantly longer than in the candidates who used colistin sodium (P=0.007). The occurrence of redeveloping sensitive isolates of Pseud omonas was significantly greater in the candidates who used colistin s odium (P<0.05). Of the candidates who used colistin sodium, six have b een 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 sodi um may be a useful therapy to promote emergence of sensitive microbes in CF candidates with pan-resistant isolates of Pseudomonas.