Outcomes of adults with cystic fibrosis infected with antibiotic-resistant Pseudomonas aeruginosa.

BACKGROUND Although Pseudomonas aeruginosa is the most common bacterial infection in adults with cystic fibrosis and frequently develops resistance to multiple classes of antibiotics, it has not been determined whether patients with multiple antibiotic-resistant Pseudomonas aeruginosa have worse clinical outcomes than patients with more susceptible strains. OBJECTIVES This study assessed the impact of multiply-resistant P. aeruginosa on lung function, hospitalizations, antibiotic use, lung transplantation and survival in adults with cystic fibrosis. METHODS In a cohort study at a university-based adult cystic fibrosis program, 75 consecutive adult cystic fibrosis patients who had P. aeruginosa isolated from sputum cultures were studied over a 4-year period. Outcomes included decline in FEV1, clinic visits, hospitalizations, courses and days of intravenous antibiotics, and lung transplantation. Multiple linear and Poisson regression for repeated measures were used to assess the outcomes. RESULTS In comparison to patients with susceptible strains, patients with resistant P. aeruginosa had more severe baseline lung disease, more rapid decline in FEV1 (160 ml/year, p = 0.003) and were significantly more likely to undergo lung transplantation (17.6 vs. 0%, p = 0.005). CONCLUSIONS Infection with multiple-antibiotic-resistant P. aeruginosa is associated with accelerated progression of cystic fibrosis, and has important implications for infection control strategies, antibiotic use and lung transplantation.