Effectiveness of inhaled tobramycin in eradicating Pseudomonas aeruginosa in children with cystic fibrosis

Background: Inhaled tobramycin therapy has been shown to be efficacious in clinical trials for the eradication of initial Pseudomonas aeruginosa infection in children with cystic fibrosis (CF). However, the effectiveness of different regimens in eradicating P. aeruginosa and preventing the development of chronic infection in actual clinical settings has yet to be determined. Methods: This was an observational study of children (<18 years of age) with CF with incident P. aeruginosa infection from 2005-2012 based on data collected from the Toronto CF Database and medical charts. Patients who received inhaled tobramycin (80 mg/2 ml twice daily for 365 days) were compared to those who received tobramycin inhalation solution (TIS) (300 mg/5 ml twice daily for 28 days) with respect to eradication and development of chronic infection. We also examined the risk factors for recurrence of infection. Results: During the study period, 65 patients were identified with incident P. aeruginosa, of which 7 (11%) failed eradication therapy. Eradication failure was similar between the two treatment groups. A total of 4 patients (6%) developed chronic P. aeruginosa infection in the 12 months following the end of therapy with no differences between treatment groups. Female gender, older age, pancreatic insufficiency, lower lung function and worse nutritional status were identified as risk factors for recurrence of P. aeruginosa infection. Conclusions: Both regimens of inhaled tobramycin have similar effectiveness in eradicating P. aeruginosa and preventing chronic P. aeruginosa infection in CF patients in clinical practice. Further work is needed, however, to identify patient characteristics and bacterial factors that play a role in eradication failure, in order to develop more effective antimicrobial rescue treatment strategies. (C) 2013 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.