Survival of Stenotrophomonas maltophilia following exposure to concentrations of tobramycin used in aerosolized therapy for cystic fibrosis patients

The use of aerosolized tobramycin is an important component in the manageme nt of patients with cystic fibrosis, particularly those with chronic Pseudo monas aeruginosa infection. Clinicians have been concerned that long-term t herapy with aerosolized tobramycin may increase the risk of colonization wi th multi-resistant bacteria, including Strenotrophomonas maltophilia. The a bility of five strains (three clinical, two environmental) of S. maltophili a to survive exposure to 16 000 mug/mL tobramycin, a concentration commonly found inside the atomization chamber of nebulizers used to deliver aerosol ized therapy, was studied. Under a variety of different growth conditions, all five strains were able to survive exposure to 16 000 mug/mL of tobramyc in. Post-exposure recovery was enhanced at 20 degreesC and 30 degreesC in c omparison with 37 degreesC under all test conditions. The importance of the se findings in relation to the epidemiology of S. maltophilia in patients w ith cystic fibrosis is discussed. (C) 2001 Elsevier Science B.V. and Intern ational Society of Chemotherapy. All rights reserved.