Significant microbiological effect of inhaled tobramycin in young children with cystic fibrosis. Placebo-controlled, double-blind, randomized study of aerosolized tobramycin for early treatment of Pseudomonas aeruginosa colonization in cystic fibrosis. Prevention of chronic Pseudomonas aeruginosa colonisation in cystic fibrosis by early treatment.
We conducted a double-blind, placebo-controlled, multicenter, randomized trial to test the hypothesis that 300 mg of tobramycin solution for inhalation administered twice daily for 28 days would be safe and result in a profound decrease in Pseudomonas aeruginosa (Pa) density from the lower airway of young children with cystic fibrosis. Ninety-eight subjects were to be randomized; however, the trial was stopped early because of evidence of a significant microbiological treatment effect. Twenty-one children under age 6 years were randomized (8 active; 13 placebo) and underwent bronchoalveolar lavage at baseline and on Day 28. There was a significant difference between treatment groups in the reduction in Pa density; no Pa was detected on Day 28 in 8 of 8 active group patients compared with 1 of 13 placebo group patients. We observed no differences between treatment groups for clinical indices, markers of inflammation, or incidence of adverse events. No abnormalities in serum creatinine or audiometry and no episodes of significant bronchospasm were observed in association with active treatment. We conclude that 28 days of tobramycin solution for inhalation of 300 mg twice daily is safe and effective for significant reduction of lower airway Pa density in young children with cystic fibrosis. In chronic Pseudomonas aeruginosa pulmonary infection of patients with cystic fibrosis (CF), antibiotic therapy generally fails to eradicate the bacterial pathogen. The mucoid bacterial phenotype, high sputum production by the host, and low airway levels of antibiotics seem to be responsible for the observed decrease in antibiotic efficacy. We hypothesized that early antibiotic treatment by inhalation in CF patients may be able to prevent or at least delay airway infection. In a prospective placebo-controlled, double-blind, randomized multicenter study, 22 CF patients received either 80 mg b.i.d. of aerosolized tobramycin or placebo for a period of 12 months shortly after the onset of P. aeruginosa pulmonary colonization. Two patients in the tobramycin and six patients in the placebo group stopped inhalation before the 12 month treatment period. Using life table analysis, the time to conversion from a P. aeruginosa-positive to a P. aeruginosa-negative respiratory culture was significantly shorter in the tobramycin-treated group than in the placebo group (P < 0.05, log rank test). Lung function parameters and markers of inflammation did not change in either group during treatment. The results of this study suggest that early tobramycin inhalation may prevent and/or delay P. aeruginosa pulmonary infection in CF patients. To assess whether chronic pulmonary colonisation with Pseudomonas aeruginosa in cystic fibrosis is preventable, 26 patients who had never received anti-pseudomonas chemotherapy were randomly allocated to groups receiving either no anti-pseudomonas chemotherapy or oral ciprofloxacin and aerosol inhalations of colistin twice daily for 3 weeks, whenever Ps aeruginosa was isolated from routine sputum cultures. During the 27 months of the trial, infection with Ps aeruginosa became chronic in significantly fewer treated than untreated subjects (2 [14%] vs 7 [58%]; p less than 0.05) and there were significantly fewer Ps aeruginosa isolates in routine sputum cultures in the treated group (49/214 [23%] vs 64/158 [41%]; p = 0.0006). Thus, chronic colonisation with Ps aeruginosa can be prevented in cystic fibrosis by early institution of anti-pseudomonas chemotherapy.
We found that nebulised antibiotics, alone or in combination with oral antibiotics, were better than no treatment for early infection with Pseudomonas aeruginosa. Eradication may be sustained in the short term. Overall, there is insufficient evidence from this review to state which antibiotic strategy should be used for the eradication of early Pseudomonas aeruginosa infection in CF.