Study design (if review, criteria of inclusion for studies)
Microbiology results from two multicenter, double-blind, placebo-controlled trials
Participants
CF patients involved in two multicenter, double-blind, placebo-controlled trials of inhaled tobramycin in cystic fibrosis
Interventions
inhaled tobramycin
Outcome measures
longitudinal changes in sputum microbial flora, antibiotic susceptibility, and selection of P. aeruginosa isolates with decreased tobramycin susceptibility were measured. Clinical response was examined to determine whether current susceptibility standards are applicable to aerosolized administration.
Main results
Treatment with inhaled tobramycin did not increase isolation of Burkholderia cepacia, Stenotrophomonas maltophilia, or Alcaligenes xylosoxidans; however, isolation of Candida albicans and Aspergillus species did increase. Although P. aeruginosa tobramycin susceptibility decreased in the tobramycin group compared with that in the placebo group, there was no evidence of selection for the most resistant isolates to become most prevalent. The definition of resistance for parenteral administration does not apply to inhaled tobramycin: too few patients had P. aeruginosa with a tobramycin MIC >/=16 microgram/mL to define a new break point on the basis of clinical response.