Exploratory study of the prevalence and clinical significance of tobramycin-mediated biofilm induction in Pseudomonas aeruginosa isolates from cystic fibrosis patients.

Exposure to aminoglycoside antibiotics induces biofilm formation by a laboratory strain of the cystic fibrosis (CF) pathogen Pseudomonas aeruginosa. Here, we detected this effect among about half of the clinical isolates from CF patients in a cross-sectional collection, suggesting that biofilm induction may represent a common mechanism of inducible aminoglycoside resistance in CF infections. This induction always occurred at the same tobramycin concentration regardless of MIC, suggesting that the mechanisms of killing and induction may be separable.