Effects of sub-inhibitory concentrations of antibiotics on surface expression of ferripyochelin-binding protein in Pseudomonas aeruginosa.

Growth of Pseudomonas aeruginosa in medium containing sub-inhibitory concentrations of tobramycin, tetracycline or chloramphenicol repressed surface expression of the ferripyochelin binding protein (FBP). Ciprofloxacin did not repress FBP surface expression but increased the amount of detectable FBP. Sub-MICs of tetracycline, tobramycin and chloramphenicol also reduced ferripyochelin uptake by whole cells. An additional Mr = 19,000 protein was detected with monoclonal antibody in outer membranes of cultures grown in the presence of tetracycline and chloramphenicol. This protein is presumed to be a precursor form of FBP. No other major changes in LPS migration patterns or outer membrane protein profiles were observed in cultures grown in the presence of these antibiotics. These data suggest that exposure of P. aeruginosa to sublethal doses of tobramycin, tetracycline or chloramphenicol can alter the ability of these organisms to acquire iron.