EFFECTS OF CIPROFLOXACIN, NORFLOXACIN, AND OFLOXACIN ON IN-VITRO ADHESION AND SURVIVAL OF PSEUDOMONAS-AERUGINOSA AK1 ON URINARY CATHETERS

Pretreatment of urinary silicone latex catheters in vitro with 0.1 and 0.5 mu g of ciprofloxacin per ml for 1, 24, and 48 h significantly re duced the adhesion and survival of the clinical isolate Pseudomonas ae ruginosa AK1. W spectroscopy and high-performance liquid chromatograph y confirmed the presence of ciprofloxacin adsorbed onto the catheters and showed that up to 56% of the drug Leached into the surrounding flu id within 24 h. Scanning electron microscopy demonstrated that the adh erent organisms were malformed and elongated after exposure to ciprofl oxacin. Transmission electron microscopy showed the presence of fimbri ae on the bacterial surfaces, but there was no conclusive evidence of changes in the fimbriae upon exposure to ciprofloxacin. It was found t hat a significant eradication of 24-h Pseudomonas biofilms could be ac hieved with ciprofloxacin as well as with ofloxacin and norfloxacin. P reincubation of catheters with 50- and 100-mu g/ml concentrations of c iprofloxacin resulted in up to a 99% reduction in the number of adhere nt bacteria in comparison with the reduction on control catheters. In addition, adherent biofilms were eradicated by 24 h of challenge with 50 and 100 mu g of ciprofloxacin per ml at pH 7.0 and 5.5. Results of these in vitro studies suggest that there could be a clinical role for fluoroquinolones in preventing and treating urinary tract infections associated with P. aeruginosa adherence to prosthetic devices.