EFFECTS OF CIPROFLOXACIN AND PROTAMINE SULFATE COMBINATIONS AGAINST CATHETER-ASSOCIATED PSEUDOMONAS-AERUGINOSA BIOFILMS

Infection is a common complication associated with the use of transcut aneous and implanted medical devices. These infections are generally d ifficult to treat and frequently require removal of the biomaterial be fore the infection can be completely eradicated, The presence of a bac terial biofilm recalcitrant to treatment often mediates these infectio ns, We studied the influence of a polycationic protein, protamine sulf ate, on the efficacy of the fluoroquinolone ciprofloxacin against a cl inical isolate of Pseudomonas aeruginosa. A P. aeruginosa biofilm was developed on 1-cm sections of red rubber catheter material and then tr eated with various combinations of protamine sulfate and ciprofloxacin , The present work demonstrated that ciprofloxacin in combination with protamine was more effective against biofilms than was ciprofloxacin alone, Protamine sulfate at 50 mu g/ml combined with antibiotic at 0.5 mu g/ml reduced the number of viable cells by an average of 98.97%, w hile protamine sulfate at 50 mu g/ml alone resulted in an average 107. 8% increase and antibiotic alone resulted in an average 58.6% reductio n after 24 h, Furthermore, protamine sulfate, in combination with cipr ofloxacin, inhibited P. aeruginosa in a dose-dependent fashion. It was further observed that treatment with the combination of protamine sul fate and ciprofloxacin had a more drastic effect on planktonic organis ms as compared with the P. aeruginosa biofilms; the MBC was reduced to <0.05 mu g/ml in the presence of 25 mu g of protamine sulfate per ml. These findings were substantiated by ultrastructure studies of treate d cells using scanning and transmission electron microscopy, The syner gism between ciprofloxacin and protamine sulfate significantly enhance d the efficacy of ciprofloxacin against planktonic and biofilm P. aeru ginosa.