Oral fluoroquinolone therapy results in drug adsorption on ureteral stentsand prevention of biofilm formation

The oral administration of ciprofloxacin (250mg bid) and ofloxacin (300mg b id) in 40 patients with ureteral stents, led to drug levels on all the devi ce surfaces that were higher than the minimum inhibitory concentration (MIC ) of Escherichia coli (0.004-0.015 mg/l). the most common uropathogen. The drug levels in the film were higher than the MIC of other common pathogens, namely Psuedomonas aeruginosa (0.25-1.0 mg/l), E,Enterococcus faecalis (0. 25-2.0 mg/l) and Staphylococcus aureus (0.12-0.5 mg/l) in a few cases (six, three and 14 cases out of 40, respectively). For both antibiotics, the con centrations were greater than the MIC of many uropathogens on the film surr ounding the devices (0.89) vs 0.31 mg/l respectively, (P = 0.05), and on th e devices themselves (0.22 vs. 0.12 mg/l. P=0.207). Adsorption of the antib iotics was higher to the film than to the stent (P < 0.0001). Ciprofloxacin concentration on the film surrounding the stents was significantly higher than that of ofloxacin (P = 0.05), while there was no statistical concentra tion difference between the two antibiotics adsorbed onto the actual device s (P = 0.207). No bacteria were found in patients' urine and no biofilms we re detected. This is the first report of an oral antibiotic being adsorbed onto medical devices. it potentially provides a new approach of preventing infection, and avoids the need to pre-coat devices with agents whose use wi ll be restricted once bacteria develop resistance to them. If biomaterial p roperties can be enhanced to increase further the adsorptive concentration of drug, the risk of infections and recalcitrant biofilm formation could be significantly reduced in a highly susceptible patient population, <(c)> 20 01 Elsevier Science B.V. and International Society of Chemotherapy. All rig hts reserved.