Comparative evaluation of fleroxacin, ampicillin, trimethoprimsulfamethoxazole, and gentamicin as treatments of catheter-associated urinary tract infection in a rabbit model.

Fleroxacin, ampicillin, trimethoprim-sulfamethoxazole, and gentamicin were comparatively evaluated for effectiveness in treating experimentally induced catheter-associated urinary tract infection and bacteriuria in a rabbit model with a closed drainage system. Fleroxacin, ampicillin and gentamicin effectively eliminated a lactose-negative, streptomycin-resistant uropathogenic strain of Escherichia coli (WE6933) from bag urine and catheter port urine, while trimethoprim-sulfamethoxazole only marginally reduced urine bacterial counts when compared to rabbits that received no antibiotic therapy. Fleroxacin eliminated E. coli from the catheter surfaces and from tissues adjacent to the catheter. Ampicillin or gentamicin therapy also eliminated biofilm bacteria from the catheter surfaces, but did not eliminate th residual bacteria from tissue adjacent to the septic catheters despite achieving urine levels of antibiotics substantially higher than minimum bactericidal concentrations for this pathogen. Trimethoprim-sulfamethoxazole was ineffective in eliminating E. coli from the catheter surfaces and the adjacent tissues. The ability of fleroxacin to effectively eliminate biofilm bacteria from catheter surfaces and tissues adjacent to such medical devices in the urinary tract may prove useful in the treatment of catheter-associated urinary tract infection and bacteriuria in mammals and humans.