Prevention of catheter-associated bacteriuria: clinical trial of methods to block three known pathways of infection.

The simultaneous use of methods to block all three known pathways of bacterial entry into the bladders of catheterized patients has been suggested because of the limited effectiveness of individual methods that block single pathways. We conducted a randomized controlled trial to assess the prevention of bacteriuria in patients, using a three-way system that included a hydrophilic polymer-coated and preconnected sealed catheter system, daily catheter care, and disinfection of the outflow tube of the drainage bag with povidone-iodine (i.e., methods to block bacterial entry at the urethral insertion site, at the catheter drainage tube junction, and at the outflow tube). Among treated patients, 14 (4.7%) of 300 acquired bacteriuria as compared with 15 (4.9%) of 306 who did not receive the protocol treatments. Only 3 of 29 episodes of bacteriuria occurred in patients whose meatal cultures did not contain gram-negative bacilli or enterococci; thus migration of bacteria in the periurethral mucous sheath appeared to be the most common pathway by which bacteria gained entry into the bladder in this study. Catheter care and disinfection of the drainage bag outflow tube as used in this study remain unproven methods of preventing catheter-associated bacteriuria. Preconnected catheters with junction seals were used in both treated and untreated patients and, on the basis of previous studies, appear to be effective in reducing junction disconnections and bacteriuria. Therefore we conclude that the use of several simultaneous measures to prevent catheter-associated urinary infections is no more effective than the use of preconnected catheters with junction seals alone and is clearly more expensive.