Antibiotic Prophylaxis at Urinary Catheter Removal Prevents Urinary Tract Infections. A Prospective Randomized Trial

Abstract

Urinary tract infections are common after removal of a urinary catheter and antibiotic prophylaxis is used to prevent them, although there is no supporting evidence that it is beneficial. One previous randomized placebo-controlled trial reported that antibiotic prophylaxis did not significantly reduce the rate of urinary tract infections following catheter removal but the number of patients included was small. This randomized controlled study assessed the effect of antibiotic prophylaxis at urinary catheter removal on the rate of subsequent urinary tract infections. The subjects in the final analysis, 205 patients undergoing elective abdominal surgery, were randomized to receive at catheter removal either 3 doses of trimethoprim-sulfamethoxazole (n = 103) or no prophylaxis (n = 102). Patients with known allergy to trimethoprim-sulfamethoxazole were given ciprofloxacin. Urinary cultures were obtained the day before and 3 days after catheter removal, and pathogenic bacteria were identified using Center of Disease Control definitions. The urinary catheters were left in place for 6.5 to 7 days in the 2 groups (P = 0.68). An independent study-blind urologist assessed subjective symptoms 4 ± 2 days after removal of the urinary catheter. The primary study end point was the occurrence of a urinary tract infection following catheter removal. Significantly fewer urinary tract infections (4.9%, 5/103) occurred in patients with antibiotic prophylaxis compared to those without prophylaxis (21.6%, 22/102) (P < 0.001). The absolute risk reduction for the presence of a urinary tract infection in the prophylaxis group was 16.7%, with a 95% confidence interval (CI) of 7.8% to 22.1%. The relative risk reduction was 77.5% (95% CI: 45.7%–91.9%), and the number needed to treat was 6 (95% CI: 4.5–12.8). There was also less significant bacteriuria 3 days after catheter removal in the antibiotic prophylaxis group (16.5%, 17/103) compared with the no prophylaxis group (41.2%, 42/102) (P < 0.001). The data suggest to the investigators that antibiotic prophylaxis at urinary catheter removal may reduce the rate of urinary tract infections. These findings are not consistent with those of a previous study showing no benefit of antibiotic prophylaxis for prevention of urinary tract infections after catheter removal.