A single dose of aztreonam in the prevention of urinary tract infections in elderly catheterized patients.

We have compared the effects of aztreonam and placebo in the prevention of urinary tract infections (UTI) in elderly hospitalized patients who needed urethral catheterization. 162 patients (96 males, 66 females; age range 60-91 years) were randomly allocated to receive double-blind a single dose of aztreonam (2 g i.m. 80 patients) or placebo (4 ml lidocaine 2%, 82 patients) three hours before catheterization. All patients were followed-up for 7 days. Urine culture was performed before, at the first, third and seventh day of catheterization. At the end of follow-up 71/80 patients (88.7%) who received a single preventing dose of aztreonam had negative urine culture without clinical signs of UTI. On the contrary, in the group treated with placebo at the end of follow-up only 38/82 patients (46.3%) had negative urine without clinical signs of UTI. In conclusion, our data suggest that a single 2g i.m. dose of aztreonam is effective in preventing UTI in elderly patients needing indwelling urethral catheterization.