Prevention of urinary tract infections.

Potential candidates for measures designed to prevent urinary tract infections include (1) women (or girls) with frequent exogenous reinfections; (2) pregnant women; (3) hospitalized patients with short-term indwelling catheters; (4) men with chronic bacterial prostatitis; (5) patients with neurogenic bladders being managed with either intermittent catheterization or chronic indwelling catheters; and (6) men undergoing urologic surgery. Patients in the first three categories represent the vast majority of men and women with preventable urinary tract infections. On the basis of our current understanding of the pathogenesis of urinary infections in women, potential preventive measures can be envisioned. To date, the most successful methods in susceptible women include continuous low-dose antimicrobial prophylaxis or postintercourse antibiotic prophylaxis. In controlled clinical trials, the efficacy of low-dose trimethoprim-sulfamethoxazole, trimethoprim, or nitrofurantoin has repeatedly been demonstrated, and the cost effectiveness of this approach has also been established. An alternative strategy, intermittent, self-administered, single-dose antimicrobial therapy, may be useful in selected circumstances. Screening of high-risk patients for asymptomatic infections has largely been abandoned except in pregnant women in whom this practice remains an important preventive measure. Exciting newer approaches to prevention based on studies clarifying the fimbrial structures mediating bacterial adherence to receptors on uroepithelial cells include the use of receptor analogs and immunoprophylaxis, but these approaches are not yet of demonstrated clinical efficacy.