Pilot trial of bacterial interference for preventing urinary tract infection.

To examine the safety and efficacy of bacterial interference in preventing symptomatic urinary tract infection (UTI). A prospective, nonrandomized, pilot clinical trial was conducted in patients with spinal cord injury who had neurogenic bladder and had frequent episodes of symptomatic UTI. The bladder of patients was inoculated with a nonpathogenic prototype of Escherichia coli 83972. The rate of symptomatic UTI in successfully colonized patients while colonized with E. coli 83972 was compared with (a) their own baseline prestudy rate and (b) the rate of symptomatic UTI in patients who were not successfully colonized. Of 44 inoculated patients, 30 (68%) became colonized with E. coli 83972 for 1 month or longer. Only two episodes of symptomatic UTI occurred in the group of 30 patients while colonized with E. coli 83972 (a total of 34 patient-years), and none was attributed to E. coli 83972. The group of 30 patients experienced a 63-fold reduction in the rate of symptomatic UTI while colonized with E. coli 83972 versus their baseline prestudy period (mean 0.06 versus 3.77 episodes of symptomatic UTI/patient-year, P <0.001). The rate of symptomatic UTI was also 33-fold lower in this group of 30 patients while colonized with E. coli 83972 than in the well-matched group of 14 patients who were not successfully colonized (mean 0.06 versus 1.80 episodes of symptomatic UTI/patient-year, P <0.001). The results of this pilot study indicate that bacterial interference using E. coli 83972 may be safe and effective in preventing UTI.