Competetive microbial exclusion as treatment against complicated lower urinary tract infections

OBJECTIVE: Deliberate colonization of the lower urinary tract has been proposed as treatment against recurrent urinary tract infection - UTI. The bacteria chosen has to be able to colonize the urinary tract for longer periods without causing symptoms, and should be able to prevent manifest superinfections. MATERIALS: Sixteen patients (9 women and 7 males), all having a history of recurrent symptomatic UTI, were included in the study. The patients could be divided in four groups: (a) 5 males with neurogenic bladder disorder, due to suprasacral spinal cord injuries, (b) 3 patients, 1 female and 2 males, with ileocystoplasty, (c) 4 females with peripheral lesions, that caused post-voiding residual urine, and (d) 4 healthy women without any known dysfunction of the lower urinary tract. All patients, except one, was on clean intermittent catherization in the groups (a) and (b). The strain used for colonization, E. coli 83972, was isolated from a young female with asymptomatic bacteriuria,who had carried it for three years. It lacked expressed adherence factors and did not belong to the uropathogenic O:K:H serotypes. RESULTS: In 6 of the patiens we had successfull long time colonizations (5 months -2,5 years). The deliberate colonization had a high success rate in patients with neurogenic bladder disorder with high bladder capacity, residual urine and low detrusor pressure. All male patients, and 2 of the 4 females, with these characteristics were successfully colonized. In the patients with normal urinary tract function we had no successfull colonization. The colonizations were symptomless and prevented or competed out superinfections, demonstrated with repeated urine cultures. Only one supennfedting agent, Klebsiella pneumonia, in one patient at several times, became manifest All other detected superinfections were transient. CONCLUSIONS: Deliberate colonization of the lower urinary tract with E. coli 83972 may be a therapeutic alternative in selected patients with recurrent UTI. Further studies of host immune response, and of bacterial properties deciding percistence in the urinary tract, are necessery.