Effect of Bladder Catheterization On Bacterial Interference With Asymptomatic Escherichia coli Strain 83972 in an Experimental Porcine Model of Urinary Tract Infection

BACKGROUND: Urinary tract infection (UTI) is a common disease with a significant risk of relapse. Deliberate bladder colonization with asymptomatic Escherichia coli is being explored as a potential strategy to fend off invading uropathogens, thereby mitigating the risk of symptomatic UTI. Currently, one major obstacle is the low success rates for achieving persistent bladder colonization with asymptomatic bacteria and experimental challenge studies are lacking. Here, we assessed the influence of an indwelling bladder catheter on the ability of asymptomatic E. coli to colonize the bladder and to assess the protective efficacy of such colonization against experimental UTI with uropathogenic E. coli.

METHODS: Pigs with or without indwelling bladder catheters were experimentally inoculated with the asymptomatic E. coli strain 83972 and subsequently challenged by inoculation with a uropathogenic E. coli isolate, UTI89. The animals were monitored with regular urine and blood samples and bladders and kidneys were harvested at termination.

RESULTS: All pigs with indwelling catheters were colonized by E. coli 83972 in response to inoculation, compared to pigs without catheters in which only 1 of 8 animals were colonized. When removing the catheter, E. coli 83972 were spontaneously cleared. Colonization with E. coli 83972 prevented experimental infection in 50% of animals, whereas all control animals became infected.

CONCLUSIONS: The presence of indwelling bladder catheters strongly facilitates the colonization of E. coli 83972, indicating that individuals with catheters may be particularly suited for receiving this treatment. The research supports prophylactic colonization with E. coli 83972 as a potential strategy to reduce the risk of UTIs.