Abstract
The urinary tract is constantly exposed to microorganisms that inhabit the gastrointestinal tract, but generally the urinary tract resists infection by gut microorganisms. This resistance to infection is mainly ascribed to the versatility of the innate immune defences in the urinary tract, as the adaptive immune responses are limited particularly when only the lower urinary tract is infected. In recent years, as the strengths and weaknesses of the immune system of the urinary tract have emerged and as the virulence attributes of uropathogens are recognized, several potentially effective and unconventional strategies to contain or prevent urinary tract infections have emerged.