Urinary tract infections are a result of interactions between the uropathogen and the host. Successful infection of the urinary tract is determined in part by the virulence factors of the bacteria such as type 1 fimbriae and/or P fimbriae, the inoculum size, and the inadequacy of host defense mechanisms. Detection of microorganisms through microbe-associated molecular patterns by Toll-like receptors is crucial to trigger protective innate immunity. A rapid cytokine response was observed when Escherichia coli bacteria infected the epithelial cells with production of interleukin-1ß (IL-1ß), IL-6, and IL-8. These factors play a role in determining the damage to the urinary tract.