There are not any foods available that I know of specifically for bladder infection. However, one can help prevent them by feeding a diet high in protein since that would increase the pH of the urine. A more acidic urine would make the urethra and bladder a more hostile environment for bacteria.
Also, cranberry pills. :smile: Cranberries contain a compound known as proanthocyanidins that act as an anti-adhesion factor and prevents bacteria from taking hold in the first place. Just get some cranberry pills that contain powdered cranberry extract from your local pharmacy, open them up into a small amount of water, mix, and then drizzle the mixture over your kibble to help prevent UTIs.
How large is your dog? Female, yes?
When your pooch does come down with a UTI, though, please bring them to a vet for appropriate medication.
Depending how often your dog contracts UTIs, it may be beneficial to feed a kibble with probiotics in it or to add some to their diet.