i'm sorry but i have to disagree with you lot here. It really depends on the cat and the reason the cat is getting the UTI's. some get it from inflamation of the urethrea from an infection. some get it from malformed urethrea. some get it from struvite crystals. none of these really matter if you cat is eating wet or dry in fact there are wet and dry diets for urinary problems! Royal Canin make a brilliant new formula for urinary problems called High Dilution. I've seen fantastic results from it. One lil guy we thought we were going to have to amputate his penis off but he's fine now.

here are some articles you can have a look at that might give you a better look at things.
Reducing Struvite & Calcium Oxalate in the Urine of Cats

feline urinary tract disease in cats


also here is a cool new thing you can use in your litter to give you a heads up on your lil ones infection so you can get treatment sooner!
Nullodor Health indicator cat litter with colour coded early detection system.