Cat with UTI and kitten food

Good Morning:

We just got a new kitten and have a 5 year old cat with UTi and he has been eating the kitten food, is this safe and will it cause him any harm?

Depends in part on the kitten food. Is the food dry? Wet?
Brand name, etc.
Thanks.
PS: what did your vet recommend, food and other wise?

Thank you for replying, the kitten food is dry Iams Kitten food and the vet recommended Special UTI food for our older cat, but trying to keep him out of the food is very difficult, and I have noticed he is spitting up, do you know if kitten food is bad for a cat with UTI?

I believe it is the dry food--not so much whether it is marketed for kittens or adult cats--that is bad. For that reason, I think the dry food for kittens is bad. But from a purely nutritional standpoint, kitten food generally contains more calories than all-stage cat food.
The kitten food may not agree with your older cat from a digestive standpoint.
How old is the kitten?

Thank you again, the kitten is 6 weeks old, been to the vet for deworming and flea control, had two ear infections that we are giving him medicine for, tested negative for leukemia, and I'm just praying that it's just the food the older cat was eating that isn't agreeing with him. I am immediately going to change to canned, and feed them separately. I would hate for something to happen to our older cat, he's my prince.

Good move, switching to canned. Hydration is key to preventing UTIs. Many times a kitty that has had a UTI can simply be switched to canned, maybe with a little extra water added and go on problem free. (There are kitties, though, that don't do well unless they get prescription food.)

If you can test the urine with urine pH strips then you can have some feedback about the diet and the resulting urine pH. You want the urine readings to be around 6.5. Urine should be from a mid-stream sample, and readings can widely fluctuate throughout the day, so you need to get several samples. pH strips can be obtained from the aquarium section at the pet store or ordered from Amazon or eBay.