It appears to be your first post (1), so lets check something.
What are you feeding?
Dry food may leave a cat a bit dehydrated (they aren't as sensitive to thirst), which allows the bladder contents to become more concentrated. This can make the urine more irritating. If you switch to a low carb canned food, there will be more moisture going in (dilution) and less glucose going out (which may feed bacteria ,if it spills into the urine).
If you have a diabetic cat, and are giving insulin, you need to be testing the glucose so you can adjust for the change in carbohydrate level. It may drop the insulin requirements as much as units.
Also, unless a cystocentesis was done (urine drawn out with a needle), you don't know for sure that it is a bacterial infection. Cats can get a condition called interstitial cystitis which basically means the bladder is very irritated and triggers frequent urination and there may even be blood in it. This can be due to food allergies sometimes. It may (or may not) help to give glucosamine.
