If there's blood in the urine, she's going to need to be on antibiotics again even though I really hate saying it. Two years between infections really is pretty good - usually, when a cat developes a urinary tract infection, it seems to be a chronic thing that recurs every few months. You might try giving her ONE DROP of unsweetened cranberry juice every morning once you get this cleared up as that will help bring the urine's ph to the correct level and hopefully avoid the problem in the future. Adding canned food to her diet will also raise the moisture content in her gut and may also help prevent the problem down the road.
Please let me know if I can assist further.
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Lori McLaughlin
Your veterinarian should ALWAYS be consulted first and foremost when your pet's welfare is at stake.