My puppy Benji, a male 4-month golden puppy, is having a 4th time UTI. I am sooo tired and frustrated. We've visited our vet several times. Everytime he was given a period of antibiotics. When he was on antibiotics, it looked it was solved. However, several days after the course was over, the UTI just went back. Every single time. Did additional urine culture after his antibiotics for his 2nd UTI and it came back clean. A few days later, he had the 3rd UTI. We've also done the ultrasound and there was nothing wrong and no stone was found. Now is the 4th UTI. What could go wrong? Also have been giving him daily cranberry supplement.