Suggest Treatment For Chronic UTI S

I suffer from chronic UTI s. My bladder was washed out with antibiotics about 6 months by urologist. UTIs still recurring. Very quick onset of pain and blood in urine, so much that it comes out red. No stinging or burning. I take every precaution and have had no sexual activity for ten years. I am a 62 year old female with one child birth 34 years ago and a hysterectomy 22 years ago, including removal of ovaries. I have also developed an am unity to the antibiotics the doctor would prescribe. Now I need to take a stronger one that requires Australian government federal Heath dept approval. Are you able to suggest what could be causing this. Thank you.