Hi, After going through your history, I can understand your concerns, since you have taken prolonged courses of antibiotic with no benefit. It is important to find out why your infection is persistent. 1. The culture report of E. coli would have included a sensitivity pattern of antibiotics. That report shows which antibiotics will be active against your infection. Did the report mention that ciprofloxacin, nitrofurantoin (macrobid) and norfloxacin were active against your infection? If not, we need to treat you with an antibiotic to which the organism is sensitive. 2. There may be associated conditions which prolong the infection e.g. kidney stones, any obstruction in kidneys, prostate enlargement with significant residual urine etc. Ultrasonogram of kidneys, ureter, bladder and prostate with examination of post-void residual urine can find out many of the problems. 3. Did you have any pain while the physician examined your prostate? Pain while examining prostate can suggest prostatitis (infection in prostate). Some antibiotics like macrobid are not effective against this condition. 4. Do you have diabetes? This can also cause poor response to antibiotics. I will be able to give you more guidance if you can provide me more details as per this discussion. Wish you a speedy recovery, Dr. Raguram.