I have a history of UTI's, especially while I was sexually active. They always responded well to antibiotic treatment. Now that I'm no longer active, I still get a UTI once or twice a year. The last one was treated but when I went back to the doc's office for a urine test, it showed no bacteria but traces of blood. I purchased dip sticks to keep monitoring. I still have occult blood in the urine and a slight burning sensation, but not while urinating. What could be the problem? Thank you in advance for your response.