I tested positive so they say with the first two urine tests. Seems e-coli was in the first test, then I took the antibiotic and took another test, which showed pseudomonas. I went to another doctor for a urine analysis. Because my primary care doctor's office refused to give me another urine test because it came back positive. The strip test was clear (no positive for nitrates or leukocytes but the more complex culture showed "mixed flora." I got that test at another doctor's office. It was said it might not have been a clean catch. That may be so. Question is: how is it that the initial urine dipstick test was negative but the further test showed bacteria (or "mixed flora")? Thanks for anybody to help explain this. My doctors' office certainly won't.