Here's my experience, got NGU from a stripper blow job. Got the shot in the butt and a one gram hit of azithro. Had a clear drip instantly cured by the shot. UTI symptoms persisted frequent urination, burn etc. went back got put on doxy for 10 days. Symptoms persisted and when I went back had pain in the anus after using bathroom and back ache, ngu moved to prostate, diagnosed with prostatis. Lexofloxin 7 days 750 MG cleared me up. Different antibiotics work on different bacteria and since ngu can be the cause of many different it can take a few try's. After all my antibiotic usage to clear this i wound up with a nasty case of balantis. Sounds like you might have something similar going on. My std tests always came back negative only had WBC and when I had prostatis had RBC in my urine. Could never culture it either