Will Doxycycline impact by STI or bacterial cultures testing

[Dneck]

I have been on Doxycycline for 14 days and I still have symptoms of an STI or NGU.  I have red swelling on the bottom of my penis and also have clear discharge and experience burning after I pee.  I was tested for chlamydia/Gonorrhea, HIV, Syphilis as well as for herpes type 1 and 2 before starting Doxycycline . which were all negative.  Recently I have taken a round azythromycin (four pills at once) with no effect.  This has been going on for well over two months.  My doctor is struggling to help me.    She now wants me to perform a bacterial culture and Urinalysis to see if there is anything else causing this issue.  

My question is should I wait to get this testing done.  I have read on forums that you possibly wait 3 weeks because of the the impact of antibiotics on testing but I can't imagine waiting this long for the testing as it is causing me anxiety and pain.

[Joejoesmith]

many different bacteria can cause NGU, they were never able to culture mine to test for sensitivity so if they can that's great, otherwise it's a shot in the dark as to what antibiotic will be effective against your particular infection

[Joejoesmith]

Having had NGU myself I can tell you it took me four different meds to eliminate it. Leviquin finally did the trick for me after thw infection made its way to my prostate(not fun). It will not skew results as if you still have an infection your urine will produce WBC