Excellent that your urologist used EPS - most don't know to do this, and the bacteria often don't show in urine or semen samples. When your urologist redid the tests, were they also based on EPS?
Many antibiotics also have anti-inflammatory properties. People can take these, feel better, and then have the symptoms come back. What often happened in this case is that symptoms resolved as a result of the anti-inflammatory properties, which wear off when you stop taking the antibiotics, but the antibiotics never killed the infection. That can be because of wrong antibiotic, resistant bacteria, or (common in the prostate) the antibiotic never got to the infection.
A PCR test won't (as far as I know) identify if the bacteria are sensitive or resistant to the antibiotics. I think what's more usual is to culture the EPS (grow bacteria from it), and then test those against a standard set of antibiotics to find the antibiotics the bacteria is sensitive to.
Another problem is getting the antibiotics to the infection in the prostate. Prostatitis usually resides significantly in the ducts, and antibiotics often don't make it there. Only some antibiotics can get in to the prostate to work (and I don't know if the ones you list can). This may mean having prostate massage (similar as for EPS) while you're on the antibiotics.
I think you may have already seen that we have a urologist specialising in prostatitis at The FOPS. The next support meeting is probably going to be on 2nd Dec, which I would encourage you to join.