There has already been a pretty comprehensive evaluation - including being scoped four months ago without evidence of polyps or scarring.
The only other suggestion I would make would be to ensure the prostate is not infected. This would include a prostatic massage and culturing off any fluid that is expressed. This can evaluate whether there is any bacteria that is resistant to the antibiotics you are taking.
If negative, I would suggest a transrectal ultrasound. This can image the prostate and evaluate for any abscesses - which would take more than antibiotics to treat.
You may want to discuss these options with your personal physician.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
Medical Weblog:
kevinmd_b