If its bacterial prostatitis, and you have a UTI or similar, you need an 'antibiotic susceptibility test' performed on your urine. They can test your urine against like 20 or so ab's. Some will be resistant, some not. Obviously, take an antibiotic thats susceptible. It's worth a try. If you have a bacterial infection though, you might have other symptoms like odd smelling urine, burning, stinging etc.. Go for an AB that has good prostate penetration.