how the prostate becomes infected is not clear. the bacteria that cause prostatitis may get into the prostate from the urethra by backward flow of infected urine or stool from the rectum. at one time prostatitis was believed to be a sexually transmitted disease but more recent research suggests that only a small number of cases are passed on through sex. certain conditions and medical procedures increase the risk of developing prostatitis. you are at higher risk for getting prostatitis if you: recently have had a medical instrument such as a urinary catheter (a soft lubricated tube used to drain urine from the bladder) inserted during a medical procedure engage in rectal intercourse have an abnormal urinary tract have had a recent bladder infection have an enlarged prostate. other causes may include autoimmune disease (an abnormal reaction of the body to the prostate tissue).
what causes prostatitis?