prostatitis, inflammation of the prostate gland. Acute prostatitis is usually a result of infection in the urinary tract or infection carried by the blood; in many cases the infection spreads from the urethra and is contracted through sexual transmission. Symptoms include fever, low back pain, and difficulty or pain in urination; the gland is tender and swollen. Infection, caused by a variety of pathogenic bacteria and certain protozoans, is treated by an appropriate antibiotic. Healing is usually complete, but the condition may become chronic if the infecting organism persists.