Induction of chronic bacterial prostatitis in the dog

Three methods of creating chronic bacterial prostatitis in dogs were evaluated. Injection of Escherichia coli into the prostatic or caudal vesicle artery after the prostate was pierced with a 22-gauge needle caused prostatic infection in 4 of 5 dogs. The infection persisted up to 28 days. Direct injection of E. coli into the prostate gland resulted in infection in 5 of 6 dogs which persisted up to 42 days. Injection of E. coli into the prostatic urethra after occlusion of the bladder neck caused infection in 2 of 8 dogs not subjected to piercing of the prostate gland and in 5 of 7 dogs subjected to prostate gland trauma. Infection persisted up to 28 days. Although all 3 methods resulted in persistent, chronic bacterial prostatitis, direct injection of bacteria into the prostate gland was technically the easiest to perform and resulted in the lowest incidence of concomitant infections of the rest of the urinary tract. Positive urine cultures for E. coli were found in all dogs at some time after infection. Positive urine and bladder tissue cultures were also found at necropsy in some dogs.