Urinary tract infection induced by intermittent urethral catheterization in dogs.

Sterilized and unsterilized catheters were passed into the urinary bladders of 9 clinically normal adult male dogs once daily for 5 consecutive days, and the dogs were examined for up to 30 days to determine whether urinary tract infections developed. Two dogs that were catheterized with clean unsterilized catheters (1 clinically normal dog and 1 dog given immunosuppressant drugs) developed persistent cystitis and pyelonephritis due to infection with Proteus sp. One dog given immunosuppressant drugs developed a mixed bacterial infection (Proteus sp and Escherichia coli) that resolved without treatment between 22 and 30 days later.