Jones R F, Young P S, Marosszeky J E
Br J Urol. 1982 Jun;54(3):316-9. doi: 10.1111/j.1464-410x.1982.tb06987.x.
It is unnecessary to treat laboratory-diagnosed urinary tract infection in the absence of clinical symptoms and signs in patients from whom specimens of urine have been taken from indwelling urethral catheters left in situ for more than one week. If there is clinical evidence of infection, the catheter should be removed, a new catheter inserted and a specimen taken for examination. Alternatively, a suprapubic aspirate of urine may be examined bacteriologically as a treatment guide. In the absence of symptoms or other signs of infection it is doubtful whether chemotherapy is indicated.