From a New York Times online article:
At Dr. Soong’s hospital, withholding the results of urine cultures, unless doctors actually called the microbiology lab to request them, reduced prescriptions for asymptomatic bacteriuria to 12 percent from 48 percent of non-catheterized patients, with no loss of safety.
“The extra step of having the clinician call eliminated a lot of frivolous testing,” Dr. Soong said.
In patients who have none of the typical symptoms of a urinary tract infection — no painful or frequent urination, no blood in the urine, no fever or lower abdominal tenderness — lab results detecting bacteria in the urine don’t indicate infection and thus shouldn’t trigger treatment.
Older people, and nursing home residents in particular, often have urinary systems colonized by bacteria; they will have a positive urine test almost every time, but they’re not sick.