A urine culture is typically obtained when a person has urinary symptoms of infection (burning, frequency) and/or abnormal results from a urinalysis. It also often obtained prior to a surgery, most often prior to surgery involving the urinary tract. A sample of the urine is processed to see if any bacteria grow out of the urine. Then this bacteria is analyzed to see which antibiotic would best eliminate it. It is important to follow urine specimen collection instructions carefully to avoid growing bacteria from the skin (and not from the bladder or urine).
If a person has an indwelling urinary tube or catheterizes themselves it is very likely that any urine culture will grow bacteria. These bacteria typically only need to be treated if the person has signs or symptoms of urinary tract infection. An exception to this rule is prior to a surgery, where it is often best to treat positive urine cultures for at least 24-48 hours that best target the bacteria cultured. Untreated urinary tract infections can occasionally lead to cancellation of surgical procedures.