Tuesday, December 12, 2006

UTI Question: Why is my urine culture positive, but I have no symptoms.

The urine culture is the diagnostic test of choice to accurately diagnose a UTI (urinary tract infection). Often, a female patient will be told she has a positive urine culture, even if she has no symptoms suggestive of a UTI, such as burning with urination (dysuria), frequency, urgency, or voiding in small amounts. This condition has a name and is called asymptomatic bacteriuria.

Asymptomatic bacteriuria is common in elderly patients, most commonly women, and occurs in greater than 80% of people in nursing homes. Young women also can have asymptomatic bacteriuria. Whether or not the bacteria should be treated with an antibiotic depends on a variety of factors.

In general, the first question that should be asked when a young woman has bacteria in the urine is how the specimen was collected. Urine specimen collection in woman can be somewhat problematic due to contamination of the specimen as it comes out of the urethra and traverses across the vaginal and labial tissue. For this reason, women are instructed to give a clean catch, midstream collection.

There are certian instances in which a young woman will have multiple, positive clean catch midstream urine cultures, yet have no UTI symptoms. In this case, rather than simply give multiple course of antibiotics, it is best to take a sample of urine directly from the bladder, painlessly, with a tiny catheter. If the culture by this method is negative, then the other cultures were most likely contaminated and no treatment is necessary. If, however, the catheterized sample is positive, evaluation for the source of the bacteria is indicated.

Dr S.