A urine culture is a medical laboratory test that doctors may use to investigate the cause of a urinary tract infection. Some physicians also have a patient undergo a type of urine culture test known as sensitivity testing to help them decide on the best course of treatment for a urinary tract infection. People with urinary tract infections can have urine culture testing performed to measure the effectiveness of the treatment they have already received in some instances. In most cases, the clean catch method is used to collect a urine sample for testing, although some patients use a urinary catheter to provide a urine specimen.
Patients typically clean the area around the genitals before sample collection to prevent contamination of a urine sample. When using the clean catch method, a patient often begins by passing a small amount of urine from the urethra into the toilet bowl to flush any contaminants that may be in the urethra. After flushing the urethra, a patient typically urinates about two ounces (60 ml) of urine into a sterile container and removes the container from the urination stream without stopping urination.
The patient generally submits the urine sample to a medical professional to send to a laboratory for testing. Abnormal results from urine culture testing may indicate that a patient has excessive bacterial growth in the urine sample as well as an active bladder infection or other urinary tract infection. In some cases, patients have false negative results from a urine culture test if they have recently been taking antibiotics.
A urinary tract infection is generally a bacterial infection that develops in the bladder, kidneys or another part of the urinary tract. In most cases, urinary tract infections tend to be caused by bacteria. Women typically have a higher risk of developing a urinary tract infection because they often have a shorter urethra than men. People with diabetes, kidney stones and bowel incontinence may also be more susceptible to a urinary tract infection. Individuals who have difficulty passing urine due to factors such as blockage of the urinary tract, an enlarged prostate or pregnancy may have a higher risk of developing an infection of the urinary tract.
Common symptoms of a urinary tract infection include pain in the lower abdomen as well as urine that is cloudy, bloody or has a strong odor. Some people may develop pain during urination, a low-grade fever or an increased need to urinate with an infection of the urinary tract. Infections that spread to the kidneys may cause chills, fatigue or an increased fever. Confusion and other mental changes can occur in older people who have kidney infections. Most patients with urinary tract infections receive treatment with oral antibiotics, and some severe infections may be treated in a hospital with intravenous antibiotics.