Patient education: Asymptomatic bacteriuria (The Basics)

What is asymptomatic bacteriuria? — This is the medical term for when there is more bacteria than normal in a person's urine, but the person does not have symptoms of infection. It is more common in females, older people, and people with certain medical problems. It is also common in people who use a urinary catheter. (A catheter is a tube that is placed into the urethra (figure 1) if a person is not able to urinate normally.)

Asymptomatic bacteriuria usually goes away on its own, and does not lead to problems. In most cases, it does not need treatment.

How do I know if I have asymptomatic bacteriuria? — A urine test can show if there is bacteria in your urine. But most people who don't have any symptoms don't need this test. You might find out you have asymptomatic bacteriuria after a urine test if you are pregnant, are planning to have certain types of surgery, or recently had a kidney transplant.

What are urinary tract infections? — Urinary tract infections, also called "UTIs," also involve bacteria in the urine. But UTIs cause symptoms and require treatment.

UTIs affect either the bladder or the kidneys. Bladder infections are more common than kidney infections. Bladder infections happen when bacteria get into the urethra (the tube that carries urine out of the body) and travel up into the bladder. Kidney infections happen when the bacteria travel even higher, up into the kidneys. UTI symptoms can include pain or a burning feeling when you urinate, the need to urinate often or suddenly, and blood in the urine. Kidney infections can also cause fever, back pain, and nausea or vomiting.

While asymptomatic bacteriuria and UTIs both involve bacteria in the urine, the difference is that people with asymptomatic bacteriuria do not have symptoms. Also, people with UTI symptoms need treatment with antibiotics, but most people with asymptomatic bacteriuria do not (see below).

Do I need antibiotics? — Probably not. Most people with asymptomatic bacteriuria do not need any treatment. But some people do. That's because in certain cases, the bacteria could lead to an infection and cause problems.

Your doctor will probably treat you with antibiotics if you:

●Are pregnant

●Are planning to have certain types of surgery involving the urinary tract or genital area

●Have recently had a kidney transplant

If you are not in any of the above groups, and you do not have any symptoms of a UTI, you probably don't need antibiotics. That's because:

●Bacteria in the urine usually go away without treatment.

●If you don't have any symptoms, antibiotics will not change your overall health or make you feel better. They also won't lower your risk of getting a UTI in the future.

●Antibiotics can cause side effects such as nausea, vomiting, and diarrhea.

●Using antibiotics when they are not needed can lead to "antibiotic resistance." This is when bacteria change so that antibiotics cannot work on them.

Can asymptomatic bacteriuria be prevented? — No. There is no proven way to prevent asymptomatic bacteriuria. And most people who have it don't even know it, since it does not cause any symptoms and usually goes away on its own.

More on this topic

Patient education: Urinary tract infections in adults (The Basics)
Patient education: Urinary tract infections in pregnancy (The Basics)
Patient education: Using a catheter to empty the bladder (The Basics)
Patient education: What you should know about antibiotics (The Basics)

Patient education: Urinary tract infections in adolescents and adults (Beyond the Basics)