UTIs and Urine Bacteria in Aging:
How to get the right diagnosis & avoid unneeded antibiotics

Q: An older friend, who is in her 90s, has been having bacteria in her urine, but no symptoms. Despite treatment with antibiotics, she was still having bacteria in the urine, so the doctor recommended chronic antibiotics and a referral to urology.

What can be done when an elderly woman has bacteria in her urine but no symptoms? Can a urology consultation help?

A: This is a great question. People often think that your friend is having a “recurring urinary tract infection (UTI)” or even a chronic UTI. But actually, you are describing something called asymptomatic bacteriuria, which means having urine bacteria without symptoms.

Every older person and family caregiver should know about asymptomatic bacteriuria. Here’s why:

• It’s very common in older adults. This condition is found in an estimated 20% of women aged 80 or older, and also affects older men. The older the person, the more common it is. Asymptomatic bacteriuria is even more common in nursing homes, where it’s estimated to affect 30-50% of residents.

• It’s often confused with a urinary tract infection (UTI).  This can lead to unnecessary — and potentially harmful — treatment with antibiotics.

• It usually does NOT need to be treated with antibiotics. As I’ll explain below, research shows that people don’t live better or longer when asymptomatic bacteriuria is treated. In fact, such treatment can be harmful: one study found that treatment increased the risk of future (real) UTIs, and increased the risk of infection with antibiotic-resistant bacteria.

• It’s common for older adults to inappropriately be given antibiotics to treat this condition. Part of why this happens is that distinguishing this condition from a real UTI cannot just be done with a urine test. Instead, health providers must take the time to talk to the patient — or family caregiver — and ask about whether symptoms are present. In a busy clinical environment, this step is all-too-often neglected.

In short, this is another one of those common aging health issues that can easily be mismanaged, unless older adults and family caregivers know to ask extra questions.

Because it’s so common for antibiotics to be inappropriately prescribed for this condition, “Don’t treat asymptomatic bacteriuria with antibiotics” is the number one “Choosing Wisely” recommendation from the Infectious Disease Society of America. The American Geriatrics Society also includes this recommendation on its Choosing Wisely list.

Now, let’s try to equip you to understand this common condition. This will help you — and your older loved ones — avoid unnecessary testing and antibiotic treatment. Specifically, in this article I’ll cover:

• What is asymptomatic bacteriuria?
• How common is asymptomatic bacteriuria?
• How to tell the difference between asymptomatic bacteriuria and a UTI
• Why asymptomatic bacteriuria usually doesn’t warrant antibiotics

I’ll close with some practical tips for older adults and family caregivers concerned about UTIs and/or bacteria in the urine.

I also did a two-part interview with colleague and expert Chrissy Kistler, MD, on this very topic.

What is asymptomatic bacteriuria?

Asymptomatic bacteriuria means having significant quantities of bacteria in the urine, but no clinical signs of inflammation or infection.

In other words, in asymptomatic bacteriuria, a urine culture will be positive. (This means that if your healthcare provider takes a sample of urine and a clinical laboratory incubates it, within 1-2 days, a sizeable quantity of bacteria will grow.)

When bacteria are present in the bladder but not provoking an inflammatory reaction, this can also be called bacterial “colonization” of the bladder.

How common is asymptomatic bacteriuria?

Asymptomatic bacteriuria is more common in older adults than many people — including practicing clinicians — may realize:

• In women aged 80 or older, 20% or more may have this condition.
• In healthy men aged 75 or older, 6-15% have been found to have bacteria with no UTI symptoms.
• Studies of nursing home residents have found that up to 50% may have asymptomatic bacteriuria.

This condition also affects 2-7% of premenopausal women, and is more common in people with diabetes.

Asymptomatic bacteriuria becomes more common as people get older, in part because it is related to changes in the immune system, which tends to become less vigorous as people age or become frailer.

Studies have found that in older adults, asymptomatic bacteriuria does sometimes go away on its own, but it also often comes back or persists.

How to tell the difference between asymptomatic bacteriuria and a UTI

By definition, in asymptomatic bacteriuria, there should be no UTI symptoms present.

The following signs and symptoms can be caused by UTI:

• Burning or pain with urination
• Increased frequency or urgency of urination
• Bloody urine
• Pain in the low abdomen, flank, or even back
• Fever

(What about “cloudy” or “foul-smelling” urine? In the absence of other symptoms, no study has shown that this is a good way to detect a possible UTI. See here: Cloudy, Foul-Smelling Urine Not a Criteria for Diagnosis of Urinary Tract Infection in Older Adults.”)

Whether or not an older person has a clinical UTI, the urine dipstick may be abnormal, in part because certain abnormal results suggestive of UTI may in fact only reflect bacterial colonization of the bladder. So one should not rely on urine dipsticks or related urine analysis tests (which measure the number of white blood cells in the urine, among other things) as the sole justification for diagnosing a UTI. Symptoms are necessary!

The thing is, some older adults may only show vague or non-specific symptoms when they get a UTI, such as confusion or weakness. (That “confusion” would be delirium.) This is especially true of aging adults who are frail, or are quite old, or have Alzheimer’s or another dementia.

For this reason, it can be difficult to determine whether a frail or cognitively impaired older person is having UTI symptoms that warrant treatment.

Experts have debated whether it’s justified to treat for possible UTI, for those cases in which an older person with asymptomatic bacteriuria shows signs of delirium, but no other UTI symptoms.

Why asymptomatic bacteriuria usually doesn’t warrant antibiotics

Clinical studies overwhelmingly find that in most people, treating asymptomatic bacteriuria with antibiotics does not improve health outcomes. Even when it comes to the nursing home population, which is frailer than the general population, a 2022 systematic review found that antibiotic treatment of asymptomatic bacteriuria didn’t improve outcomes.

(The exceptions: pregnant women and men about to undergo urological procedures do benefit from screening for and treatment of asymptomatic bacteriuria.)

A 2015 clinical research study found that treatment of asymptomatic bacteriuria in women was associated with a much higher chance of developing a UTI later on, and that these UTIs were more likely to involve antibiotic-resistant bacteria.

Even when it comes to the nursing home population, which is frailer than the general population, a 2022 systematic review found that antibiotic treatment of asymptomatic bacteriuria didn’t improve outcomes.

Despite the expert consensus that this condition doesn’t warrant antibiotics, inappropriate treatment remains very common. A 2014 review article on this topic noted overtreatment rates of up to 83% in nursing homes. To combat this issue, this 2023 BMJ article outlines an approach nursing homes can take: Reducing unnecessary urine culture testing in residents of long term care facilities.

Is there a role for cranberry to treat or manage urine bacteria?

The use of cranberry juice or extract to prevent UTIs has been promoted by certain advocates over the years, and many patients do prefer a “natural” approach when one is possible.

However, top quality clinical research has not been able to prove that cranberry is effective for this purpose. In a 2016 study of older women in nursing homes, half were given cranberry capsules daily. But this made no difference in the amount of bacteria or white blood cells in their urine.

In a related editorial titled “Cranberry for the Prevention of Urinary Tract Infection? Time to Move On,” which summarized many other studies of cranberry for the prevention of UTI, the author concluded:

The evidence is convincing that cranberry products should not be recommended as a medical intervention for the prevention of UTI. A person may, of course, choose to use cranberry juice or capsules for whatever reason she or he wishes. However, clinicians should not be promoting cranberry use by suggesting that there is proven, or even possible, benefit. Clinicians who encourage such use are doing their patients a disservice.”

A 2012 systematic review of high-quality research studies of cranberry for UTI prevention also concluded that cranberry products did not appear to be effective.

That said, many people really feel that cranberry supplements make a difference.

As cranberry is unlikely to cause harm to older adults, I don’t object when an older person or family caregiver wants to use them. But I don’t particularly encourage it either.

Practical tips on urine bacteria and possible UTIs in older adults

Given all this, what should you do if you are worried about bacteria in the urine, or a possible UTI?

Here are my tips for older adults and families:

• Realize that asymptomatic bacteriuria is common in older adults.
  • If you keep having positive urine cultures despite feeling fine, you may have asymptomatic bacteriuria.

• Know that treatment of asymptomatic bacteriuria is not going to help, and might lead to harm.
  • Unless you are having symptoms, it’s pointless to try to “eradicate” bacteria from the bladder. Studies show that this increases your risk of getting a real UTI later on, and that you’ll be more likely to be infected with bacteria that are resistant to antibiotics.
  • Antibiotic treatment also affects the “good bacteria” in your gut and elsewhere in the body. Research to help us understand the role of the body’s usual bacteria (the “microbiota”) is ongoing, but suggests there can be real downsides to disrupting the body’s bacteria. So you don’t want to use antibiotics unless there’s a good reason to do so.

• Avoid getting a urine culture unless you’re experiencing symptoms of likely UTI, such as pain with urination or low belly pain.
  • Some healthcare providers will do a urine culture “just to check” for UTI. Or sometimes patients and family members request this. But this is a bad idea, since all you might do is uncover signs of asymptomatic bacteriuria (which then has a tendency to be inappropriately treated with antibiotics).
  • Experts strongly recommend that urine tests for possible UTI only be done if an older person is experiencing symptoms.
  • If a health provider suggests a urine test and you aren’t having UTI symptoms, inquire as to the purpose of the test.

If you’re caring for an older adult who has dementia or is otherwise prone to delirium:

• Realize that it can be tricky to determine whether the person is experiencing UTI symptoms.
  • The doctors should still attempt to do so before checking a urine culture or treating any bacteria found in the urine. Specific symptoms to check for include dysuria (painful urination), fever, and lower belly pain.
• Realize that some experts believe that increased confusion alone (meaning no fever or other signs of UTI) may not be a good reason to treat a nursing home resident for a presumed UTI.
  • A geriatrician explains this debate in this very interesting article: “Urinary Tract Infection”—Requiem for a Heavyweight

In short: I’d summarize the benefits and burdens of treating asymptomatic bacteriuria in a 90-year-old woman as follows:

Benefits: No proven benefit to antibiotic treatment in someone who doesn’t have clinical signs of a UTI.

Burdens: Antibiotics cost money, and increase pill burden. There is a risk of side-effects, of interactions with other medications, of harming your body’s “good bacteria,” and of developing an infection resistant to antibiotics. Also, the overuse of antibiotics in society means we are developing more resistant bugs all around us.

So there you have it. If an older person has a positive urine culture but no symptoms, think long and hard before agreeing to treatment. And ask extra questions before spending time pursuing a urology consultation. The second part of my two part interview with Chrissy Kistler, MD, focuses on UTIs in older adults with Alzheimer’s and related dementia.

Remember, bacteria in the urine does NOT equal a UTI.

So, ask your clinicians if this could be asymptomatic bacteriuria. Tell them you’ve heard that the Infectious Disease Society of America, the American Geriatrics Society, and other experts say that this condition should not be treated in older adults. (Unless you’re about to undergo a urological procedure.)

You can even share these peer-reviewed articles:

• Reducing unnecessary urine culture testing in residents of long term care facilities
• Approach to a Positive Urine Culture in a Patient Without Urinary Symptoms
• Diagnosis and Management of Urinary Tract Infection in Older Adults
• “Urinary Tract Infection”—Requiem for a Heavyweight

This article was first published in 2015. It was reviewed and updated by Dr. Kernisan in February 2024. (The basics about asymptomatic bacteriuria and UTIs in aging adults don’t change much!)