Urinary tract infections, or UTIs, are on the rise—and they may be becoming more dangerous. The overall disease burden associated with UTIs has increased by more than 68 percent between 1990 and 2019. At the same time, the bacteria that cause UTIs have developed resistance to common drugs.
Usually, UTIs are thought of as more of a painful nuisance rather than dangerous or fatal. But for an elderly patient or someone with multiple medical conditions, the antibiotics that fight the infection can be essential. Failing to get these antibiotics contributes to the deaths of hundreds of thousands of people every year globally. Even when they aren't deadly, the more than 400 million annual worldwide UTI cases significantly strain limited medical resources.
"We know UTIs are a tremendous cause of morbidity and even mortality, but they are also a huge burden on the U.S. healthcare system—contributing to well over $2 billion annually in healthcare costs," says Michelle Van Kuiken, a urologist and a urogynecologist at the University of California, San Francisco.
Working to ease this burden, scientists have been seeking to identify and understand lesser-known contributing factors. One culprit may come as a surprise: meat contaminated by Escherichia coli bacteria.
What are UTIs and how dangerous are they?
UTIs can start in any part of the urinary system and can affect the kidneys, bloodstream, and uterus, but they most commonly infect the bladder "with symptoms of urinary frequency, urgency to urinate (sometimes despite having an empty bladder), and burning during urination," says Craig Comiter, a urologist at Stanford University. Cramping, fever, malodor, and blood in the urine can also be signs of a bladder infection.
UTIs occur when bacteria enter the urethra and infect the urinary tract—something that can occur during sexual activity, because of a genetic predisposition, or due to poor hygiene practices such as not wiping properly.
UTIs are the most common infection treated outside of hospitals in the United States, affecting some 50-60 percent of women during their lifetime. Roughly a quarter of women also report repeat infections within six months.
While UTIs can happen to anyone, they are about 30 times more common in women because females have shorter urethras that are closer in proximity to the anus—a common source of bacteria. Broken down, "the groups at most risk for infections are sexually active women, elderly women, and immunosuppressed men and women," says Comiter.
When UTIs only affect the bladder, they aren't considered dangerous and usually resolve without treatment—though antibiotics are frequently prescribed to speed the healing process up from weeks to days. When these infections spread to the kidneys, bloodstream, or to different areas of the reproductive system, however, they can lead to serious complications such as blood poisoning, sepsis, kidney damage, or kidney failure.
When left untreated, "a very small percentage of these cases can even be life-threatening," explains Jacob Lazarus, an infectious disease physician at Massachusetts General Hospital and a bacterial cell biologist at Harvard Medical School.
Why are the number of UTIs increasing?
The increasing number of UTI cases are due to several factors, one of which is a burgeoning population. "As the population increases, we expect more UTIs and more [of the disease burden associated with] UTIs because there are more people," says Lazarus.
On top of that, some of the conditions associated with UTIs, such as kidney stones and type 2 diabetes, are also on the rise. And a high number of teens and adults are sexually active. "In otherwise healthy women, sexual activity is the number one contributor to developing a UTI," says Van Kuiken.
The global population is also getting older. "Because UTIs are more common in seniors, their prevalence is increasing as the population ages," says Comiter.
