Urine Tests Don't Always Confirm Urinary Infections, Study Finds
Doctors can rely on symptoms to start treatment, experts say
However, the 226 women included in the current study volunteered to collect a midstream urine sample, and immediately after allowed another sample to be collected directly from their bladder via a catheter.
All of the women were healthy, premenopausal women who had symptoms of a bladder infection.
When the researchers found E. coli in the midstream urine sample, it was also quite likely that they would find it in the bladder urine, too. However, when other types of bacteria were found in the midstream urine sample, they often didn't correlate to bacteria in the bladder.
The researchers also found that when other bacteria were in the midstream urine sample, E. coli was often present in the bladder urine samples.
"E. coli is probably causing most infections," said Hooton.
"Our findings are further confirmation that collection of urine has limited usefulness. You don't get the results back for two days, and just practically speaking, it's an added cost because we know E. coli causes most UTIs," noted Hooton.
If your physician decides to treat you without asking for a urine sample to culture, that's reasonable, said the author of an accompanying journal editorial, Dr. Michael Donnenberg, a professor of medicine, microbiology and immunology at the University of Maryland School of Medicine in Baltimore.
But Donnenberg noted that this study raises a number of questions, too: "Do bacteria in the urethra cause symptoms? And, if they do, does treating them make the symptoms go away more quickly?"
The test relied on today needs to be refined if it continues to be used in clinical practice, he suggested. Millions of these tests are still performed annually, he wrote in the editorial.
Both experts said more research on when antibiotics are helpful and when they're not might help reduce potentially unnecessary antibiotic use. Reducing unnecessary antibiotic use is important because of concerns about growing antibiotic resistance.