Got a negative urine culture test and been told: “You don’t have a UTI” when every fiber of your bladder screams otherwise? Then, you are probably one of many who understands the frustration of false UTI test results. UTI testing has remained unchanged for about 50 years and unfortunately, the wrongly negative test results reflect this.
The guidelines most doctors follow to diagnose UTIs are based on errors that have been handed down as gospel for decades. These fundamental errors produce negative UTI tests that are inaccurate, leading to delayed results, inappropriate prescription of antibiotics and frustrations for everyone. We’ve learned a lot over the past 50 years and it’s time our understanding of UTI urine tests keeps up with the times.
The bladder is not sterile
The central dogma in urine infection education is that the bladder is sterile. Medical students learn this as a fact and it influences their thinking about urinary tract infections as they become doctors and treat patients.
However, we now know this is not true- rather than being exclusively a sign of infection, most humans actually have bacteria living in their bladder. Inklings of this have been around for decades, and one researcher, Dr. Rosaline Maskell even proposed this back in the 1970s. But she, and others were ignored by the majority of scientists who doggedly held on to the status quo.
However, more recently, with advanced scientific techniques, the fact that bacteria can live peacefully within the bladder has been irrefutably proven.
The fact that bacteria live in our bladder is not a cause for alarm, as anyone who takes probiotics to replenish the “good” bacteria within their body will tell you. Just like the good guys in our gut and vagina can protect us from bowel and vaginal infections, science is beginning to show that good bacteria in our bladder may help keep us healthy and may be an important defense against getting a UTI.
In fact, some work shows that the bladder bacteria found in healthy women are similar to the protective ones found in the vagina. While more research is needed to confirm this, it is likely that these good guys can reduce inflammation, provide protective barriers and compete for space in your bladder with UTI causing bugs.
For example, women with Lactobacilli (one of the good bacteria) in their urine, are more likely to respond to treatment for overactive bladder and less likely to have a UTI caused by a catheter.
Most of all, it’s important that we don’t overtreat.
If we assume the bladder is sterile, we ignore that antibiotics can kill good bacteria along with the UTI causing bugs. Unfortunately, the good bacteria may not repopulate once we stop taking antibiotics, leaving us more susceptible to future UTIs.
In fact, this is a theory of why some women get recurrent UTIs- their overexposure to antibiotics has killed their good urine microbiome, leaving the bladder overwhelmed with bad superbugs. Therefore, they keep getting UTIs which are often very difficult to treat, over and over again.
Negative UTI test? Wrong!
A gold standard test in medicine is believed to be the “right” and the best way to diagnose a disease and is often viewed as though it is perfect. Unfortunately, urine culture tests, where scientists try to grow bacteria from a small amount of your urine in an artificial environment are not perfect. Here is why:
- We can choose the wrong environment or too short a time to grow the bacteria. The research found that 90% of urine samples that are labeled “no growth” actually can have bacteria grown from them if done right. One technique, called “enhanced quantitative urine culture” is more effective than the standard urine culture because it uses more urine, provides an environment that is better at growing bacteria and gives bacteria the time they need to grow. By using this technique, doctors can better prescribe treatments because they know what is actually in your urine.
- We ignore bacteria that we think don’t matter. Laboratories often ignore bacteria like Actinomyces (a common bacteria in the mouth) that we don’t think of as traditional UTI causing bugs. While most UTIs are caused by E.coli, there are still lots of other bacteria that can invade and infect the bladder. Of course, it is important that scientist proceed with caution and not over treat innocent bacteria. Cultures can be thorough and effective when scientist discover not only which bacteria are in the bladder but what circumstances allow them to cause harm.
- We ignore the low number of pathological bugs. A huge fallacy in UTI testing is that you need to have 100,000 colony forming units (CFU) of bacteria to have a true UTI. This number was set back in 1956, when Dr. Kass, an infectious disease doctor, was trying to make guidelines to diagnose pyelonephritis, a severe UTI that affects the kidney. This number was never meant to diagnose common urine infection restricted to the bladder, in fact, Dr. Kass was trying to exclude these more common and less serious infections! Despite this, most doctors today count 1×105 CFU as the necessary number to diagnose a UTI. Unfortunately, only half of women with UTI symptoms have that many bacteria, suggesting that the set point of 100,000 CFU misses a lot of UTIs.
Read the second part: Better UTI Testing