An estimated 50% of all women will experience a urinary tract infection at some point in their lives, and 20-40% of these women will have recurring infections, putting them at risk for kidney and bloodstream infections. But now, new research suggests over-the-counter painkillers could help prevent such infections from occurring.
Investigators from Washington University School of Medicine in St. Louis, MO, presented their findings at the annual meeting of the American Society for Microbiology.
They found that, by inhibiting an immune protein that causes inflammation - called COX-2 - they were able to eliminate repeat urinary tract infections in mice. The team explains that COX-2 can be blocked by non-steroidal anti-inflammatory drugs (NSAIDs), which includes ibuprofen.
According to the Centers for Disease Control and Prevention (CDC), urinary tract infections (UTIs) are responsible for around 4 million ambulatory-care visits every year in the US.
Most UTIs are caused by the bacterium Escherichia coli, which lives in the bowel. While men also get UTIs, women are especially prone to them because their urethra is shorter - which allows bacteria better access to the bladder - and a woman's urethral opening is in proximity to bacteria sources from the anus and vagina.
NSAIDs, such as ibuprofen, blocked a protein that causes inflammation and significantly reduced vulnerability to repeat UTIs.
Each time a woman has a UTI, her chances of having recurrent infections increases, and severe infections with sepsis can even be fatal.
In previous mouse studies, the researchers - led by Thomas Hannan - found that the immune system overreacted to initial infections, which suggested increased vulnerability to infections that followed.
"We thought that the immune response was too weak in patients who kept getting urinary tract infections," explains Hannan, "but we are learning that an overly strong immune response can be just as problematic."
He and his team found that immune cells, called neutrophils, contribute to repeat infections in both women and mice. The neutrophils leave tracks in the protective lining of the bladder when they break in to fight infection, the researchers say.
Such damage could provide "footholds" that allow bacteria to grab hold of the bladder lining and initiate severe infections.
COX-2 inhibitors reduced susceptibility to repeat infections
By manipulating the strength of the neutrophil response in mice, so it was not too little or too much, the researchers were able to wipe out UTIs without increasing the risk of future infection.
- A frequent and intense urge to urinate and a painful burning during urination
- Cloudy, dark or bloody urine, which may have a foul smell
- Pain in the back or side below the ribs, nausea or vomiting.
They found that mice with increased susceptibility to recurring infections had more inflammatory molecules in their bladder, compared with mice that were not vulnerable to repeat infections.
However, when such mice were treated with COX-2 inhibitors, the team observed they showed a significantly reduced vulnerability to repeat infections.
After examining the effect of COX-2 inhibitors on the immune response in the bladder, the researchers found that while neutrophils still entered the bladder in large numbers, they caused significantly less damage to the protective lining.
As such, the team believes COX-2 inhibitors can selectively aim for the adverse effects of inflammation while keeping the beneficial responses.
Senior author Scott Hultgren, director of the Center for Women's Infectious Disease Research at Washington University, says their results are "encouraging," and that they "hope to verify the potential benefits of COX-2 inhibitors soon in a large clinical trial."
Hannan further comments:
"If we can confirm this link in clinical trials, many people potentially could benefit very quickly. But for now, it's important to remember that urinary tract infections are serious, and antibiotic treatment is often necessary. Patients should not treat these infections on their own without help from a medical provider."
In 2013, Medical News Today reported on a study that suggested cranberry powder can inhibit the bacterium Proteus mirabilis, a bug commonly found in complicated UTIs.