
For the first time, scientists have discovered evidence of the presence of bacteria hidden inside kidney stones called "non-infectious".
These hard clumps of small crystals are formed from chemicals in the urine and are thought to be caused by a lack of fluids or a high concentration of minerals and chemicals.
Most kidney stones are considered non-infectious. But this may not be true.
A study led by researchers at the University of California, Los Angeles (UCLA) has found that calcium oxalate kidney stones, the most common type, are rich in bacteria.
In fact, these stones contain layers of bacteria as part of their internal structure.
"This discovery challenges the assumption that these stones develop solely through chemical and physical processes, and instead shows that bacteria can reside within the stones and even actively contribute to their formation," explains urologist Kymora Scotland from UCLA.
“By uncovering this novel mechanism, the study opens the door to new therapeutic strategies that target the microbial environment of kidney stones.” The findings suggest that in some cases where kidney stones repeatedly recur, there may be a bacterial infection in the kidney, ureter or bladder that contributes to the recurrence.

If this infection is treated, then perhaps there may be fewer kidney stones in the future.
Using electron and fluorescent microscopy, the researchers found structural and chemical evidence of bacteria in calcium oxalate stones taken from patients. This was true even in participants without urinary tract infections.
"We found a new mechanism of stone formation that may help explain why these stones are so common," says Scotland.
"These results may also help explain the links between recurrent urinary tract infections and recurrent kidney stone formation, as well as provide insights into potential future treatments for these conditions."
More than one in 11 people will suffer from kidney stones in their lifetime, and over 70 percent of cases are attributed to calcium oxalate stones. If bacteria play a significant role in their formation, then treatments and guidelines for kidney stones may need to be updated, writes Science Alert.