Kidney Stones: Bacteria Found to Play Role in Formation & Recurrence

Kidney stones are among the most dreaded pains many people fear. For years, they’ve been described as simple clusters of mineral salts that crystallize in the kidneys when you don’t drink enough fluids or consume a diet high in animal proteins. When these small “stones” migrate into the urinary tract, they can cause an extremely painful kidney stone crisis – some women who have experienced both describe it as equally painful as childbirth.

A Hidden World Within Kidney Stones

Until recently, it was believed that kidney stones had no bacterial origin. However, a research team from the University of California, Los Angeles (UCLA) has discovered hidden layers of bacteria at the core of some so-called “non-infectious” stones, prompting a re-evaluation of their origins.

Previously, bacterial infections were associated with only a minority of stones – struvite stones, representing around 10% of cases. Conversely, calcium oxalate stones (accounting for 90% of kidney stone cases) were classified as “non-infectious,” largely attributed to a chemical imbalance in the urine.

“We show here that calcium oxalate stones contain bacterial biofilms integrated into their internal structure,” explain the Harvard researchers. These biofilms may act as a framework around which crystals deposit, similar to metal bars in reinforced concrete. The study suggests that, in some patients with recurring stones, a discreet infection of the kidney, ureter, or bladder could maintain this invisible structure. “These observations could explain the recurrence of kidney stones in some patients, as well as infections due to fragmentation of the stones.”

Did You Know? Calcium oxalate stones represent 90% of all kidney stone cases.

New Avenues for Treatment

Using electron microscopy and fluorescence, researchers observed bacterial leaflets integrated into the crystalline layers, forming part of the stone’s internal structure. “This advance challenges the long-held notion that these stones develop solely through chemical and physical processes and instead shows that bacteria can live inside stones and actively contribute to their formation,” explains urologist Kymora Scotland, who participated in the study. She adds, “By revealing this new mechanism, it opens the way for new therapeutic strategies that target the microbial environment of kidney stones.”

Researchers found these bacterial signatures even in patients without a diagnosed urinary tract infection. “We found a new mechanism of stone formation that may help explain why these stones are so common,” adds Kymora Scotland. “These results may also help explain the links between recurrent urinary tract infections and repeated kidney stone formation.”

Expert Insight: The discovery of bacterial biofilms within kidney stones represents a significant shift in understanding stone formation, potentially leading to new preventative and treatment strategies focused on the microbial environment.

Frequently Asked Questions

What are kidney stones?

Kidney stones are described as clusters of mineral salts that crystallize in the kidneys.

What percentage of kidney stones are struvite stones?

Struvite stones represent approximately 10% of kidney stone cases.

What did researchers discover about calcium oxalate stones?

Researchers discovered that calcium oxalate stones contain bacterial biofilms integrated into their internal structure.

Could a better understanding of the role of bacteria in kidney stone formation lead to new ways to prevent these painful conditions?