Bacteria in Kidney Stones Explain High Recurrence Rates for Patients

For decades, medical science has treated the most common kidney stones as simple mineral deposits, essentially "sterile" aggregates of chemicals formed by a lack of hydration. However, a groundbreaking study led by researchers at UCLA has shattered this conventional wisdom, revealing that these stones are actually interwoven with living bacterial colonies that may actively drive their growth.

Urologist Kymora Scotland and her team discovered that calcium oxalate stones—which account for roughly 80 percent of all cases—are not just mineral blocks but are filled with organized communities of bacteria known as biofilms. Using advanced imaging, the researchers found that these microbes are not just on the surface but are entombed deep within the stone's internal architecture, forming regular layers between mineral deposits.

The discovery explains a long-standing mystery: why kidney stones have such a high recurrence rate, reaching up to 80 percent in some patients. If viable bacteria remain hidden inside even small stone fragments after surgery, they can act as a "seed" for new stones to grow. Remarkably, the team successfully cultured living microbes from 17 out of 22 analyzed stones, including samples from patients who showed no symptoms of a urinary tract infection.

The study identifies a fascinating biological survival mechanism as the culprit. Because urine is high in calcium, bacteria release extracellular DNA to manage the calcium levels around them. This DNA is highly negatively charged, causing calcium ions to condense around it. These "calcium-dressed" DNA molecules then become nucleation sites, acting as templates where crystals begin to form and eventually encase the bacteria.

This shift from a chemical to a biological model of stone formation could revolutionize how the condition is treated for the 1 in 11 people it afflicts. Instead of relying solely on hydration and dietary changes, future therapies may target the microbial ecosystems inside the stones or use medications to disrupt the biofilms that allow them to grow. "This breakthrough challenges the long-held assumption that these stones develop solely through chemical and physical processes," Scotland noted, opening the door to new prevention strategies that could finally break the cycle of recurrent stones.

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🔖 Sources

Surprising Find Inside Kidney Stones Suggests We Were Wrong About How They Form

Most Kidney Stones May Actually Be Bacterial Colonies

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Keywords: Bacteria in Kidney Stones

Bacteria in Kidney Stones

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