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A groundbreaking study from Cleveland Clinic researchers provides definitive evidence of a kidney microbiome, upending the long-held belief that the urinary tract is sterile. Published in Nature Communications, the research not only demonstrates the existence of bacteria in healthy kidneys but also shows how this microbiome can influence kidney stone formation. These findings could revolutionize the prevention and treatment of kidney stones, a condition that affects millions of people worldwide.
What’s New? Linking Bacteria to Kidney Stone Formation
By employing a rigorous, multi-pronged approach—including preclinical, human, and in-vitro studies—the team, led by Aaron Miller, PhD, and José Agudelo, MD, identified stable and metabolically active bacterial communities in the kidney, meeting the criteria of a true microbiome. The researchers highlighted two key bacterial species with opposing effects on kidney stone formation: Escherichia coli (E. coli) and Lactobacillus crispatus.
The team’s experiments demonstrated that E. coli promoted the development of large calcium oxalate crystals indistinguishable from human kidney stones. In contrast, Lactobacillus crispatus inhibited this process. When the two bacteria were grown together in a laboratory chamber designed to mimic kidney conditions, only small crystals formed, which were structurally and chemically different from typical kidney stones.
The research also found that antibiotic overuse disrupted the balance of the kidney microbiome, shifting it toward a predominance of stone-forming bacteria like E. coli. This may help explain why individuals on long-term antibiotic therapy are at greater risk of developing kidney stones.
Why It Matters: Shaping the Future of Kidney Stone Prevention
“Urologic diseases like kidney stones impact 63% of the adult population and are getting worse,” Dr. Miller said in the study. “The data consistently points towards bacteria. If we can’t get over the assumption of sterility, we can’t develop more effective treatments and preventative options.”
Kidney stone prevalence is increasing, yet treatment options have remained stagnant for decades. Understanding the role of the kidney microbiome opens new possibilities for developing targeted therapies and preventive strategies. Dr. Miller and his team’s findings suggest that restoring or maintaining healthy bacterial populations—such as Lactobacillus crispatus—could prevent kidney stones and improve renal health.
“Antibiotics are one of – if not the – most miraculous inventions of the modern age, but they do not come without consequences,” Dr. Miller noted. He emphasized the need to balance antibiotic use to avoid unintended disruptions to the kidney microbiome.
Beyond Kidney Stones: Broader Implications for Renal Health
The findings could also have implications beyond kidney stones. “If the kidney microbiome can influence kidney stones, it can likely influence other kidney diseases as well,” Dr. Miller said. His team is already investigating microbial signatures in other kidney diseases and examining how genetic variations might affect the microbiome’s role in kidney disease across different ethnic populations.
For healthcare professionals, this study highlights the importance of the kidney microbiome in understanding, preventing, and managing urologic diseases. By shifting the paradigm away from the outdated notion of a sterile urinary tract, researchers hope to pioneer new diagnostic tools and treatments that leverage the protective potential of beneficial bacteria.