Cleveland Clinic scientists have uncovered compelling evidence that challenges a long-held medical assumption: our urinary tract is not sterile after all.
Their research reveals that healthy kidneys harbor specific bacterial communities that can either promote or prevent the formation of kidney stones, opening new possibilities for treating a condition that affects millions.
_Published in [Nature Communications](https://www.nature.com/ncomms/) | Estimated reading time: 4 minutes_
In a multi-faceted study combining human, laboratory, and preclinical research, scientists have definitively proven the existence of a kidney microbiome – a discovery that could revolutionize how we prevent and treat kidney stones. The research team, led by Aaron Miller, PhD, and José Agudelo, MD, identified specific bacterial species that influence whether kidney stones form, with some bacteria promoting stone formation while others appear to prevent it.
“Urologic diseases like kidney stones impact 63% of the adult population and are getting worse,” explains Dr. Miller. “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.”
The study’s findings are particularly significant given that kidney stone treatment hasn’t seen major medical advances in over three decades. Using sophisticated laboratory techniques, the researchers demonstrated that certain bacteria, particularly E. coli, can promote kidney stone formation, while other bacteria like Lactobacillus crispatus appear to prevent it.
The research team employed an innovative approach, using a specialized chamber that mimics kidney function to study how different bacteria interact with stone-forming materials. When they introduced E. coli into this environment along with oxalate and calcium – common components of kidney stones – they observed the formation of crystal structures chemically identical to human kidney stones. However, when Lactobacillus was present, either alone or together with E. coli, it appeared to inhibit stone formation.
Perhaps most concerning, the study revealed that antibiotic overuse can disrupt this delicate bacterial balance, potentially explaining why patients on long-term antibiotic treatments often develop kidney stones. This finding suggests that careful consideration of antibiotic use might be crucial in preventing kidney stone formation.
Glossary
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* **Microbiome:** A community of microorganisms living together in a specific environment, meeting criteria of stability, consistency, reproducibility, and metabolic activity
* **Urobiome:** The specific microbiome of different organs in the urinary tract, including the bladder and kidneys
* **Metabolic Activity:** The chemical processes that occur within living organisms, including bacteria, to maintain life and function
What percentage of the adult population is affected by urologic diseases like kidney stones?
63% of the adult population is impacted by urologic diseases.
Which bacteria was found to promote kidney stone formation in the study?
E. coli was found to promote the formation of kidney stone-like crystal structures.
What are the three criteria that bacterial communities must meet to be considered a true microbiome?
Bacterial communities need to demonstrate stability, consistency and reproducibility, and metabolic activity to be considered a true microbiome.
How did the combination of E. coli and Lactobacillus affect crystal formation compared to E. coli alone?
When both bacteria were present together, only very small crystal structures formed that were structurally and chemically different from kidney stones, indicating Lactobacillus blocks E. coli’s ability to form kidney stones.
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