Naturally Occurring Bacteria Cut Kidney Stone Recurrence

Mar. 24 --

WEDNESDAY, March 5 (HealthDay News) -- A naturally occurring type of bacteria called Oxalobacter formigenes reduces the risk of recurrent kidney stones by about 70 percent, a new study says.

The study looked at 247 adults with recurrent calcium oxalate (CaOx) kidney stones and compared them to a control group of 259 adults. The researchers collected health and dietary information from all the participants and analyzed stool sample cultures to look for the presence of O. formigenes.

It was detected in 17 percent of people with recurrent kidney stones and in 38 percent of those in the control group.

"We observed a strong inverse association between colonization with O. formigenes and recurrent CaOx kidney stones, with a 70 percent reduction in overall risk," lead researcher David Kaufman, a professor of epidemiology at Boston University School of Public Health, said in a prepared statement.

"Our findings are of potential clinical importance. The possibility of using the bacterium as a probiotic is currently in the early stages of investigation," he said.

The study was published in the March issue of the Journal of the American Society of Nephrology.

In the United States, a person's lifetime risk of developing kidney stones is 5 percent to 15 percent, and the five-year risk of recurrence is 30 percent to 50 percent. Kidney stone-related hospital admissions cost $2 billion a year, according to background information in the study.

Up to 80 percent of kidney stones are predominately composed of CaOx, and urinary oxalate is a major risk factor for CaOx kidney stone formation, the researchers said. O. formigenes, which is present in a large number of adults, metabolizes oxalate in the intestinal tract.

More information

The National Kidney Foundation has more about kidney stones.

SOURCE: Boston University, news release, March 5, 2008