A recently discovered class of micro-organisms termed "nanobacteria" because of their very small size may be responsible for the development of kidney stones. Researchers at the University of Kuopio in Finland found that the nanobacteria form stone shelters around themselves that closely resemble the mineral aggregates found in kidney stones. The calcium phosphate deposits found in kidney, gall and bladder stones were previously thought to be associated with altered acidity levels and abnormal calcium and phosphate concentrations in the body. Nanobacteria, the smallest known bacteria with a cell wall, could form their stone coats in the absence of such conditions, the researchers report in the Proceedings of the US National Academy of Sciences.
Cells infected with the bacteria developed mineral deposits and an analysis of 30 human kidney stone specimens revealed that all of them contained nanobacteria.