Formation of crystalline deposits by several genera of the family Enterobacteriaceae.

Several species of bacteria from the family Enterobacteriaceae formed crystalline materials containing calcium when grown in a defined culture medium. Enterobacter aerogenes, Proteus vulgaris, Citrobacter freundii, and C. intermedius produced calcium pyrophosphate crystals. Edwardsiella tarda and Escherichia coli formed calcite III crystals, whereas Proteus mirabilis, Klebsiella pneumoniae, Providencia stuartii, and Serratia marcescens produced hydroxyapatite crystals. Several of these bacteria have been isolated from the kidneys of patients with kidney stones, indicating that microorganisms may be involved in the enucleation process of kidney stone formation.