Crystal Formation Induced by Uropathogenic Bacteria

Human urine was studied in regard to precipitation of crystals under various experimental conditions. These included alkalization of the urine by adding NaOH or by inoculation with Proteus bacteria. The contents of calcium and magnesium in the urinary supernatant after incubation for 24 hours at 37 degrees C were significantly lower after inoculation with Proteus bacteria than in noninoculated urine. Microscopy of the sediments showed distinct crystalline aggregations after the bacterial inoculation. Inoculation with killed Proteus organisms did not lead to crystalline precipitation in otherwise identical experiments. The effect of other live bacteria was also studied. The mechanism of crystal formation in bacteria-inoculated urine is discussed.