Calcified bacteria in renal stones: electron-microscopic aspects.

In some renal calculi whose structure was studied in thin sections, we have found large numbers of rods of the size and shape of bacteria, included in a material consisting of defective apatite calcium phosphates and organic matter. Electron transmission microscopy showed patterns of partially calcified bacteria. With the scanning electron microscopy we obtained only images of bacterial impressions. In struvite stones bacteria are rarely found in thin sections. Extremely high ammonium alkalinisation does not seem to be compatible with the preservation of bacterial bodies capable of being calcified.