Intracellular crystal formation in bacteria from human urines: A contributing factor in urinary calculi

Marc S. Cohen, Michael M. Warren, Paul Baur, James J. Vogel, C. P. Davis

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Understanding of the bacterial contribution to urinary calculi has been limited to those organisms capable of altering the urine through urease activity. Sterilized urines from stone forming and non-stone forming individuals were inoculated with bacteria having either strong, weak, or no urease activity. All organisms grown in unbuffered urines produced crystallization (calcite or apatite) as demonstrated by X-ray diffraction. Bacteria grown in conventional medium (Heart Infusion broth) did not demonstrate crystal formation. Unstained specimens revealed electron-dense deposits within bacteria grown in urine. Deposits were not present in organisms grown in conventional media. Analysis revealed increased levels of calcium within these deposits as compared to extracellular levels. These findings support the hypothesis that both urease producing and non-urease producing organisms may accumulate calcium crystals intracellularly and form nidi for calculus formation.

Original languageEnglish (US)
Pages (from-to)55-61
Number of pages7
JournalUrological Research
Issue number2
StatePublished - Apr 1981
Externally publishedYes


  • Bacteria
  • Calculus disease
  • X-ray diffraction

ASJC Scopus subject areas

  • Urology


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