Stone Culture Positive in Analysis of Calcium-Based Stones: A Case Report.

Calcium-based urinary stones rarely grow bacteria on stone culture. The presence of an anaerobic bacteria is even more uncommon. We present a case of growth from a primarily calcium phosphate-based urinary stone culture. A 56-year-old Caucasian woman presented with urosepsis and bilateral nephrolithiasis. A nephrostomy tube was emergently placed in the left kidney. After resolution of her urosepsis, she underwent a left percutaneous nephrolithotomy. The stone culture grew , a gram-negative anaerobe. Growth of anaerobic bacteria, such as , on stone culture of a calcium-based stone is a rare occurrence; the mechanism of this association remains unexplained.