Detection and identification of oxalate-degrading bacteria in human feces.

Abstract

Oxalate is detoxified (catabolized) via the action of two enzymatic proteins, formyl coenzyme A transferase (encoded by the frc gene) and oxalyl coenzyme A decarboxylase (encoded by the oxc gene), contained in the cytosol of Oxalobacter formigenes that colonizes the human intestinal tract. It is speculated that oxalate-degrading bacteria decrease oxalate absorption from the intestines and their absence in the gastrointestinal tract correlates with the formation of calcium-oxalate urolithiasis. Two methods of detection and identification of this bacterial strain were studied in human fecal samples collected from Japanese subjects. Genomic DNA was isolated from bacterial culture, and specific 16S rDNA was amplified by polymerase chain reaction (PCR) followed by sequencing. The oxc gene was amplified directly from human feces by PCR using the specific primers. Oxalate-degrading bacteria were identified by comparing the sequences of 16S rDNA. The oxc gene was directly detected from human feces by PCR. It was ascertained that a combined PCR detection method using both 16S rDNA and the oxc gene allows for identification of O. formigenes in human fecal samples. This detection and identification method of oxalate-degrading bacteria using 16S rDNA and oxc gene should be applied in examination of clinical samples.