Direct quantification of the enteric bacterium Oxalobacter formigenes in human fecal samples by quantitative competitive-template PCR.

Homeostasis of oxalic acid appears to be regulated, in part, by the gut-associated bacterium Oxalobacter formigenes. The loss of this bacterium from the gut flora is associated with an increased susceptibility to hyperoxaluria, a condition which can lead to the formation of calcium oxalate crystalluria and kidney stones. In order to identify and quantify the presence of O. formigenes in clinical specimens, a quantitative-PCR-based assay system utilizing a competitive DNA template as an internal standard was developed. This quantitative competitive-template PCR test allows for the rapid, highly specific, and reproducible quantification of O. formigenes in fecal samples and provides a prototype for development of DNA-based quantitative assays for enteric bacteria.