Molecular epidemiology of fecal Oxalobacter formigenes in healthy adults living in Seoul,Korea

BACKGROUND AND PURPOSE: Oxalobacter formigenes is a member of the intestinal flora that degrades oxalate. This bacterium maintains an important symbiotic relation with its hosts by regulating oxalic acid absorption in the intestine as well as oxalic acid concentrations in plasma. We tried to define the prevalence of fecal O. formigenes positivity in healthy adults. MATERIALS AND METHODS: Whole-bacterial DNA was isolated directly from fresh stool samples obtained from 233 healthy adults known to be free of urolithiasis. Genus-specific oligonucleotide sequences corresponding to homologous regions residing in the oxc gene that encodes oxalyl-coenzyme A decarboxylase were designed. A PCR-based assay was done on the stool samples. RESULTS: A PCR product of 416 bp encoding the oxc gene was detected in 197 of the 233 stool samples (76.8%). Adjusted to the Seoul population census 1995, the calibrated fecal O. formigenes-positive rate was estimated to be 76.7%: 79.2% in men and 74.2% in women, with no significance difference according to age or sex. CONCLUSION: These results suggest that O. formigenes inhabits the intestine of three fourths of the normal Korean populations. These data provide a base for further studies to uncover the relation between O. formigenes and urolithiasis.