IDENTIFICATION AND CLASSIFICATION OF OXALOBACTER-FORMIGENES STRAINS BY USING OLIGONUCLEOTIDE PROBES AND PRIMERS

Genomic DNAs of various strains of Oxalobacter formigenes were subject ed to restriction endonuclease fragment length polymorphism- and PCR-b ased amplification analyses with DNA probes and primers complementary to sequences within either the ore gene, encoding oxalyl coenzyme A (o xalyl-CoA) decarboxylase, or the frc gene, encoding formyl-CoA transfe rase, Oligonucleotide probes based on nonconserved sequences of orc or frc were able to divide O. formigenes strains into at least two group s, consistent with the current separation of O. formigenes strains int o groups I and II on the basis of 16S rRNA sequence similarities and l ipid content. In contrast, an oligonucleotide probe based on the conse rved 5' end of oxc appeared to bind all group I and the majority of gr oup II strains, PCR amplification of the oxc gene showed even greater sensitivity in detecting O. formigenes and provided support for furthe r division of the strains into subgroups, In addition, these oligonucl eotides failed to hybridize to or amplify PCR products from whole feca l DNA isolated from fresh stool samples from an individual not coloniz ed with O. formigenes, indicating unique specificity. Thus, these DNA analyses permit both detection as well as classification of O. formige nes strains.