Abstract
Two oligonucleotide probes selected from the sequences of cepA and cfxA genes, respectively, were used to detect beta-lactamase production among strains of the Bacteroides fragilis group. By using these probes, colony hybridization was shown to be a specific and rapid method for identifying the more prevalent beta-lactamase, CepA, and the rarer CfxA enzyme among B. fragilis strains.